Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculate...Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.展开更多
The alkaline zinc-based batteries with high energy density are becoming a research hotspot.However,the poor cycle stability and low-rate performance limit their wide application.Herein,ultra-thin CoNiO2 nanosheet with...The alkaline zinc-based batteries with high energy density are becoming a research hotspot.However,the poor cycle stability and low-rate performance limit their wide application.Herein,ultra-thin CoNiO2 nanosheet with rich oxygen defects anchored on the vertically arranged Ni nanotube arrays(Od-CNO@Ni NTs)is used as a positive material for rechargeable alkaline Ni–Zn batteries.As the highly uniform Ni nanotube arrays provide a fast electron/ion transport path and abundant active sites,the Od-CNO@Ni NTs electrode delivers excellent capacity(432.7 mAh g^(−1))and rate capability(218.3 mAh g^(−1) at 60 A g^(−1)).Moreover,our Od-CNO@Ni NTs//Zn battery is capable of an ultra-long lifespan(93.0%of initial capacity after 5000 cycles),extremely high energy density of 547.5 Wh kg^(−1) and power density of 92.9 kW kg^(−1)(based on the mass of cathode active substance).Meanwhile,the theoretical calculations reveal that the oxygen defects can enhance the interaction between electrode surface and electrolyte ions,contributing to higher capacity.This work opens a reasonable idea for the development of ultra-durable,ultra-fast,and high-energy Ni–Zn battery.展开更多
The great challenges are remained in constructing graphite-based anode with well built-in structures to accelerate kinetics and enhance stability in the advanced K-ion batteries(KIBs).Here,we firstly report the design...The great challenges are remained in constructing graphite-based anode with well built-in structures to accelerate kinetics and enhance stability in the advanced K-ion batteries(KIBs).Here,we firstly report the design of expanded graphite cohered by N,B bridge-doping carbon patches(NBEG)for efficient K-ion adsorption/diffusion and long-term durability.It is the B co-doping that plays a crucial role in maximizing doping-site utilization of N atoms,balancing the adsorption-diffusion kinetics,and promoting the charge transfer between NBEG and K ions.Especially,the robust lamellar structure,suitable interlayer distance,and rich active sites of the designed NBEG favor the rapid ion/electron transfer pathways and high K-ion storage capacity.Consequently,even at a low N,B doping concentration(4.36 at%,2.07 at%),NBEG anode shows prominent electrochemical performance for KIBs,surpassing most of the advanced carbon-based anodes.Kinetic studies,density functional theory simulations,and in-situ Raman spectroscopy are further performed to reveal the K-ion storage mechanism and confirm the critical actions of co-doping B.This work offers the new methods for graphite-electrode design and the deeper insights into their energy storage mechanisms in KIBs.展开更多
We discussed the oxidation differential and mechanisms on different planes of pyrite. The experimental results show that the oxidation priority is:(222) plane>(200) plane>(200) plane, and there is no direct corr...We discussed the oxidation differential and mechanisms on different planes of pyrite. The experimental results show that the oxidation priority is:(222) plane>(200) plane>(200) plane, and there is no direct correlation between the crystal plane index, the atom numbers, and the oxidation priority. However, with more exchanged charge among atoms, the oxidation could be conducted more easily, and the distribution rule of the electric charge conforms with the variation trend of adsorption energy, which will provide more overall cognition on the oxidation mechanism of pyrite from the atomic scale.展开更多
First principles calculation is performed to study the co-adsorption behaviors of O_(2)and CO_(2)onδ-Pu(100)surface by using a slab model within the framework of density functional theory(DFT).The results demonstrate...First principles calculation is performed to study the co-adsorption behaviors of O_(2)and CO_(2)onδ-Pu(100)surface by using a slab model within the framework of density functional theory(DFT).The results demonstrate that the most favorable co-adsorption configurations are T_(v)-C_(4)O_(7)and T_(p1)-C_(2)O_(8),with adsorption energy of-17.296 e V and-23.131 e V for CO_(2)-based and O_(2)-based system,respectively.The C and O atoms mainly interact with the Pu surface atoms.Furthermore,the chemical bonding between C/O and Pu atom is mainly of ionic state,and the reaction mechanism is that C 2 s,C 2 p,O 2s,and O 2p orbitals overlap and hybridize with Pu 6 p,Pu 6 d,and Pu 5 f orbital,resulting in the occurrence of new band structure.The adsorption and dissociation of CO_(2)molecule are obviously promoted by preferentially occupying adsorbed O atoms,therefore,a potential CO_(2)protection mechanism for plutonium-based materials is that in CO_(2)molecule there occurs complete dissociation of CO_(2)→C+O+O,then the dissociated C atom combines with O atom from O_(2)dissociation and produces CO,which will inhibit the O_(2)from further oxidizing Pu surface,and slow down the corrosion rate of plutoniumbased materials.展开更多
Although a few pristine metal-organic frameworks(MOFs) of graphene analogue topology exhibit high intrinsic electrical conductivity, their use in lithium-ion batteries(LIBs) is still hampered by unfavorable Li+adsorpt...Although a few pristine metal-organic frameworks(MOFs) of graphene analogue topology exhibit high intrinsic electrical conductivity, their use in lithium-ion batteries(LIBs) is still hampered by unfavorable Li+adsorption energy(ΔEa). In this paper, an electroconductive ferrocene-based MOF@MXene heterostructure is built to provide stable anodes for Li+storage. Charge density difference and planar average potential charge density show substantial redistribution of charges at the interfaces, transferring from MXene to MOF layers. Moreover, density functional theory(DFT) calculations reveal that the interaction between MXene and MOF significantly increases the ΔEa. As a result, the heterostructure anode exhibits high capacities and outstanding cycling stability with a capacity retention of 80% after 5000 cycles at 5 A g^(-1), outperforming mono-component MXene and MOF. Furthermore, the heterostructure anode is built into a full cell with a commercial NCM 532 cathode, delivering a high energy density of 611 Wh kg^(-1)and power density of 7600 W kg^(-1). The developed conductive MOF@MXene heterogeneity for improved LIB offers valuable insights into the design of advanced electrode materials for energy storage.展开更多
Uncontrollable Li dendrite growth and infinite volume fluctuation during durative plating and stripping process gravely hinder the application of metallic Li electrode in lithium-oxygen batteries.Herein,oxygen vacancy...Uncontrollable Li dendrite growth and infinite volume fluctuation during durative plating and stripping process gravely hinder the application of metallic Li electrode in lithium-oxygen batteries.Herein,oxygen vacancy-rich TiO_(2)(Vo-TiO_(2))nanoparticles(NPs)uniformly dispersing on Ti_(3)C_(2)T_(x)(Vo-TiO_(2)/Ti_(3)C_(2) T_(x))with excellent lithiophilicity feature are presented as effective composite anodes,on which a dense and uniform Li growth behavior is observed.Based on electrochemical studies,mutiphysics simulation and theoretical calculation,it is found that Vo-TiO_(2) coupling with three dimensional(3 D)conductive Ti_(3)C_(2) T_(x) MXene forms highly ordered lithiophilic sites which succeed in guiding Li ions flux and adsorption,thus modulating the uniform Li nucleation and growth.As a result,this composite electrode is capable of preserving Li with high areal capacity of~10 mAh cm^(-2) without the presence of dendrites and large volume expansion.Consequently,the as-prepared Vo-TiO_(2)/Ti_(3)C_(2) T_(x)@Li anode shows outstanding performance including low voltage hysteresis(~19 mV)and superior durability(over 750 h).When assembling with the Vo-TiO_(2)/Ti_(3)C_(2) T_(x)@Li anodes,lithium-oxygen batteries also deliver enhanced cycling stability and improved rate performance.This work demonstrates the effectiveness of oxygen vacancies in guiding Li nucleating and plating behavior at initial stage and brings a promising strategy for promoting the development of advanced Li metal-based batteries.展开更多
Beryllium carbide is used in inertial confinement fusion(ICF)capsule ablation material due to its low atomic number,low opacity,and high melting point properties.We used the method of climbing image nudged elastic ban...Beryllium carbide is used in inertial confinement fusion(ICF)capsule ablation material due to its low atomic number,low opacity,and high melting point properties.We used the method of climbing image nudged elastic band(CINEB)to calculate the diffusion barrier of copper atom in the crystal of beryllium and beryllium carbide.The diffusion barrier of copper atom in crystal beryllium is only 0.79 eV,and the barrier in beryllium carbide is larger than 2.85 eV.The three structures of beryllium carbide:anti-fluorite Be2C,Be2C-Ⅰ,and Be2C-Ⅲhave a good blocking effect to the diffusion of copper atom.Among them,the Be2C-Ⅲstructure has the highest diffusion barrier of 6.09 eV.Our research can provide useful help for studying Cu diffusion barrier materials.展开更多
With the increase of hard disk storage density,the flying height of magnetic head sliders has become lower in recent years,which makes it easier for lubricant materials to transfer between the magnetic head and disk.T...With the increase of hard disk storage density,the flying height of magnetic head sliders has become lower in recent years,which makes it easier for lubricant materials to transfer between the magnetic head and disk.The ability for lubricant materials to transfer is not only related to the operating conditions of disk but also related to the types of lubricant materials(Perfluoropolyether,PFPE)and diamond⁃like carbon(DLC)coating applied to the disk.Based on the principle of molecular dynamics,this study established the adsorption models on disks with different carbon content and the diffusion models of several common PFPE molecules in air.Besides,the adsorption energy and the diffusion coefficients of different models were calculated.Furthermore,the molecular weight,the molecular structure,the lubricant materials end functional groups,and the disks carbon content were found to have influence on the transfer ability of lubricant materials.In particular,the latter two factors have further influence.展开更多
Herein,we prepare the unique hierarchical polypyrrole@cobalt sulfide(PPy-hs@CoS)hollow sphere-based nanofilms as interdigitated electrodes for flexible on-chip micro-supercapacitors(MSC).Benefiting from the excellent ...Herein,we prepare the unique hierarchical polypyrrole@cobalt sulfide(PPy-hs@CoS)hollow sphere-based nanofilms as interdigitated electrodes for flexible on-chip micro-supercapacitors(MSC).Benefiting from the excellent flexibility and high electrical conductivity of PPy-hs combined with the great electrochemical activity of CoS,such PPy-hs@CoS composite material can not only inhibit the volume expansion of PPy but also promote the diffusion of the electrolyte ions.The PPy-hs@CoS filmbased electrode delivers a greatly improved specific capacitance and small resistance.Density functional theory calculations infer that OH−prefers to bind to PPy on CoS@PPy and confirms the synergistic effect of each component for enhanced reaction kinetics.A quasi-solid-state on-chip flexible asymmetric MSC based on PPy-hs@CoS and activated carbon(AC)microelectrodes exhibits large areal-specific capacitance(131.9 mF/cm2 at 0.3 mA/cm2),ultrahigh energy density(0.041 mWh/cm2@0.224 mW/cm2 and 25.6 mWh/cm3@140.6 mW/cm3),and long cycle lifespan.We demonstrate the possibility to scale up the PPy-hs@CoS nanofilm microelectrode by arranging two of our asymmetric MSC in series and parallel connections,which respectively increase the output voltage and current.A self-charging system by connecting our asymmetric MSCs with a piece of commercial solar cells is developed as a potential possible mode for future highly durable and high-voltage integrated electronics.展开更多
The Au(100)surface has been a subject of intense studies due to excellent catalytic activities and its model character for surface science.However,the spontaneous surface reconstruction buries active Au(100)plane and ...The Au(100)surface has been a subject of intense studies due to excellent catalytic activities and its model character for surface science.However,the spontaneous surface reconstruction buries active Au(100)plane and limits practical applications,how to controllably eliminate the surface reconstruction over large scale remains challenging.Here,we experimentally and theoretically demonstrate that simple decoration of the Au(100)surface by tellurium(Te)atoms can uniquely lift its reconstruction over large scale.Scanning tunneling microscopy imaging reveals that the lifting of surface reconstruction preferentially starts from the boundaries of distinct domains and then extends progressively into the domains with the reconstruction rows perpendicular to the boundaries,leaving a Au(100)-(1×1)surface behind.The Au(100)-(1×1)is saturated at~84%±2%with respect to the whole surface at a Te coverage of 0.16 monolayer.With further increasing the Te coverage to 0.25 monolayer,the Au(100)-(1×1)surface becomes reduced and overlapped by a well-ordered(2×2)-Te superstructure.No similar behavior is found for Te-decorated Au(111),Cu(111),Cu(100)surfaces,nor for the decorated Au(100)with other elements.This result may pave the way to design Au-based catalysts and,as an intermediate step,even potentially open a new route to constructing complex transition metal dichalcogenides.展开更多
Antibiotics and their metabolic byproducts are found in wastewater and natural water as a result of increased consumption,posing a major threat to humans and other living organisms.One of the most promising methods fo...Antibiotics and their metabolic byproducts are found in wastewater and natural water as a result of increased consumption,posing a major threat to humans and other living organisms.One of the most promising methods for their removal is adsorption using biochar because it offers excellent adsorption potential and is both affordable and environmentally beneficial.However,raw biochar frequently has a low adsorption capacity due to its limited pore structure and unfavorable surface characteristics.Biochar surface modifications using modifiers such as H3PO4,KOH,and NaOH have improved the surface area and thereby the adsorption capacity.Experimental methods for assessing the effectiveness and adsorption mechanism of modified biochar are costly and time-consuming.Density functional theory(DFT)was used to investigate the interfacial interactions and adsorption mechanism of tetracycline(TC),a widely used antibiotic for personal care and veterinary medication,on unmodified and modified biochar.The DFT calculations showed that the adsorption energy of TC on unmodified and modified biochar is in the following order:KOH-modified biochar(−2.38 eV)<NaOH-modified biochar(−2.20 eV)<unmodified biochar(−1.56 eV)<H3PO4-modified biochar(5.48 eV).The lower adsorption energy is associated with a stronger and more stable interaction between the adsorbent and the contaminant.This suggests that the adsorption of TC on KOH-modified biochar is more prolific and stable compared to the other biochar.This study provides an understanding of the mechanism underlying the adsorption of TC by modified biochar and can be used as a guide to screen for biochar with promising adsorption potential prior to experimental efforts.展开更多
Water electrolysis for energy-efficient H_(2)production coupled with hydrazine oxidation reaction(HzOR)is prevailing,while the sluggish electrocatalysts are strongly hindering its scalable application.Herein,we scheme...Water electrolysis for energy-efficient H_(2)production coupled with hydrazine oxidation reaction(HzOR)is prevailing,while the sluggish electrocatalysts are strongly hindering its scalable application.Herein,we schemed a novel porous Ce-doped Ni3N nanosheet arrays grown on nickel foam(Ce-Ni3N/NF)as a remarkable bifunctional catalyst for both hydrogen evolution reaction and HzOR.Significantly,the overall hydrazine splitting system can achieve low cell voltages of 0.156 and 0.671 V at 10 and 400 mA·cm^(−2),and the system is remarkably stable to operate over 100 h continuous test at the high-current-density of 400 mA·cm^(−2).Various characterizations prove that the porous nanosheet arrays expose more active sites,and more excellent diffusion kinetics and lower charge-transfer resistance,therefore boosting catalytic performance.Furthermore,density functional theory calculation reveals that the incorporation of Ce can effectively optimize the free energy of hydrogen adsorption and promote intrinsic catalytic activity of Ni_(3)N.展开更多
Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study...Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study,single-atom Ag was successfully anchored on ultrathin carbon nitride(UTCN)via thermal polymerization,the catalyst obtained is called AgUTCN.The Ag hardly changed the carbon nitride's layered and porous physical structure.AgUTCN exhibited efficient visible-light photocatalytic performances in the degradation of various recalcitrant pollutants,eliminations of 85% were achieved by visible-light irradiation for 1hr.Doping with Ag improved the photocatalytic performance of UTCN by narrowing the forbidden band gap from 2.49 to 2.36 e V and suppressing electron-hole pair recombination.In addition,Ag doping facilitated O_(2) adsorption on UTCN by decreasing the adsorption energy from -0.2 to -2.22 e V and favored the formation of O_(2)^(·-).Electron spin resonance and radical-quenching experiments showed that O_(2)^(·-)was the major reactive species in the degradation of Acetaminophen(paracetamol,APAP).展开更多
The adsorption of carbon atom on Fe surface and in Fe subsurface with and without rare earth(La and Ce)substitution in the surface layer and subsurface layer was studied by first-principles calculations.The carbon ato...The adsorption of carbon atom on Fe surface and in Fe subsurface with and without rare earth(La and Ce)substitution in the surface layer and subsurface layer was studied by first-principles calculations.The carbon atom is predicted to adsorb at hollow and long bridge site on Fe(100)and Fe(110),respectively.However,the carbon atom shifts to occupy preferentially hollow site on both Fe(100)and Fe(110)with rare earth atom doping at surface layer.The lower adsorption energies involved with stronger adsorption abilities were obtained for carbon atoms on Fe surface with rare earth doping at surface layer,which was determined by the electronic structure of the surface atoms.The La atom was pulled out the surface after carbon adsorption due to strong interaction of La-C,which is consistent with the more charge transfer.In the subsurface region,the carbon atom prefers to occupy at octahedral site with rare earth doping at surface layer in Fe slab.These strong adsorption energies of the carbon atoms on Fe surface and in Fe subsurface with rare earth pose relevant insights into the interaction between carbon and rare earth,which helps to understanding the influence mechanism of rare earth in carburizing.展开更多
Wax deposition in pipelines leads to pressure drop,reduced effective cross-sectional area,and blockages.Although mathematical models and experimental loops were used to model wax precipitation on pipeline surfaces,its...Wax deposition in pipelines leads to pressure drop,reduced effective cross-sectional area,and blockages.Although mathematical models and experimental loops were used to model wax precipitation on pipeline surfaces,its prediction at molecular levels is not fully recognized.Molecular dynamics is another powerful approach that can predict wax precipitation at the molecular level.This paper uses molecular dynamics simulations with the adsorption locator model found in Material Studio Software to investigate the adsorption behaviors of Icosane-C20H42,Docosane-C22H46,and Tetracosane-C24H50 paraffin waxes on the Fe,FeO,and Fe2O3 pipeline internal surfaces.Modeling is performed by varying temperature values and validated with experimental data.It was found that as the temperature altered,the adsorption energies,probability energy distribution and adsorption density field on the surfaces also changed;on the other hand,the energetic analysis results showed adsorption energies increase with carbon numbers increase due to its larger surface contacting areas and lower aspect ratio,which resulted in stronger interaction with the surfaces.Further,paraffin waxes showed to adsorb easily on Fe surfaces than oxide surfaces.At temperatures below Wax Appearance Temperature(WAT)on both simulations and experiments showed wax deposition.The lower adsorption energy capacity observed on the Fe2O3 pipeline surface confirms it's vitality and suitability for crude oil transportation pipelines surface lining material.展开更多
Electrocatalytic nitrate reduction to ammonia(NRA)under ambient conditions is significant for carbonneutral synthetic fuels.Nevertheless,the lack of efficient electrocatalysts with tunable nanostructure for NRA remain...Electrocatalytic nitrate reduction to ammonia(NRA)under ambient conditions is significant for carbonneutral synthetic fuels.Nevertheless,the lack of efficient electrocatalysts with tunable nanostructure for NRA remains a grand challenge.Herein,Nb WO_(6)nanosheets with oxygen vacancy(NbWO_(6-x))was demonstrated via thermal treatment and exfoliation with NH_(3)selectivity of 86.8%and Faradaic efficiency of85.7%toward NRA.^(1)H nuclear magnetic resonance spectra coupled with^(15)N isotope labeling experiments proved that NH_(3)originated from NO_(3)^-.The function of oxygen vacancy was revealed by computational studies in NRA.Moreover,the reaction mechanism and pathway of NRA could be deduced based on the results of online differential electrochemical mass spectrometry(DEMS).This work provides a selective NH_(3)generation strategy to decarbonize the energy-chemical sector,bridging the gap between batteries and biofuels.展开更多
Nine organic compounds were utilized as model lubricants to investigate the impact of functional groups on tribological performances.Nonanoic Acid with carboxyl showed the best lubrication properties,and fluid film an...Nine organic compounds were utilized as model lubricants to investigate the impact of functional groups on tribological performances.Nonanoic Acid with carboxyl showed the best lubrication properties,and fluid film and tribofilm were coexistent in its friction test,bringing a low friction coefficient and wear rate.In addition,the lubricant with low friction coefficient corresponded to high adsorption energy in density functional theory(DFT)calculations.And the lubricant forming adsorption film with large surface energy displayed small wear rate in friction test.Moreover,adsorption energies positively correlated surface energies.Based on the experimental results,the action mechanism of functional groups on tribological properties of lubricants was proposed.Various functional groups make lubricant molecules show different adsorption energies and surface energies.Lubricant molecules with high adsorption energy are more likely to adsorb on substrates and form a vertical monolayer,which can maintain a regular molecular brush structure during friction and bring a low friction coefficient.And lubricant molecules with high surface energy may be more prone having tribochemical reactions during friction and forming protective tribofilm,which leads to a low wear rate.展开更多
Electrochemical nitrate reduction reaction(NO_(3)RR)has great potential for ammonia(NH_(3))synthesis benefiting from its environmental friendliness and sustainability.Cu-based alloys with elemental diversity and adsor...Electrochemical nitrate reduction reaction(NO_(3)RR)has great potential for ammonia(NH_(3))synthesis benefiting from its environmental friendliness and sustainability.Cu-based alloys with elemental diversity and adsorption tunability are widely used as electrocatalyst to lower the reaction overpotential for NO_(3)RR catalysis.However,phase separation commonly found in alloys leads to uneven distribution of elements,which limits the possibility of further optimizing the catalytic activity.Herein,an electrotriggered Joule heating method,possessing unique superiority of flash heating and cooling that lead to well-dispersed nanoparticles and uniform mixing of various elements,was adopted to synthesize a single-phase CuNi nano-alloy catalyst evenly dispersed on carbon fiber paper,CFP-Cu_(1)Ni_(1),which exhibited a more positive NO_(3)RR initial potential of 0.1 V versus reversible hydrogen electrode(vs.RHE)than that of pure copper nanoparticles at 10 mA·cm^(−2)in 0.5 mol·L^(−1)Na_(2)SO_(4)+0.1 mol·L^(−1)KNO_(3)solution.Importantly,CFP-Cu_(1)Ni_(1) presented high electrocatalytic activity with a Faradaic efficiency of 95.7%and NH_(3)yield rate of 180.58μmol·h^(−1)·cm^(−2)(2550μmol·h^(−1)·mg_(cat)^(−1))at−0.22 V vs.RHE.Theoretical calculations showed that alloying Cu with Ni into single-phase caused an upshift of its d-band center,which promoted the adsorption of NO_(3)−and weakened the adsorption of NH_(3).Moreover,the competitive adsorption of hydrogen ions was restrained until−0.24 V.This work offers a rational design concept with clear guidance for rapid synthesis of uniformly dispersed single-phase nano-alloy catalyst for efficient electrochemical NO_(3)RR toward ammonia.展开更多
Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-ind...Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.展开更多
基金supported by Key Science and Technology Innovation Team of Shaanxi Province(No.2022TD-33)National Natural Science Foundation of China(Grant Nos.21373161,21504067)。
文摘Traditional selection of combustion catalysis is time-consuming and labor-intensive.Theoretical calculation is expected to resolve this problem.The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3,since HMX and O are key substances in decomposition process.And the relationship between the adsorption energy of HMX,O on metal oxides(TiO_(2),Al_(2)O_(3),PbO,CuO,Fe_(2)O_(3),Co_(3)O_(4),Bi_(2)O_(3),NiO)and experimental T30 values(time required for the decomposition depth of HMX to reach 30%)was depicted as volcano plot.Thus,the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data.Further,the adsorption energy of HMX on ZrO_(2)and MnO_(2)was predicted based on the linear relationship between surface energy and adsorption energy,and T30 values were estimated based on volcano plot.The apparent activation energy data of HMX/MgO,HMX/SnO_(2),HMX/ZrO_(2),and HMX/MnO_(2)obtained from DSC experiments are basically consistent with our predicted T30 values,indicating that it is feasible to predict the catalytic activity based on the adsorption calculation,and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost.
基金This work was supported by the National Natural Science Foundation of China(No.52002122)the Science and Technology Department of Hubei Province(No.2019AAA038)+1 种基金the Project funded by China Postdoctoral Science Foundation(No.2021M690947)the Wuhan Yellow Crane Talent Program(No.2017-02).
文摘The alkaline zinc-based batteries with high energy density are becoming a research hotspot.However,the poor cycle stability and low-rate performance limit their wide application.Herein,ultra-thin CoNiO2 nanosheet with rich oxygen defects anchored on the vertically arranged Ni nanotube arrays(Od-CNO@Ni NTs)is used as a positive material for rechargeable alkaline Ni–Zn batteries.As the highly uniform Ni nanotube arrays provide a fast electron/ion transport path and abundant active sites,the Od-CNO@Ni NTs electrode delivers excellent capacity(432.7 mAh g^(−1))and rate capability(218.3 mAh g^(−1) at 60 A g^(−1)).Moreover,our Od-CNO@Ni NTs//Zn battery is capable of an ultra-long lifespan(93.0%of initial capacity after 5000 cycles),extremely high energy density of 547.5 Wh kg^(−1) and power density of 92.9 kW kg^(−1)(based on the mass of cathode active substance).Meanwhile,the theoretical calculations reveal that the oxygen defects can enhance the interaction between electrode surface and electrolyte ions,contributing to higher capacity.This work opens a reasonable idea for the development of ultra-durable,ultra-fast,and high-energy Ni–Zn battery.
基金supported by the National Natural Science Foundation of China(21573059 and U1704251)the Overseas Expertise Introduction Project for Discipline Innovation(D17007)the Natural Science Foundation of Henan Province(212300410178)。
文摘The great challenges are remained in constructing graphite-based anode with well built-in structures to accelerate kinetics and enhance stability in the advanced K-ion batteries(KIBs).Here,we firstly report the design of expanded graphite cohered by N,B bridge-doping carbon patches(NBEG)for efficient K-ion adsorption/diffusion and long-term durability.It is the B co-doping that plays a crucial role in maximizing doping-site utilization of N atoms,balancing the adsorption-diffusion kinetics,and promoting the charge transfer between NBEG and K ions.Especially,the robust lamellar structure,suitable interlayer distance,and rich active sites of the designed NBEG favor the rapid ion/electron transfer pathways and high K-ion storage capacity.Consequently,even at a low N,B doping concentration(4.36 at%,2.07 at%),NBEG anode shows prominent electrochemical performance for KIBs,surpassing most of the advanced carbon-based anodes.Kinetic studies,density functional theory simulations,and in-situ Raman spectroscopy are further performed to reveal the K-ion storage mechanism and confirm the critical actions of co-doping B.This work offers the new methods for graphite-electrode design and the deeper insights into their energy storage mechanisms in KIBs.
基金Funded by the Academician Workstation of Yi Chang Hui Long Science and Technology Co.Ltd. Association of Science and Technology of Hubei Province[2013]104-22
文摘We discussed the oxidation differential and mechanisms on different planes of pyrite. The experimental results show that the oxidation priority is:(222) plane>(200) plane>(200) plane, and there is no direct correlation between the crystal plane index, the atom numbers, and the oxidation priority. However, with more exchanged charge among atoms, the oxidation could be conducted more easily, and the distribution rule of the electric charge conforms with the variation trend of adsorption energy, which will provide more overall cognition on the oxidation mechanism of pyrite from the atomic scale.
文摘First principles calculation is performed to study the co-adsorption behaviors of O_(2)and CO_(2)onδ-Pu(100)surface by using a slab model within the framework of density functional theory(DFT).The results demonstrate that the most favorable co-adsorption configurations are T_(v)-C_(4)O_(7)and T_(p1)-C_(2)O_(8),with adsorption energy of-17.296 e V and-23.131 e V for CO_(2)-based and O_(2)-based system,respectively.The C and O atoms mainly interact with the Pu surface atoms.Furthermore,the chemical bonding between C/O and Pu atom is mainly of ionic state,and the reaction mechanism is that C 2 s,C 2 p,O 2s,and O 2p orbitals overlap and hybridize with Pu 6 p,Pu 6 d,and Pu 5 f orbital,resulting in the occurrence of new band structure.The adsorption and dissociation of CO_(2)molecule are obviously promoted by preferentially occupying adsorbed O atoms,therefore,a potential CO_(2)protection mechanism for plutonium-based materials is that in CO_(2)molecule there occurs complete dissociation of CO_(2)→C+O+O,then the dissociated C atom combines with O atom from O_(2)dissociation and produces CO,which will inhibit the O_(2)from further oxidizing Pu surface,and slow down the corrosion rate of plutoniumbased materials.
基金financial support from the Science Foundation for Outstanding Young Scholars of Shandong Province (No. 2022HWYQ- 009)the Natural Science Foundation of Shandong Province (No. ZR2021QB201, No. YDZX2021001)the Qilu Young Scholars Program of Shandong University。
文摘Although a few pristine metal-organic frameworks(MOFs) of graphene analogue topology exhibit high intrinsic electrical conductivity, their use in lithium-ion batteries(LIBs) is still hampered by unfavorable Li+adsorption energy(ΔEa). In this paper, an electroconductive ferrocene-based MOF@MXene heterostructure is built to provide stable anodes for Li+storage. Charge density difference and planar average potential charge density show substantial redistribution of charges at the interfaces, transferring from MXene to MOF layers. Moreover, density functional theory(DFT) calculations reveal that the interaction between MXene and MOF significantly increases the ΔEa. As a result, the heterostructure anode exhibits high capacities and outstanding cycling stability with a capacity retention of 80% after 5000 cycles at 5 A g^(-1), outperforming mono-component MXene and MOF. Furthermore, the heterostructure anode is built into a full cell with a commercial NCM 532 cathode, delivering a high energy density of 611 Wh kg^(-1)and power density of 7600 W kg^(-1). The developed conductive MOF@MXene heterogeneity for improved LIB offers valuable insights into the design of advanced electrode materials for energy storage.
基金financially supported by the National Natural Science Foundation of China(Grant No.21905033)the Science and Technology Department of Sichuan Province(Grant No.2019YJ0503)the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(2020P4FZG02A)。
文摘Uncontrollable Li dendrite growth and infinite volume fluctuation during durative plating and stripping process gravely hinder the application of metallic Li electrode in lithium-oxygen batteries.Herein,oxygen vacancy-rich TiO_(2)(Vo-TiO_(2))nanoparticles(NPs)uniformly dispersing on Ti_(3)C_(2)T_(x)(Vo-TiO_(2)/Ti_(3)C_(2) T_(x))with excellent lithiophilicity feature are presented as effective composite anodes,on which a dense and uniform Li growth behavior is observed.Based on electrochemical studies,mutiphysics simulation and theoretical calculation,it is found that Vo-TiO_(2) coupling with three dimensional(3 D)conductive Ti_(3)C_(2) T_(x) MXene forms highly ordered lithiophilic sites which succeed in guiding Li ions flux and adsorption,thus modulating the uniform Li nucleation and growth.As a result,this composite electrode is capable of preserving Li with high areal capacity of~10 mAh cm^(-2) without the presence of dendrites and large volume expansion.Consequently,the as-prepared Vo-TiO_(2)/Ti_(3)C_(2) T_(x)@Li anode shows outstanding performance including low voltage hysteresis(~19 mV)and superior durability(over 750 h).When assembling with the Vo-TiO_(2)/Ti_(3)C_(2) T_(x)@Li anodes,lithium-oxygen batteries also deliver enhanced cycling stability and improved rate performance.This work demonstrates the effectiveness of oxygen vacancies in guiding Li nucleating and plating behavior at initial stage and brings a promising strategy for promoting the development of advanced Li metal-based batteries.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974253 and 11774248)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2017YFA0303600)
文摘Beryllium carbide is used in inertial confinement fusion(ICF)capsule ablation material due to its low atomic number,low opacity,and high melting point properties.We used the method of climbing image nudged elastic band(CINEB)to calculate the diffusion barrier of copper atom in the crystal of beryllium and beryllium carbide.The diffusion barrier of copper atom in crystal beryllium is only 0.79 eV,and the barrier in beryllium carbide is larger than 2.85 eV.The three structures of beryllium carbide:anti-fluorite Be2C,Be2C-Ⅰ,and Be2C-Ⅲhave a good blocking effect to the diffusion of copper atom.Among them,the Be2C-Ⅲstructure has the highest diffusion barrier of 6.09 eV.Our research can provide useful help for studying Cu diffusion barrier materials.
文摘With the increase of hard disk storage density,the flying height of magnetic head sliders has become lower in recent years,which makes it easier for lubricant materials to transfer between the magnetic head and disk.The ability for lubricant materials to transfer is not only related to the operating conditions of disk but also related to the types of lubricant materials(Perfluoropolyether,PFPE)and diamond⁃like carbon(DLC)coating applied to the disk.Based on the principle of molecular dynamics,this study established the adsorption models on disks with different carbon content and the diffusion models of several common PFPE molecules in air.Besides,the adsorption energy and the diffusion coefficients of different models were calculated.Furthermore,the molecular weight,the molecular structure,the lubricant materials end functional groups,and the disks carbon content were found to have influence on the transfer ability of lubricant materials.In particular,the latter two factors have further influence.
基金This work was financially supported by the National Natural Science Foundation of China(No.51603092)“High level talent steed plan”of Inner Mongolia University,and the China Postdoctoral Science Foundation(No.2019T120393).
文摘Herein,we prepare the unique hierarchical polypyrrole@cobalt sulfide(PPy-hs@CoS)hollow sphere-based nanofilms as interdigitated electrodes for flexible on-chip micro-supercapacitors(MSC).Benefiting from the excellent flexibility and high electrical conductivity of PPy-hs combined with the great electrochemical activity of CoS,such PPy-hs@CoS composite material can not only inhibit the volume expansion of PPy but also promote the diffusion of the electrolyte ions.The PPy-hs@CoS filmbased electrode delivers a greatly improved specific capacitance and small resistance.Density functional theory calculations infer that OH−prefers to bind to PPy on CoS@PPy and confirms the synergistic effect of each component for enhanced reaction kinetics.A quasi-solid-state on-chip flexible asymmetric MSC based on PPy-hs@CoS and activated carbon(AC)microelectrodes exhibits large areal-specific capacitance(131.9 mF/cm2 at 0.3 mA/cm2),ultrahigh energy density(0.041 mWh/cm2@0.224 mW/cm2 and 25.6 mWh/cm3@140.6 mW/cm3),and long cycle lifespan.We demonstrate the possibility to scale up the PPy-hs@CoS nanofilm microelectrode by arranging two of our asymmetric MSC in series and parallel connections,which respectively increase the output voltage and current.A self-charging system by connecting our asymmetric MSCs with a piece of commercial solar cells is developed as a potential possible mode for future highly durable and high-voltage integrated electronics.
基金the National Natural Science Foundation of China(No.1210040808)the Natural Science Foundation of Jiangsu Province(Nos.BK20210312 and BK20212008)+3 种基金the National Key Research and Development Program of China(No.2019YFA0705400)the Fundamental Research Funds for the Central Universities(Nos.NJ2022002,NZ2020001,and NS2022014)the Program for Innovative Talents and Entrepreneur in Jiangsu,Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Nos.MCMS-I-0419G02 and MCMS-I-0421K01)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘The Au(100)surface has been a subject of intense studies due to excellent catalytic activities and its model character for surface science.However,the spontaneous surface reconstruction buries active Au(100)plane and limits practical applications,how to controllably eliminate the surface reconstruction over large scale remains challenging.Here,we experimentally and theoretically demonstrate that simple decoration of the Au(100)surface by tellurium(Te)atoms can uniquely lift its reconstruction over large scale.Scanning tunneling microscopy imaging reveals that the lifting of surface reconstruction preferentially starts from the boundaries of distinct domains and then extends progressively into the domains with the reconstruction rows perpendicular to the boundaries,leaving a Au(100)-(1×1)surface behind.The Au(100)-(1×1)is saturated at~84%±2%with respect to the whole surface at a Te coverage of 0.16 monolayer.With further increasing the Te coverage to 0.25 monolayer,the Au(100)-(1×1)surface becomes reduced and overlapped by a well-ordered(2×2)-Te superstructure.No similar behavior is found for Te-decorated Au(111),Cu(111),Cu(100)surfaces,nor for the decorated Au(100)with other elements.This result may pave the way to design Au-based catalysts and,as an intermediate step,even potentially open a new route to constructing complex transition metal dichalcogenides.
文摘Antibiotics and their metabolic byproducts are found in wastewater and natural water as a result of increased consumption,posing a major threat to humans and other living organisms.One of the most promising methods for their removal is adsorption using biochar because it offers excellent adsorption potential and is both affordable and environmentally beneficial.However,raw biochar frequently has a low adsorption capacity due to its limited pore structure and unfavorable surface characteristics.Biochar surface modifications using modifiers such as H3PO4,KOH,and NaOH have improved the surface area and thereby the adsorption capacity.Experimental methods for assessing the effectiveness and adsorption mechanism of modified biochar are costly and time-consuming.Density functional theory(DFT)was used to investigate the interfacial interactions and adsorption mechanism of tetracycline(TC),a widely used antibiotic for personal care and veterinary medication,on unmodified and modified biochar.The DFT calculations showed that the adsorption energy of TC on unmodified and modified biochar is in the following order:KOH-modified biochar(−2.38 eV)<NaOH-modified biochar(−2.20 eV)<unmodified biochar(−1.56 eV)<H3PO4-modified biochar(5.48 eV).The lower adsorption energy is associated with a stronger and more stable interaction between the adsorbent and the contaminant.This suggests that the adsorption of TC on KOH-modified biochar is more prolific and stable compared to the other biochar.This study provides an understanding of the mechanism underlying the adsorption of TC by modified biochar and can be used as a guide to screen for biochar with promising adsorption potential prior to experimental efforts.
基金supported by Nantong University Analysis&Testing Center。
文摘Water electrolysis for energy-efficient H_(2)production coupled with hydrazine oxidation reaction(HzOR)is prevailing,while the sluggish electrocatalysts are strongly hindering its scalable application.Herein,we schemed a novel porous Ce-doped Ni3N nanosheet arrays grown on nickel foam(Ce-Ni3N/NF)as a remarkable bifunctional catalyst for both hydrogen evolution reaction and HzOR.Significantly,the overall hydrazine splitting system can achieve low cell voltages of 0.156 and 0.671 V at 10 and 400 mA·cm^(−2),and the system is remarkably stable to operate over 100 h continuous test at the high-current-density of 400 mA·cm^(−2).Various characterizations prove that the porous nanosheet arrays expose more active sites,and more excellent diffusion kinetics and lower charge-transfer resistance,therefore boosting catalytic performance.Furthermore,density functional theory calculation reveals that the incorporation of Ce can effectively optimize the free energy of hydrogen adsorption and promote intrinsic catalytic activity of Ni_(3)N.
基金supported by the Shenzhen Science,Technology and Innovation Commission(No.JCYJ20200109142829123)the National Natural Science Foundation of China(No.52022049)。
文摘Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study,single-atom Ag was successfully anchored on ultrathin carbon nitride(UTCN)via thermal polymerization,the catalyst obtained is called AgUTCN.The Ag hardly changed the carbon nitride's layered and porous physical structure.AgUTCN exhibited efficient visible-light photocatalytic performances in the degradation of various recalcitrant pollutants,eliminations of 85% were achieved by visible-light irradiation for 1hr.Doping with Ag improved the photocatalytic performance of UTCN by narrowing the forbidden band gap from 2.49 to 2.36 e V and suppressing electron-hole pair recombination.In addition,Ag doping facilitated O_(2) adsorption on UTCN by decreasing the adsorption energy from -0.2 to -2.22 e V and favored the formation of O_(2)^(·-).Electron spin resonance and radical-quenching experiments showed that O_(2)^(·-)was the major reactive species in the degradation of Acetaminophen(paracetamol,APAP).
基金Project supported by the Anhui Provincial Key Research and Development Program(202004h07020020,202004b11020011)National Natural Science Foundation of China(21771182)。
文摘The adsorption of carbon atom on Fe surface and in Fe subsurface with and without rare earth(La and Ce)substitution in the surface layer and subsurface layer was studied by first-principles calculations.The carbon atom is predicted to adsorb at hollow and long bridge site on Fe(100)and Fe(110),respectively.However,the carbon atom shifts to occupy preferentially hollow site on both Fe(100)and Fe(110)with rare earth atom doping at surface layer.The lower adsorption energies involved with stronger adsorption abilities were obtained for carbon atoms on Fe surface with rare earth doping at surface layer,which was determined by the electronic structure of the surface atoms.The La atom was pulled out the surface after carbon adsorption due to strong interaction of La-C,which is consistent with the more charge transfer.In the subsurface region,the carbon atom prefers to occupy at octahedral site with rare earth doping at surface layer in Fe slab.These strong adsorption energies of the carbon atoms on Fe surface and in Fe subsurface with rare earth pose relevant insights into the interaction between carbon and rare earth,which helps to understanding the influence mechanism of rare earth in carburizing.
基金This study was funded by China National Natural Science Foundation[Grant number 51704319 and 51574274].
文摘Wax deposition in pipelines leads to pressure drop,reduced effective cross-sectional area,and blockages.Although mathematical models and experimental loops were used to model wax precipitation on pipeline surfaces,its prediction at molecular levels is not fully recognized.Molecular dynamics is another powerful approach that can predict wax precipitation at the molecular level.This paper uses molecular dynamics simulations with the adsorption locator model found in Material Studio Software to investigate the adsorption behaviors of Icosane-C20H42,Docosane-C22H46,and Tetracosane-C24H50 paraffin waxes on the Fe,FeO,and Fe2O3 pipeline internal surfaces.Modeling is performed by varying temperature values and validated with experimental data.It was found that as the temperature altered,the adsorption energies,probability energy distribution and adsorption density field on the surfaces also changed;on the other hand,the energetic analysis results showed adsorption energies increase with carbon numbers increase due to its larger surface contacting areas and lower aspect ratio,which resulted in stronger interaction with the surfaces.Further,paraffin waxes showed to adsorb easily on Fe surfaces than oxide surfaces.At temperatures below Wax Appearance Temperature(WAT)on both simulations and experiments showed wax deposition.The lower adsorption energy capacity observed on the Fe2O3 pipeline surface confirms it's vitality and suitability for crude oil transportation pipelines surface lining material.
基金the supports from the National Natural Science Foundation of China(NSFC,Nos.22074104 and 51978491)National Program for Support of Top-notch Young Professionals+3 种基金the Fundamental Research Funds for the Central Universities(No.2022-4-ZD-07)“Shuguang Scholar Program”(No.17SG52)by Shanghai Education Development FoundationShanghai Municipal Education Commission,Liaoning Provincial Natural Science Fund Project(No.2019-ZD-0550)Scientific Research Foundation of Shanghai Institute of Technology(No.YJ2021-24)。
文摘Electrocatalytic nitrate reduction to ammonia(NRA)under ambient conditions is significant for carbonneutral synthetic fuels.Nevertheless,the lack of efficient electrocatalysts with tunable nanostructure for NRA remains a grand challenge.Herein,Nb WO_(6)nanosheets with oxygen vacancy(NbWO_(6-x))was demonstrated via thermal treatment and exfoliation with NH_(3)selectivity of 86.8%and Faradaic efficiency of85.7%toward NRA.^(1)H nuclear magnetic resonance spectra coupled with^(15)N isotope labeling experiments proved that NH_(3)originated from NO_(3)^-.The function of oxygen vacancy was revealed by computational studies in NRA.Moreover,the reaction mechanism and pathway of NRA could be deduced based on the results of online differential electrochemical mass spectrometry(DEMS).This work provides a selective NH_(3)generation strategy to decarbonize the energy-chemical sector,bridging the gap between batteries and biofuels.
基金grateful for the financial support from Youth Innovation Promotion Association,Chinese Academy of Sciences(2021422)Lanzhou Institute of Chemical Physics(LICP)Cooperation Foundation for Young Scholars(HZJJ20-06).
文摘Nine organic compounds were utilized as model lubricants to investigate the impact of functional groups on tribological performances.Nonanoic Acid with carboxyl showed the best lubrication properties,and fluid film and tribofilm were coexistent in its friction test,bringing a low friction coefficient and wear rate.In addition,the lubricant with low friction coefficient corresponded to high adsorption energy in density functional theory(DFT)calculations.And the lubricant forming adsorption film with large surface energy displayed small wear rate in friction test.Moreover,adsorption energies positively correlated surface energies.Based on the experimental results,the action mechanism of functional groups on tribological properties of lubricants was proposed.Various functional groups make lubricant molecules show different adsorption energies and surface energies.Lubricant molecules with high adsorption energy are more likely to adsorb on substrates and form a vertical monolayer,which can maintain a regular molecular brush structure during friction and bring a low friction coefficient.And lubricant molecules with high surface energy may be more prone having tribochemical reactions during friction and forming protective tribofilm,which leads to a low wear rate.
基金the National Natural Science Foundation of China(Nos.U1804255 and U22A20253)the Key Research&Development and Promotion Projects in Henan Province(Nos.222102520038 and 212102310060)。
文摘Electrochemical nitrate reduction reaction(NO_(3)RR)has great potential for ammonia(NH_(3))synthesis benefiting from its environmental friendliness and sustainability.Cu-based alloys with elemental diversity and adsorption tunability are widely used as electrocatalyst to lower the reaction overpotential for NO_(3)RR catalysis.However,phase separation commonly found in alloys leads to uneven distribution of elements,which limits the possibility of further optimizing the catalytic activity.Herein,an electrotriggered Joule heating method,possessing unique superiority of flash heating and cooling that lead to well-dispersed nanoparticles and uniform mixing of various elements,was adopted to synthesize a single-phase CuNi nano-alloy catalyst evenly dispersed on carbon fiber paper,CFP-Cu_(1)Ni_(1),which exhibited a more positive NO_(3)RR initial potential of 0.1 V versus reversible hydrogen electrode(vs.RHE)than that of pure copper nanoparticles at 10 mA·cm^(−2)in 0.5 mol·L^(−1)Na_(2)SO_(4)+0.1 mol·L^(−1)KNO_(3)solution.Importantly,CFP-Cu_(1)Ni_(1) presented high electrocatalytic activity with a Faradaic efficiency of 95.7%and NH_(3)yield rate of 180.58μmol·h^(−1)·cm^(−2)(2550μmol·h^(−1)·mg_(cat)^(−1))at−0.22 V vs.RHE.Theoretical calculations showed that alloying Cu with Ni into single-phase caused an upshift of its d-band center,which promoted the adsorption of NO_(3)−and weakened the adsorption of NH_(3).Moreover,the competitive adsorption of hydrogen ions was restrained until−0.24 V.This work offers a rational design concept with clear guidance for rapid synthesis of uniformly dispersed single-phase nano-alloy catalyst for efficient electrochemical NO_(3)RR toward ammonia.
基金This work was financially supported by the National Natural Science Foundation of China(No.22005097).
文摘Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.