Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on Ce...Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on CeO_(2)and Tb-doped CeO_(2)were prepared by a precipitation method.The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,H_(2)temperature programmed reduction,and X-ray photoelectron spectroscopy.The results show that Tb-doped CeO_(2)supported Pt possesses abundant surface oxygen vacancies,good inhibition of ceria sintering,and strong metal-support interaction compared with CeO_(2)supported Pt.The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels(n-dodecane)was tested.Compared with 2Pt/CeO_(2),2Pt/Ce_(0.9)Tb_(0.1)O_(2),and 2Pt/Ce_(0.5)Tb_(0.5)O_(2),the 2Pt/Ce_(0.7)Tb_(0.3)O_(2)has higher activity and stability for hydrogen production,on which the conversion of n-dodecane was maintained at about 53.2%after 600 min reaction under 700℃at liquid space velocity of 9 ml·g^(-1)·h^(-1).2Pt/CeO_(2)rapidly deactivated,the conversion of n-dodecane was reduced to only 41.6%after 600 min.展开更多
Fe-N-C catalysts are widely considered as promising non-precious-metal candidates for electrocatalytic oxygen reduction reaction(ORR),Yet despite their high catalytic activity through rational modulation,challenges re...Fe-N-C catalysts are widely considered as promising non-precious-metal candidates for electrocatalytic oxygen reduction reaction(ORR),Yet despite their high catalytic activity through rational modulation,challenges remain in their low site density and unsatisfactory mass transfer structure.Herein,we present a structural engineering approach employing a soft-template coating strategy to fabricate a hollow and hierarchically porous N-doped carbon framework anchored with atomically dispersed Fe sites(FeNCh) as an efficient ORR catalyst.The combination of hierarchical porosity and high exterior surface area is proven crucial for exposing more active sites,which gives rise to a remarkable ORR performance with a half-wave potential of 0.902 V in 0.1 m KOH and 0.814 V in 0.1 m HClO_(4),significantly outperforming its counterpart with solid structure and dominance of micropores(FeNC-s).The mass transfer property is revealed by in-situ electrochemical impedance spectroscopy(EIS) measurement.The distribution of relaxation time(DRT) analysis is further introduced to deconvolve the kinetic and mass transport processes,which demonstrates an alleviated mass transport resistance for FeNC-h,validating the effectiveness of structural engineering.This work not only provides an effective structural engineering approach but also contributes to the comprehensive mass transfer evaluation on advanced electrocatalyst for energy conversion applications.展开更多
Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further t...Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further to synthesize heterogeneous catalyst with highly dispersed RuNi nanoparticles (Ru1Ni1.5@UiO-66(Ce)-12 h). The construction of Ce-O-Ru/Ni heterogeneous interfaces and Ni–Ru bonds provide electron transfer channels from Ce-oxo clusters and Ni species to Ru species. Furthermore, the microenvironment and electronic structure of Ru0 active sites were synergistically regulated by adjusting the content of metal-organic frameworks (MOFs) defects and Ni promoter, thereby enhancing the adsorption and activation ability of H–H and C=C bonds. Therefore, Ru1Ni1.5@UiO-66(Ce)-12 h achieved dicyclopentadiene saturated hydrogenation (100% conversion) to tetrahydrodicyclopentadiene (∼ 100% selectivity) under mild condition (35℃, 1 MPa) with only 25 min. Meanwhile, the sample exhibited excellent structural stability after 6 cycles test. This study provides a promising strategy for the rational design of remarkable noble metal-based catalysts for practical applications.展开更多
The electrocatalytic water splitting technology can generate highpurity hydrogen without emitting carbon dioxide,which is in favor of relieving environmental pollution and energy crisis and achieving carbon neutrality...The electrocatalytic water splitting technology can generate highpurity hydrogen without emitting carbon dioxide,which is in favor of relieving environmental pollution and energy crisis and achieving carbon neutrality.Electrocatalysts can effectively reduce the reaction energy barrier and increase the reaction efficiency.Facet engineering is considered as a promising strategy in controlling the ratio of desired crystal planes on the surface.Owing to the anisotropy,crystal planes with different orientations usually feature facet-dependent physical and chemical properties,leading to differences in the adsorption energies of oxygen or hydrogen intermediates,and thus exhibit varied electrocatalytic activity toward hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In this review,a brief introduction of the basic concepts,fundamental understanding of the reaction mechanisms as well as key evaluating parameters for both HER and OER are provided.The formation mechanisms of the crystal facets are comprehensively overviewed aiming to give scientific theory guides to realize dominant crystal planes.Subsequently,three strategies of selective capping agent,selective etching agent,and coordination modulation to tune crystal planes are comprehensively summarized.Then,we present an overview of significant contributions of facet-engineered catalysts toward HER,OER,and overall water splitting.In particular,we highlight that density functional theory calculations play an indispensable role in unveiling the structure–activity correlation between the crystal plane and catalytic activity.Finally,the remaining challenges in facet-engineered catalysts for HER and OER are provided and future prospects for designing advanced facet-engineered electrocatalysts are discussed.展开更多
MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V...MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling stability.Impressively,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 min.Moreover,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption properties.Notably,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.展开更多
Nickel-based materials,including metallic Ni and Ni oxide,have been widely studied in the exploration of non-precious-metal hydrogen electrocatalysts,but neither pure Ni nor NiO is ideal for the hydrogen evolution rea...Nickel-based materials,including metallic Ni and Ni oxide,have been widely studied in the exploration of non-precious-metal hydrogen electrocatalysts,but neither pure Ni nor NiO is ideal for the hydrogen evolution reaction(HER)and hydrogen oxidation reaction(HOR).In this paper,an oxygen insertion strategy was applied on nickel to regulate its hydrogen electrocatalytic performance,and the oxygen-inserted nickel catalyst was successfully obtained with the assistance of tungsten dioxide support(denoted as O-Ni/WO_(2)).The partial insertion of oxygen in Ni maintains the face-centered cubic arrangement of Ni atoms,simultaneously expanding the lattice and increasing the lattice spacing.Consequently,the adsorption strength of^(*)H and^(*)OH on Ni is optimized,thus resulting in superior electrocatalytic performance of0-Ni/WO_(2)in alkaline HER/HOR.The Tafel slope of O-Ni/WO_(2)@NF for HER is 56 mV dec^(-1),and the kinetic current density of O-Ni/WO_(2)for HOR reaches 4.85 mA cm^(-2),which is ahead of most currently reported catalysts.Our proposed strategy of inserting an appropriate amount of anions into the metal lattice could provide more possibilities for the design of high-performance catalysts.展开更多
Oxygenated carbon materials exhibit outstanding electrocatalytic performance in the production of hydrogen peroxide(H2O2)through a two-electron oxygen reduction reaction.The nature of the active functional group and u...Oxygenated carbon materials exhibit outstanding electrocatalytic performance in the production of hydrogen peroxide(H2O2)through a two-electron oxygen reduction reaction.The nature of the active functional group and underlying reaction mechanism,however,remain unclear.Here,a comprehensive workflow was established to identify the active sites from the numerous possible structures.The common hydroxyl group at the notched edge demonstrates a key role in the two-electron process.The local chemical environment weakens the binding of OOH intermediate to substrate while enhancing interaction with solution,thereby promoting the H_(2)O_(2)production.With increasing pH,the intramolecular hydrogen bond between OOH intermediate and hydroxyl decreases,facilitating OOH desorption.Furthermore,the rise in selectivity with increasing potential stems from the suppression of the four-electron process.The active site was further validated through experiments.Guided by theoretical understanding,optimal performance was achieved with high selectivity(>95%)and current density(2.06 mA/cm^(2))in experiment.展开更多
Microparticles have demonstrated value for regenerative medicine.Attempts in this field tend to focus on the development of intelligent multifunctional microparticles for tissue regeneration.Here,inspired by erythrocy...Microparticles have demonstrated value for regenerative medicine.Attempts in this field tend to focus on the development of intelligent multifunctional microparticles for tissue regeneration.Here,inspired by erythrocytes-associated self-repairing process in damaged tissue,we present novel biomimetic erythrocyte-like microparticles(ELMPs).These ELMPs,which are composed of extracellular matrix-like hybrid hydrogels and the functional additives of black phosphorus,hemoglobin,and growth factors(GFs),are generated by using a microfluidic electrospray.As the resultant ELMPs have the capacity for oxygen delivery and near-infrared-responsive release of both GFs and oxygen,they would have excellent biocompatibility and multifunctional performance when serving as microscaffolds for cell adhesion,stimulating angiogenesis,and adjusting the release profile of cargoes.Based on these features,we demonstrate that the ELMPs can stably overlap to fill a wound and realize controllable cargo release to achieve the desired curative effect of tissue regeneration.Thus,we consider our biomimetic ELMPs with discoid morphology and cargo-delivery capacity to be ideal for tissue engineering.展开更多
Recently,two-dimensional transition metal dichalcogenides(TMDs)demonstrated their great potential as cost-effective catalysts in hydrogen evolution reaction.Herein,we systematically summarize the existing defect engin...Recently,two-dimensional transition metal dichalcogenides(TMDs)demonstrated their great potential as cost-effective catalysts in hydrogen evolution reaction.Herein,we systematically summarize the existing defect engineering strategies,including intrinsic defects(atomic vacancy and active edges)and extrinsic defects(metal doping,nonmetal doping,and hybrid doping),which have been utilized to obtain advanced TMD-based electrocatalysts.Based on theoretical simulations and experimental results,the electronic structure,intermediate adsorption/desorption energies and possible catalytic mechanisms are thoroughly discussed.Particular emphasis is given to the intrinsic relationship between various types of defects and electrocatalytic properties.Furthermore,current opportunities and challenges for mechanical investigations and applications of defective TMD-based catalysts are presented.The aim herein is to reveal the respective properties of various defective TMD catalysts and provide valuable insights for fabricating high-efficiency TMD-based electrocatalysts.展开更多
This work reports the use of defect engineering and carbon supporting to achieve metal-doped phosphides with high activities and stabilities for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OE...This work reports the use of defect engineering and carbon supporting to achieve metal-doped phosphides with high activities and stabilities for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)in alkaline media.Specifically,the nitrogen-doped carbon nanofiber-supported Ni-doped CoP_(3) with rich P defects(Pv·)on the carbon cloth(p-NiCoP/NCFs@CC)is synthesized through a plasma-assisted phosphorization method.The p-NiCoP/NCFs@CC is an efficient and stable catalyst for the HER and the OER.It only needs overpotentials of 107 and 306 mV to drive 100 mA cm^(-2) for the HER and the OER,respectively.Its catalytic activities are higher than those of other catalysts reported recently.The high activities of the p-NiCoP/NCFs@CC mainly arise from its peculiar structural features.The density functional theory calculation indicates that the Pv·richness,the Ni doping,and the carbon supporting can optimize the adsorption of the H atoms at the catalyst surface and promote the strong electronic couplings between the carbon nanofiber-supported p-NiCoP with the surface oxide layer formed during the OER process.This gives the p-NiCoP/NCFs@CC with the high activities for the HER and the OER.When used in alkaline water electrolyzers,the p-NiCoP/NCFs@CC shows the superior activity and excellent stability for overall water splitting.展开更多
The photocatalytic oxygen reduction reaction (ORR), particularly the one-step two-electron (2e−) pathway, is a highly promising strategy for efficient and selective hydrogen peroxide (H_(2)O_(2)) synthesis. However, c...The photocatalytic oxygen reduction reaction (ORR), particularly the one-step two-electron (2e−) pathway, is a highly promising strategy for efficient and selective hydrogen peroxide (H_(2)O_(2)) synthesis. However, constructing efficient photocatalysts to achieve a one-step 2e− ORR process remains a significant challenge. Herein, we developed an efficient photocatalyst by incorporating pyrimidine units into benzotrithiophene-based covalent organic framework (BTT-MD-COF), enabling the photosynthesis of H_(2)O_(2) via the one-step 2e− ORR pathway with O_(2) and water. Under visible-light irradiation, BTT-MD-COF exhibited a high H_(2)O_(2) production rate of up to 5691.2 µmol·h^(−1)·g^(−1). Further experimental results and theoretical studies revealed that the introduction of pyrimidine units accelerates the separation of photoinduced electron–hole pairs and promotes Yeager-type O_(2) adsorption, which alters the two-step 2e− ORR process to the direct one-step 2e− process. This work offers a new avenue to create metal-free catalysts for efficient photosynthesis of H_(2)O_(2).展开更多
Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly aff...Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well understood.Herein,we present the defect engineering of CISe QDs for efficient solar-energy conversion.Lewis acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their morphology.Among them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the QDs.The proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.展开更多
Lithium-rich manganese-based oxides(LRMOs) exhibit high theoretical energy densities, making them a prominent class of cathode materials for lithium-ion batteries. However, the performance of these layered cathodes of...Lithium-rich manganese-based oxides(LRMOs) exhibit high theoretical energy densities, making them a prominent class of cathode materials for lithium-ion batteries. However, the performance of these layered cathodes often declines because of capacity fading during cycling. This decline is primarily attributed to anisotropic lattice strain and oxygen release from cathode surfaces. Given notable structural transformations, complex redox reactions, and detrimental interface side reactions in LRMOs, the development of a single modification approach that addresses bulk and surface issues is challenging. Therefore,this study introduces a surface double-coupling engineering strategy that mitigates bulk strain and reduces surface side reactions. The internal spinel-like phase coating layer, featuring threedimensional(3D) lithium-ion diffusion channels, effectively blocks oxygen release from the cathode surface and mitigates lattice strain. In addition, the external Li_(3)PO_(4) coating layer, noted for its superior corrosion resistance, enhances the interfacial lithium transport and inhibits the dissolution of surface transition metals. Notably, the spinel phase, as excellent interlayer, securely anchors Li_(3)PO_(4) to the bulk lattice and suppresses oxygen release from lattices. Consequently, these modifications considerably boost structural stability and durability, achieving an impressive capacity retention of 83.4% and a minimal voltage decay of 1.49 m V per cycle after 150 cycles at 1 C. These findings provide crucial mechanistic insights into the role of surface modifications and guide the development of high-capacity cathodes with enhanced cyclability.展开更多
Cu-based catalysts are widely employed for CO_(2) hydrogenation to methanol,which is expected as a promising process to achieving carbon neutrality.However,most Cu-based catalysts still suffer from low methanol yield ...Cu-based catalysts are widely employed for CO_(2) hydrogenation to methanol,which is expected as a promising process to achieving carbon neutrality.However,most Cu-based catalysts still suffer from low methanol yield with a passable CO_(2) conversion and lack insight into its reaction mechanism for guiding the design of catalysts.In this work,Cu^(+)/CeZrO_(x) interfaces are engineered by employing a series of ceria-zirconia solid solution catalysts with various Ce/Zr ratios,forming a Cu^(+)-O_(v)-Ce^(3+)structure where Cu^(+)atoms are bonded to the oxygen vacancies(O_(v))of ceria.Compared to Cu/CeO_(2) and Cu/ZrO_(2),the optimized catalyst(i.e.,Cu_(0.3)Ce_(0.3)Zr_(0.7))exhibits a much higher mass-specific methanol formation rate(192g_(MeOH)/kg_(cat)/h)at 240℃and 3 MPa.Through a series of in-situ and ex-situ characterization,it is revealed that oxygen vacancies in solid solutions can effectively assist the activation of CO_(2) and tune the electronic state of copper to promote the formation of Cu^(+)/CeZrO_(x) interfaces,which stabilizes the key*CO intermediate,inhibits its desorption and facilitates its further hydrogenation to methanol via the reverse watergas-shift(RWGS)+CO-Hydro pathway.Therefore,the concentration of*CO or the apparent Cu^(+)/(Cu^(+)+Cu^(0))ratio could be employed as a quantitative descriptor of the methanol formation rate.This work is expected to give a deep insight into the mechanism of metal/support interfaces in CO_(2) hydrogenation to methanol,offering an effective strategy to develop new catalysts with high performance.展开更多
The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,w...The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.展开更多
Seawater splitting is a prospective approach to yield renewable and sustainable hydrogen energy.Complex preparation processes and poor repeatability are currently considered to be an insuperable impediment to the prom...Seawater splitting is a prospective approach to yield renewable and sustainable hydrogen energy.Complex preparation processes and poor repeatability are currently considered to be an insuperable impediment to the promotion of the large-scale production and application of electrocatalysts.Avoiding the use of intricate instruments,corrosion engineering is an intriguing strategy to reduce the cost and presents considerable potential for electrodes with catalytic performance.An anode comprising quinary AlCoCrFeNi layered double hydroxides uniformly decorated on an AlCoCrFeNi high-entropy alloy is proposed in this paper via a one-step corrosion engineering method,which directly serves as a remarkably active catalyst for boosting the oxygen evolution reaction(OER)in alkaline seawater.Notably,the best-performing catalyst exhibited oxygen evolution reaction activity with overpotential values of 272.3 and 332 mV to achieve the current densities of 10 and100 mA·cm^(-2),respectively.The failure mechanism of the obtained catalyst was identified for advancing the development of multicomponent catalysts.展开更多
Cu/ZnO is widely used in the hydrogenation of carbon dioxide (CO_(2)) to methanol (CH_(3)OH) to improve the lowconversion rate and selectivity generally observed. In this work, a series of In, Zr, Co, and Ni-doped CuO...Cu/ZnO is widely used in the hydrogenation of carbon dioxide (CO_(2)) to methanol (CH_(3)OH) to improve the lowconversion rate and selectivity generally observed. In this work, a series of In, Zr, Co, and Ni-doped CuO-ZnO catalysts wassynthesized via a hydrothermal method. By introducing a second metal element, the activity and dispersion of the activesites can be adjusted and the synergy between the metal and the carrier can be enhanced, forming an abundance of oxygenvacancies. Oxygen vacancies not only adsorb CO_(2) but also activate the intermediates in methanol synthesis, playing a keyrole in the entire reaction. Co3O4-CuO-ZnO had the best catalytic performance (a CO_(2) conversion rate of 9.17%;a CH_(3)OHselectivity of 92.77%). This study describes a typical strategy for multi-component doping to construct a catalyst with anabundance of oxygen vacancies, allowing more effective catalysis to synthesize CH_(3)OH from CO_(2).展开更多
Electrochemical reduction of nitrate,a common pollutant in aquatic environment,to valuable ammonia(NO3-RR) using renewably-sourced electricity has attracted widespread interests,with past efforts mainly focused on des...Electrochemical reduction of nitrate,a common pollutant in aquatic environment,to valuable ammonia(NO3-RR) using renewably-sourced electricity has attracted widespread interests,with past efforts mainly focused on designing electrocatalysts with high activity and selectivity.The detailed correlation between catalyst properties and NO3-RR kinetics,nevertheless,is still not fully understood.In this work,we modulate the surface oxygen species of Cu_(2)O via facet engineering,and systematically study the impact of these oxygen species on the NO_(3)^(-)RR activity.Combining advanced spectroscopic techniques,densi ty fu n ctional theory calculations and molecular dynamics simulations,we find that while oxygen vacancies on Cu_(2)O(111) surface promote the adsorption of reactants and reaction intermediates,hydroxyl groups effectively inhibit the side reaction of hydrogen evolution and facilitate the hydrogenation process of NO3-RR.These two effects work in concert to render Cu_(2)O(111) facet the highest NO3-RR activity relative to those from other facets.Our study provides critical insights into the synergistic effect of exposed facets and surface oxygen species on heterogeneous catalysis,and offers a generalizable,facet engineeringbased strategy for improving the performance of a variety of electrocatalysts important for renewable energy conversion.展开更多
The surface properties of catalysts determine the intrinsic activity and adaptability.Ruthenium is regarded as a potential candidate to substitute platinum for water electrolysis due to the low cost and analogous elec...The surface properties of catalysts determine the intrinsic activity and adaptability.Ruthenium is regarded as a potential candidate to substitute platinum for water electrolysis due to the low cost and analogous electronic structures while it suffers from severe dissolution and stability problems.Herein,the modification of Ru/C with atomically dispersed cobalt atoms is achieved via a simple thermal doping method.The newly formed amorphous shell with Ru-Co sites on the Ru/C catalyst improved the hydrogen evolution reaction activity and stability significantly.Impressively,the obtained Co1Ru@Ru/CN_(x)catalyst exhibited an overpotential as low as 30 mV at 10 mA cm^(-2)in an alkaline medium,which is among the best HER catalysts reported so far.The oxygen oxophile Co prevents the fast oxidation and dissolution of Ru species,ensuring outstanding long-term durability up to 70 h.Theoretical calculations reveal that the Ru-Co coordination acts as a more active site for water dissociation than the Ru-Ru.Meanwhile,the"Ru-Co shell/Ru core"structures show high adaptability for the reaction conditions.This simple doping strategy offers prospects for scalable preparation of highly active electrocatalysts.展开更多
Two-dimensional(2D)ferroelectric compounds are a special class of materials that meet the need for devices miniaturization,which can lead to a wide range of applications.Here,we investigate ferroelectric properties of...Two-dimensional(2D)ferroelectric compounds are a special class of materials that meet the need for devices miniaturization,which can lead to a wide range of applications.Here,we investigate ferroelectric properties of monolayer group-IV monochalcogenides MX(M=Sn,Ge;X=Se,Te,S)via strain engineering,and their effects with contaminated hydrogen are also discussed.GeSe,GeTe,and GeS do not go through transition up to the compressive strain of-5%,and consequently have good ferroelectric parameters for device applications that can be further improved by applying strain.According to the calculated ferroelectric properties and the band gaps of these materials,we find that their band gap can be adjusted by strain for excellent photovoltaic applications.In addition,we have determined the most stable hydrogen occupancy location in the monolayer SnS and SnTe.It reveals that H prefers to absorb on SnS and SnTe monolayers as molecules rather than atomic H.As a result,hydrogen molecules have little effect on the polarization and electronic structure of monolayer SnTe and SnS.展开更多
基金supported by the Key Research and Design Program of Qinhuangdao(202101A005)the Science and Technology Project of Hebei Education Department(QN2023094)+2 种基金the Cultivation Project for Basic Research and Innovation of Yanshan University(2021LGQN028)the Project for Research and Development of Metal Catalysts for Photo-thermal Decomposition of Waste Plastics to Prepare Value-added Chemicals(x2023322)the Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(22567616H).
文摘Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on CeO_(2)and Tb-doped CeO_(2)were prepared by a precipitation method.The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,H_(2)temperature programmed reduction,and X-ray photoelectron spectroscopy.The results show that Tb-doped CeO_(2)supported Pt possesses abundant surface oxygen vacancies,good inhibition of ceria sintering,and strong metal-support interaction compared with CeO_(2)supported Pt.The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels(n-dodecane)was tested.Compared with 2Pt/CeO_(2),2Pt/Ce_(0.9)Tb_(0.1)O_(2),and 2Pt/Ce_(0.5)Tb_(0.5)O_(2),the 2Pt/Ce_(0.7)Tb_(0.3)O_(2)has higher activity and stability for hydrogen production,on which the conversion of n-dodecane was maintained at about 53.2%after 600 min reaction under 700℃at liquid space velocity of 9 ml·g^(-1)·h^(-1).2Pt/CeO_(2)rapidly deactivated,the conversion of n-dodecane was reduced to only 41.6%after 600 min.
基金National Natural Science Foundation of China (Nos. 22078242 and U20A20153)Applied Basic Research Program of Yunnan Province (Nos. 202101BE070001-032 and 202101BH070002)。
文摘Fe-N-C catalysts are widely considered as promising non-precious-metal candidates for electrocatalytic oxygen reduction reaction(ORR),Yet despite their high catalytic activity through rational modulation,challenges remain in their low site density and unsatisfactory mass transfer structure.Herein,we present a structural engineering approach employing a soft-template coating strategy to fabricate a hollow and hierarchically porous N-doped carbon framework anchored with atomically dispersed Fe sites(FeNCh) as an efficient ORR catalyst.The combination of hierarchical porosity and high exterior surface area is proven crucial for exposing more active sites,which gives rise to a remarkable ORR performance with a half-wave potential of 0.902 V in 0.1 m KOH and 0.814 V in 0.1 m HClO_(4),significantly outperforming its counterpart with solid structure and dominance of micropores(FeNC-s).The mass transfer property is revealed by in-situ electrochemical impedance spectroscopy(EIS) measurement.The distribution of relaxation time(DRT) analysis is further introduced to deconvolve the kinetic and mass transport processes,which demonstrates an alleviated mass transport resistance for FeNC-h,validating the effectiveness of structural engineering.This work not only provides an effective structural engineering approach but also contributes to the comprehensive mass transfer evaluation on advanced electrocatalyst for energy conversion applications.
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.51972024)the Natural Science Foundation of Guangdong Province(No.2022A1515010185).
文摘Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further to synthesize heterogeneous catalyst with highly dispersed RuNi nanoparticles (Ru1Ni1.5@UiO-66(Ce)-12 h). The construction of Ce-O-Ru/Ni heterogeneous interfaces and Ni–Ru bonds provide electron transfer channels from Ce-oxo clusters and Ni species to Ru species. Furthermore, the microenvironment and electronic structure of Ru0 active sites were synergistically regulated by adjusting the content of metal-organic frameworks (MOFs) defects and Ni promoter, thereby enhancing the adsorption and activation ability of H–H and C=C bonds. Therefore, Ru1Ni1.5@UiO-66(Ce)-12 h achieved dicyclopentadiene saturated hydrogenation (100% conversion) to tetrahydrodicyclopentadiene (∼ 100% selectivity) under mild condition (35℃, 1 MPa) with only 25 min. Meanwhile, the sample exhibited excellent structural stability after 6 cycles test. This study provides a promising strategy for the rational design of remarkable noble metal-based catalysts for practical applications.
基金support from the National Natural Science Foundation of China(No.22005147)Dr.You acknowledges the financial support from the National Key Research and Development Program of China(2021YFA1600800)+1 种基金the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage(HUST),Ministry of Education(2021JYBKF03).
文摘The electrocatalytic water splitting technology can generate highpurity hydrogen without emitting carbon dioxide,which is in favor of relieving environmental pollution and energy crisis and achieving carbon neutrality.Electrocatalysts can effectively reduce the reaction energy barrier and increase the reaction efficiency.Facet engineering is considered as a promising strategy in controlling the ratio of desired crystal planes on the surface.Owing to the anisotropy,crystal planes with different orientations usually feature facet-dependent physical and chemical properties,leading to differences in the adsorption energies of oxygen or hydrogen intermediates,and thus exhibit varied electrocatalytic activity toward hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In this review,a brief introduction of the basic concepts,fundamental understanding of the reaction mechanisms as well as key evaluating parameters for both HER and OER are provided.The formation mechanisms of the crystal facets are comprehensively overviewed aiming to give scientific theory guides to realize dominant crystal planes.Subsequently,three strategies of selective capping agent,selective etching agent,and coordination modulation to tune crystal planes are comprehensively summarized.Then,we present an overview of significant contributions of facet-engineered catalysts toward HER,OER,and overall water splitting.In particular,we highlight that density functional theory calculations play an indispensable role in unveiling the structure–activity correlation between the crystal plane and catalytic activity.Finally,the remaining challenges in facet-engineered catalysts for HER and OER are provided and future prospects for designing advanced facet-engineered electrocatalysts are discussed.
基金the support from the National Key Research&Development Program(2022YFB3803700)of ChinaNational Natural Science Foundation(No.52171186)the financial support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling stability.Impressively,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 min.Moreover,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption properties.Notably,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.
基金financially supported by National Natural Science Foundation of China(No.22209049,22075102,22005120)Natural Science Foundation of Guangdong Province(No.2023A1515012804)Fundamental Research Funds for the Central Universities(No.2022ZYGXZR048)。
文摘Nickel-based materials,including metallic Ni and Ni oxide,have been widely studied in the exploration of non-precious-metal hydrogen electrocatalysts,but neither pure Ni nor NiO is ideal for the hydrogen evolution reaction(HER)and hydrogen oxidation reaction(HOR).In this paper,an oxygen insertion strategy was applied on nickel to regulate its hydrogen electrocatalytic performance,and the oxygen-inserted nickel catalyst was successfully obtained with the assistance of tungsten dioxide support(denoted as O-Ni/WO_(2)).The partial insertion of oxygen in Ni maintains the face-centered cubic arrangement of Ni atoms,simultaneously expanding the lattice and increasing the lattice spacing.Consequently,the adsorption strength of^(*)H and^(*)OH on Ni is optimized,thus resulting in superior electrocatalytic performance of0-Ni/WO_(2)in alkaline HER/HOR.The Tafel slope of O-Ni/WO_(2)@NF for HER is 56 mV dec^(-1),and the kinetic current density of O-Ni/WO_(2)for HOR reaches 4.85 mA cm^(-2),which is ahead of most currently reported catalysts.Our proposed strategy of inserting an appropriate amount of anions into the metal lattice could provide more possibilities for the design of high-performance catalysts.
基金supported by the National Natural Science Foundation of China(No.52171022,No.22105214)Zhejiang Provincial Natural Science Foundation of China(Grant No.LXR22B030001)+3 种基金Fujian Institute of Innovation and Chinese Academy of Sciences.K.C.Wong Education Foundation(GJTD-2019-13)the National Key Research and Development Program of China(2019YFB2203400)Ningbo Yongjiang Talent Introduction Programme(2021A-036-B)NingBo S&T Innovation 2025 Major Special Programme(No:2020z059)and the“111 Project”(B20030).
文摘Oxygenated carbon materials exhibit outstanding electrocatalytic performance in the production of hydrogen peroxide(H2O2)through a two-electron oxygen reduction reaction.The nature of the active functional group and underlying reaction mechanism,however,remain unclear.Here,a comprehensive workflow was established to identify the active sites from the numerous possible structures.The common hydroxyl group at the notched edge demonstrates a key role in the two-electron process.The local chemical environment weakens the binding of OOH intermediate to substrate while enhancing interaction with solution,thereby promoting the H_(2)O_(2)production.With increasing pH,the intramolecular hydrogen bond between OOH intermediate and hydroxyl decreases,facilitating OOH desorption.Furthermore,the rise in selectivity with increasing potential stems from the suppression of the four-electron process.The active site was further validated through experiments.Guided by theoretical understanding,optimal performance was achieved with high selectivity(>95%)and current density(2.06 mA/cm^(2))in experiment.
基金supported by the National Key Research and Development Program of China(2020YFA0908200)the National Natural Science Foundation of China(T2225003,52073060,and 61927805)+3 种基金the Nanjing Medical Science and Technique Development Foundation(ZKX21019)the Clinical Trials from Nanjing Drum Tower Hospital(2022-LCYJ-ZD-01)the Guangdong Basic and Applied Basic Research Foundation(2021B1515120054)the Shenzhen Fundamental Research Program(JCYJ20190813152616459 and JCYJ20210324133214038).
文摘Microparticles have demonstrated value for regenerative medicine.Attempts in this field tend to focus on the development of intelligent multifunctional microparticles for tissue regeneration.Here,inspired by erythrocytes-associated self-repairing process in damaged tissue,we present novel biomimetic erythrocyte-like microparticles(ELMPs).These ELMPs,which are composed of extracellular matrix-like hybrid hydrogels and the functional additives of black phosphorus,hemoglobin,and growth factors(GFs),are generated by using a microfluidic electrospray.As the resultant ELMPs have the capacity for oxygen delivery and near-infrared-responsive release of both GFs and oxygen,they would have excellent biocompatibility and multifunctional performance when serving as microscaffolds for cell adhesion,stimulating angiogenesis,and adjusting the release profile of cargoes.Based on these features,we demonstrate that the ELMPs can stably overlap to fill a wound and realize controllable cargo release to achieve the desired curative effect of tissue regeneration.Thus,we consider our biomimetic ELMPs with discoid morphology and cargo-delivery capacity to be ideal for tissue engineering.
基金National Natural Science Foundation of China,Grant/Award Numbers:51874039,52103333University of Science and Technology Beijing,talent program,Grant/Award Number:06500167Major Science and Technology Project,Grant/Award Number:2017ZX07402001。
文摘Recently,two-dimensional transition metal dichalcogenides(TMDs)demonstrated their great potential as cost-effective catalysts in hydrogen evolution reaction.Herein,we systematically summarize the existing defect engineering strategies,including intrinsic defects(atomic vacancy and active edges)and extrinsic defects(metal doping,nonmetal doping,and hybrid doping),which have been utilized to obtain advanced TMD-based electrocatalysts.Based on theoretical simulations and experimental results,the electronic structure,intermediate adsorption/desorption energies and possible catalytic mechanisms are thoroughly discussed.Particular emphasis is given to the intrinsic relationship between various types of defects and electrocatalytic properties.Furthermore,current opportunities and challenges for mechanical investigations and applications of defective TMD-based catalysts are presented.The aim herein is to reveal the respective properties of various defective TMD catalysts and provide valuable insights for fabricating high-efficiency TMD-based electrocatalysts.
基金supports from the Zhejiang Provincial Natural Science Foundation(No.LR22E070001)the National Natural Science Foundation of China(Nos.12275239 and 11975205)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515120048)the Fundamental Research Funds of Zhejiang Sci-Tech University(No.23062096-Y).
文摘This work reports the use of defect engineering and carbon supporting to achieve metal-doped phosphides with high activities and stabilities for the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)in alkaline media.Specifically,the nitrogen-doped carbon nanofiber-supported Ni-doped CoP_(3) with rich P defects(Pv·)on the carbon cloth(p-NiCoP/NCFs@CC)is synthesized through a plasma-assisted phosphorization method.The p-NiCoP/NCFs@CC is an efficient and stable catalyst for the HER and the OER.It only needs overpotentials of 107 and 306 mV to drive 100 mA cm^(-2) for the HER and the OER,respectively.Its catalytic activities are higher than those of other catalysts reported recently.The high activities of the p-NiCoP/NCFs@CC mainly arise from its peculiar structural features.The density functional theory calculation indicates that the Pv·richness,the Ni doping,and the carbon supporting can optimize the adsorption of the H atoms at the catalyst surface and promote the strong electronic couplings between the carbon nanofiber-supported p-NiCoP with the surface oxide layer formed during the OER process.This gives the p-NiCoP/NCFs@CC with the high activities for the HER and the OER.When used in alkaline water electrolyzers,the p-NiCoP/NCFs@CC shows the superior activity and excellent stability for overall water splitting.
基金financially supported by the Nation Key Research and Development(R&D)Program of China(No.2022YFB3603804)Natural Science Foundation of Shanghai(No.22ZR1407800).
文摘The photocatalytic oxygen reduction reaction (ORR), particularly the one-step two-electron (2e−) pathway, is a highly promising strategy for efficient and selective hydrogen peroxide (H_(2)O_(2)) synthesis. However, constructing efficient photocatalysts to achieve a one-step 2e− ORR process remains a significant challenge. Herein, we developed an efficient photocatalyst by incorporating pyrimidine units into benzotrithiophene-based covalent organic framework (BTT-MD-COF), enabling the photosynthesis of H_(2)O_(2) via the one-step 2e− ORR pathway with O_(2) and water. Under visible-light irradiation, BTT-MD-COF exhibited a high H_(2)O_(2) production rate of up to 5691.2 µmol·h^(−1)·g^(−1). Further experimental results and theoretical studies revealed that the introduction of pyrimidine units accelerates the separation of photoinduced electron–hole pairs and promotes Yeager-type O_(2) adsorption, which alters the two-step 2e− ORR process to the direct one-step 2e− process. This work offers a new avenue to create metal-free catalysts for efficient photosynthesis of H_(2)O_(2).
基金the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(grant nos.2021R1C1C1007844,2021M3I3A1085039,2020R1F1A1061505,and 2020R1C1C1012014).
文摘Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well understood.Herein,we present the defect engineering of CISe QDs for efficient solar-energy conversion.Lewis acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their morphology.Among them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the QDs.The proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.
基金National Natural Science Foundation of China (22179008, 21875022)Yibin ‘Jie Bang Gua Shuai’ (2022JB004)+3 种基金support from the Beijing Nova Program (20230484241)support from the Postdoctoral Fellowship Program of CPSF (GZB20230931)Special Support of the Chongqing Postdoctoral Research Project (2023CQBSHTB2041)Initial Energy Science & Technology Co., Ltd (IEST)。
文摘Lithium-rich manganese-based oxides(LRMOs) exhibit high theoretical energy densities, making them a prominent class of cathode materials for lithium-ion batteries. However, the performance of these layered cathodes often declines because of capacity fading during cycling. This decline is primarily attributed to anisotropic lattice strain and oxygen release from cathode surfaces. Given notable structural transformations, complex redox reactions, and detrimental interface side reactions in LRMOs, the development of a single modification approach that addresses bulk and surface issues is challenging. Therefore,this study introduces a surface double-coupling engineering strategy that mitigates bulk strain and reduces surface side reactions. The internal spinel-like phase coating layer, featuring threedimensional(3D) lithium-ion diffusion channels, effectively blocks oxygen release from the cathode surface and mitigates lattice strain. In addition, the external Li_(3)PO_(4) coating layer, noted for its superior corrosion resistance, enhances the interfacial lithium transport and inhibits the dissolution of surface transition metals. Notably, the spinel phase, as excellent interlayer, securely anchors Li_(3)PO_(4) to the bulk lattice and suppresses oxygen release from lattices. Consequently, these modifications considerably boost structural stability and durability, achieving an impressive capacity retention of 83.4% and a minimal voltage decay of 1.49 m V per cycle after 150 cycles at 1 C. These findings provide crucial mechanistic insights into the role of surface modifications and guide the development of high-capacity cathodes with enhanced cyclability.
基金sponsored by the National Natural Science Foundation of China(21808120,21978148)。
文摘Cu-based catalysts are widely employed for CO_(2) hydrogenation to methanol,which is expected as a promising process to achieving carbon neutrality.However,most Cu-based catalysts still suffer from low methanol yield with a passable CO_(2) conversion and lack insight into its reaction mechanism for guiding the design of catalysts.In this work,Cu^(+)/CeZrO_(x) interfaces are engineered by employing a series of ceria-zirconia solid solution catalysts with various Ce/Zr ratios,forming a Cu^(+)-O_(v)-Ce^(3+)structure where Cu^(+)atoms are bonded to the oxygen vacancies(O_(v))of ceria.Compared to Cu/CeO_(2) and Cu/ZrO_(2),the optimized catalyst(i.e.,Cu_(0.3)Ce_(0.3)Zr_(0.7))exhibits a much higher mass-specific methanol formation rate(192g_(MeOH)/kg_(cat)/h)at 240℃and 3 MPa.Through a series of in-situ and ex-situ characterization,it is revealed that oxygen vacancies in solid solutions can effectively assist the activation of CO_(2) and tune the electronic state of copper to promote the formation of Cu^(+)/CeZrO_(x) interfaces,which stabilizes the key*CO intermediate,inhibits its desorption and facilitates its further hydrogenation to methanol via the reverse watergas-shift(RWGS)+CO-Hydro pathway.Therefore,the concentration of*CO or the apparent Cu^(+)/(Cu^(+)+Cu^(0))ratio could be employed as a quantitative descriptor of the methanol formation rate.This work is expected to give a deep insight into the mechanism of metal/support interfaces in CO_(2) hydrogenation to methanol,offering an effective strategy to develop new catalysts with high performance.
基金support from several sources,including the Backbone Teacher Training Program(10912-SJGG2021-04233)the Teaching Reform Project of Chengdu University of Technology(JG2130131)+1 种基金the University-Industry Collaborative Education Project,Ministry of Education,China(22097130210756)National Natural Science Foundation of China(42272129).
文摘The Yueguang gold deposit is located in Fengjia,Xinhua County,Hunan Province,South China.It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt,west of the Baimashan granitic batholith.In order to discern the characteristics of the ore-formingfluids,the underlying mineralization processes,and establish a foundation for the origin of the Yueguang gold depositfluid inclusion micro-thermometry,as well as quartz hydrogen and oxygen isotope analysis,have been carried out on samples obtained from various stages of mineralization.The hydrothermal miner-alization stages within the Yueguang gold deposit can be categorized into three stages:(i)the barren,pre-ore quartz-pyrite stage(Stage Ⅰ),the quartz-pyrite-gold stage(Stage Ⅱ),and the post-ore quartz-carbonate stage(Stage Ⅲ),with the second stage being the main mineralization stage.Thefluid inclusions identified in samples from the main min-eralization stage can predominantly be described with the NaCl–H_(2)O and CO_(2)–NaCl–H_(2)O systems.These inclusions display homogenization temperatures ranging from 158.8 to 334.9℃,and thefluid salinity ranges from 0.3%to 4.0%(wt.%NaCl equiv.).Laser Raman spectroscopy analysis of individual inclusions further reveals the presence of gas-phases such as CO_(2),CH_(4),and N_(2).Isotopic analysis indicatesδ^(18)Ofluid values ranging from 3.95 to 6.7‰ and δDH_(2)O values ranging from-71.9 to-55.7‰.These results indi-cate that the ore-formingfluid of the Yueguang gold deposit belongs to metamorphic hydrothermalfluids of middle-low temperature and low salinity.In the process of ore formation,gold is transported in the form of Au(HS)2-complexes,with gold deposition being driven byfluid immiscibility.Therefore,the Yueguang gold deposit is categorized as an orogenic gold deposit dominated by metamorphic hydrother-malfluid.It may become a new target for gold exploration in the Baimashan region,central Hunan Province.
基金supported by the National Natural Science Foundation of China (No.51901018)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology (YESS,2019QNRC001)+1 种基金the Natural Science Foundation of Beijing Municipality (No.2212037)the National Science and Technology Resources Investigation Program of China (No.2019FY 101400)。
文摘Seawater splitting is a prospective approach to yield renewable and sustainable hydrogen energy.Complex preparation processes and poor repeatability are currently considered to be an insuperable impediment to the promotion of the large-scale production and application of electrocatalysts.Avoiding the use of intricate instruments,corrosion engineering is an intriguing strategy to reduce the cost and presents considerable potential for electrodes with catalytic performance.An anode comprising quinary AlCoCrFeNi layered double hydroxides uniformly decorated on an AlCoCrFeNi high-entropy alloy is proposed in this paper via a one-step corrosion engineering method,which directly serves as a remarkably active catalyst for boosting the oxygen evolution reaction(OER)in alkaline seawater.Notably,the best-performing catalyst exhibited oxygen evolution reaction activity with overpotential values of 272.3 and 332 mV to achieve the current densities of 10 and100 mA·cm^(-2),respectively.The failure mechanism of the obtained catalyst was identified for advancing the development of multicomponent catalysts.
基金the National Natural Science Foundation of China(Nos.61973223,51972306)the Liao Ning Revitalization Talents Program(No.XLYC2007051)+2 种基金the Liaoning Educational Department Foundation(No.LJKMZ20220762,JYTMS20231510)the Natural Science Foundation of Liaoning Province(No.2023-MS-235,2023-MSLH-270)the Key Project in Science&Technology of SYUCT(No.2023DB005).
文摘Cu/ZnO is widely used in the hydrogenation of carbon dioxide (CO_(2)) to methanol (CH_(3)OH) to improve the lowconversion rate and selectivity generally observed. In this work, a series of In, Zr, Co, and Ni-doped CuO-ZnO catalysts wassynthesized via a hydrothermal method. By introducing a second metal element, the activity and dispersion of the activesites can be adjusted and the synergy between the metal and the carrier can be enhanced, forming an abundance of oxygenvacancies. Oxygen vacancies not only adsorb CO_(2) but also activate the intermediates in methanol synthesis, playing a keyrole in the entire reaction. Co3O4-CuO-ZnO had the best catalytic performance (a CO_(2) conversion rate of 9.17%;a CH_(3)OHselectivity of 92.77%). This study describes a typical strategy for multi-component doping to construct a catalyst with anabundance of oxygen vacancies, allowing more effective catalysis to synthesize CH_(3)OH from CO_(2).
基金supported by the Guangdong Provincial Natural Science Foundation,China(2021A1515012330)the National Natural Science Foundation of China(11975102)+2 种基金the State Key Laboratory of Pulp and Paper Engineering(2022PY03)the Guangdong Pearl River Talent Program,China(2017GC010281)supported by ME2 project under contract from the National Natural Science Foundation of China(11227902)。
文摘Electrochemical reduction of nitrate,a common pollutant in aquatic environment,to valuable ammonia(NO3-RR) using renewably-sourced electricity has attracted widespread interests,with past efforts mainly focused on designing electrocatalysts with high activity and selectivity.The detailed correlation between catalyst properties and NO3-RR kinetics,nevertheless,is still not fully understood.In this work,we modulate the surface oxygen species of Cu_(2)O via facet engineering,and systematically study the impact of these oxygen species on the NO_(3)^(-)RR activity.Combining advanced spectroscopic techniques,densi ty fu n ctional theory calculations and molecular dynamics simulations,we find that while oxygen vacancies on Cu_(2)O(111) surface promote the adsorption of reactants and reaction intermediates,hydroxyl groups effectively inhibit the side reaction of hydrogen evolution and facilitate the hydrogenation process of NO3-RR.These two effects work in concert to render Cu_(2)O(111) facet the highest NO3-RR activity relative to those from other facets.Our study provides critical insights into the synergistic effect of exposed facets and surface oxygen species on heterogeneous catalysis,and offers a generalizable,facet engineeringbased strategy for improving the performance of a variety of electrocatalysts important for renewable energy conversion.
基金support from the National Natural Science Foundation of China(21802120,21872121,and 21908189)the National Key R&D Program of China(2016YFA0202900)+3 种基金the Key R&D Project of Zhejiang Province(2020C01133)the Fundamental Research Funds for the Central Universities(G2019KY05119)the China Postdoctoral Science Foundation(2021 M692634)the Natural Science Basic Research Program of Shaanxi Province(2022JQ-118)are greatly appreciated.
文摘The surface properties of catalysts determine the intrinsic activity and adaptability.Ruthenium is regarded as a potential candidate to substitute platinum for water electrolysis due to the low cost and analogous electronic structures while it suffers from severe dissolution and stability problems.Herein,the modification of Ru/C with atomically dispersed cobalt atoms is achieved via a simple thermal doping method.The newly formed amorphous shell with Ru-Co sites on the Ru/C catalyst improved the hydrogen evolution reaction activity and stability significantly.Impressively,the obtained Co1Ru@Ru/CN_(x)catalyst exhibited an overpotential as low as 30 mV at 10 mA cm^(-2)in an alkaline medium,which is among the best HER catalysts reported so far.The oxygen oxophile Co prevents the fast oxidation and dissolution of Ru species,ensuring outstanding long-term durability up to 70 h.Theoretical calculations reveal that the Ru-Co coordination acts as a more active site for water dissociation than the Ru-Ru.Meanwhile,the"Ru-Co shell/Ru core"structures show high adaptability for the reaction conditions.This simple doping strategy offers prospects for scalable preparation of highly active electrocatalysts.
基金the National Natural Science Foundation of China(NSFC)(Grant No.12074126)the Foundation for Innovative Research Groups of NSFC(Grant No.51621001)the Fundamental Research Funds for the Central Universities(Grant No.2020ZYGXZR076).
文摘Two-dimensional(2D)ferroelectric compounds are a special class of materials that meet the need for devices miniaturization,which can lead to a wide range of applications.Here,we investigate ferroelectric properties of monolayer group-IV monochalcogenides MX(M=Sn,Ge;X=Se,Te,S)via strain engineering,and their effects with contaminated hydrogen are also discussed.GeSe,GeTe,and GeS do not go through transition up to the compressive strain of-5%,and consequently have good ferroelectric parameters for device applications that can be further improved by applying strain.According to the calculated ferroelectric properties and the band gaps of these materials,we find that their band gap can be adjusted by strain for excellent photovoltaic applications.In addition,we have determined the most stable hydrogen occupancy location in the monolayer SnS and SnTe.It reveals that H prefers to absorb on SnS and SnTe monolayers as molecules rather than atomic H.As a result,hydrogen molecules have little effect on the polarization and electronic structure of monolayer SnTe and SnS.