Electronic structure regulation and built-in electric field synergistically strengthen photocatalytic nitrogen fixation performance on Ti-BiOBr/TiO_(2)heterostructure

At present,industrial synthetic ammonia was still obtained through the Hubble-Bosch process,with large energy consumption.It is a research hotspot to realize green synthetic ammonia by using solar energy.The difficulty of photocatalytic ammonia synthesis was that the photo-excited electrons have not enough energy to active N≡N.In this study,Ti was doped into BiOBr by one-step hydrothermal method,which was oxidized into TiO_(2)when the doping amount reaches the maximum,in situ forming Ti_(0.31)B_(0.69)OB/TiO_(2)composites.Benefiting from the synergistic effect of Ti doping and S-scheme heterojunction,the synthetic ammonia efficiency of Ti_(0.31)B_(0.69)OB/TiO_(2)-11.96 reached 1.643 mmol·g_(cat)^(-1)at mild conditions and without hole scavenger for up to 7 h,the efficiency of synthetic ammonia is 115 times,10.5 times and 3.3 times of that of BiOBr,Ti_(0.31)B_(0.69)OB and TiO_(2),respectively.Specifically,DFT calculation confirms that Ti doping accurately refine the electronic structure of BiOBr,facilitate nitrogen adsorption activation and reduce hydrogenation reaction energy barrier,thus accelerating the reaction kinetics of photocatalytic nitrogen reduction(NRR),Meanwhile,constructing S-scheme heterojunction boosts the separation and transfer of photogenerated electron-hole pairs,improving the reduction ability of electrons in the conduction band of TiO_(2)and the oxidation ability of holes in the valence band of Ti_(0.31)B_(0.69)OB.

Recent Progress and Regulation Strategies of Layered Materials as Cathode of Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries(ZIBs)have shown great potential in the fields of wearable devices,consumer electronics,and electric vehicles due to their high level of safety,low cost,and multiple electron transfer.The layered cathode materials of ZIBs hold a stable structure during charge and discharge reactions owing to the ultrafast and straightforward(de)intercalation-type storage mechanism of Zn^(2+)ions in their tunable interlayer spacing and their abilities to accommodate other guest ions or molecules.Nevertheless,the challenges of inadequate energy density,dissolution of active materials,uncontrollable byproducts,increased internal pressure,and a large de-solvation penalty have been deemed an obstacle to the development of ZIBs.In this review,recent strategies on the structure regulation of layered materials for aqueous zinc-ion energy storage devices are systematically summarized.Finally,critical science challenges and future outlooks are proposed to guide and promote the development of advanced cathode materials for ZIBs.

Structure regulation of land use and landscape pattern changes based on matter element analysis in a small watershed in Sichuan,China

The agricultural land suitability assessment based on the natural characteristics of land blocks is traditionally the basis for agricultural and/or land use planning.The assessment,however,is static and cannot be incorporated with potential land use changes.Recently,a dynamic approach,i.e.,matter element analysis,has been effectively applied for land use planning.In the present study,based on matter element analysis,we estab-lished a matter element analysis model for land use suitability assessment using the suitability grade of land use,evaluation indicators and their characteristic values as matter elements,and also using sutra field,controlled field,weight value and correlation degree from field survey,as well as an expert system.This model was applied to the structure regulation of the land use in the small Yuejiagou watershed of the Langzhong Municipality in Sichuan Province,China.Results show that the proportion among agriculture,forestry and animal husbandry tended to rationalize land use.The economic and eco-logical indices of the lands were increased from 1529.8 to 1719.99 and from 1460.94 to 1758.21 after the regulation,respectively.The regulation also caused changes in landscape patterns as follows:The indices of diversity and evenness were increased from 1.3028 to 2.0920 and from 0.6108 to 0.8463,or by 60.58%and 38.56%,respectively.However,the indices of dominance and contagion were decreased from 0.6431 to 0.2106 and from 0.7467 to 0.7125,respectively.This indicated that the land use in the small watershed was rational.The spatial distribution of patches tended to be uniform.The patch congregation was gradually dispersed.This study verified that the matter element analysis approach can not only overcome the factitious influences and improve the precision of land assessment,but also can be used for the structure regu-lation of specific patches.

Research progress of precise structural regulation of single atom catalyst for accelerating electrocatalytic oxygen reduction reaction

The development and utilization of renewable clean energy can effectively solve the two major problems of energy and environment. As an efficient power generation device that converts hydrogen energy into electric energy, fuel cell has attracted more and more attention. For fuel cells, the oxygen reduction reaction(ORR) at the cathode is the core reaction, and the design and development of high-performance ORR catalysts remain quite challenging. Since the microenvironment of the active center of single atom catalysts(SACs) has an important influence on its catalytic performance, it has been a research focus to improve the ORR activity and stability of electrocatalysts by adjusting the structure of the active center through reasonable structural regulation methods. In this review, we reviewed the preparation and structure–activity relationship of SACs for ORR. Then, the structural precision regulation methods for improving the activity and stability of ORR electrocatalysts are discussed. And the advanced in-situ characterization techniques for revealing the changes of active sites in the electrocatalytic ORR process are summarized. Finally, the challenges and future design directions of SACs for ORR are discussed. This work will provide important reference value for the design and synthesis of SACs with high activity and stability for ORR.

Atomically Dispersed Catalysts:Precise Synthesis,Structural Regulation,and Structure-Activity Relationship

Atomically dispersed catalysts(ADCs)have been diffusely researched for the development of advanced catalytic processes owing to their welldefined structure,high atomic utilization,and outstanding activity.Precisely decoding the intrinsic structures and coordination microenvironments of ADCs still confronts significant challenges.Overcoming these challenges is important for profound understanding of the structure-activity relationships and directing the future design of ADCs.Herein,this minireview summarizes recent progress and advanced characterization techniques for the engineering of ADCs,including single-atom catalysts,dualatom catalysts,and atomic cluster catalysts with regard to precise synthesis,structural regulation,and the structure-performance relationship.The catalytic merits and regulation strategies of recent breakthroughs in energy conversion,enzyme mimicry,and organic synthesis are thoroughly discussed to disclose the catalytic mechanism-guided ADCs design.Finally,a comprehensive summary of the future challenges and potential prospects is presented to stimulate more design and application possibilities for ADCs.We believe that this comprehensive minireview will open up novel pathways for the widespread utilization of ADCs in diverse catalytic processes.

Emerging two-dimensional metallenes:Recent advances in structural regulations and electrocatalytic applications

Benefiting from the ultrahigh specific surface areas,highly accessible surface atoms,and highly tunable microscopic structures,the two-dimensional metallenes as nanocatalysts have displayed promising performance for various electrocatalytic reactions.Herein,we reviewed recent advances on metallenes in structural regulations including defect,phase,strain,interface,doping,and alloying engineering strategies and their applications in energy electrocatalytic reactions involving oxygen reduction reaction,carbon dioxide reduction reaction,hydrogen evolution reaction,and small molecules oxidation reaction.Finally,we proposed the future challenges and directions in this emerging area.

Structural Fiscal Regulation and Choice of Instruments in the New Normal

Based on the overall consideration of individual behaviors of Ricardian and non-Ricardian households, this paper develops a New Keynesian dynamic stochastic general equilibrium(DSGE) model to form a relatively systematic research framework for analyzing the economic effects of structural fiscal instruments. Our study findsthat great differences exist in the macroeconomic effects of different fiscal instruments, suggesting that the government should prudently select these fiscal instruments in fiscal macro-control. The simulating results of fiscal shocks show that the effect of tax cut is superior to the effect of increased spending. In the context of slowing economic growth and less potent stimulation policy, the government should transform its previous regulatory approach of fiscal policy and shift from hefty spending stimulus policy to structural tax cuts. This paper believes that China should step up the implementation of public-private partnership, increase its spending on social security, healthcare, pension and public services and facilitate the transition toward a service-based government; and that tax policy should focus on structural tax cuts on consumption to promote the transition of demand structure toward consumption-driven.

Synthesis,Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-（3-amino-[1,2,4]triazol-1-yl）-3,3-dimethyl-butan-2-one（3） was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one（1） and ~1H-[1,2,4]triazol-3-ylamine（2） with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227（8）, b = 27.924（4）, c = 6.2282（7） ？, β = 101.892（11）°, V = 973.9（2） ？~3, Z = 4, T = 180.00（10） K, μ（MoKα） = 0.087 mm^（-1）, Dc = 1.243 g/cm^3, 3832 reflections measured（3.648≤θ≤26.022°）, 1916 unique reflections（Rint = 0.0359, Rsigma = 0.0572） used in all calculations. The final R = 0.0557（I 〉 2σ（I）） and w R = 0.1276（all data）. Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L（50 ppm） in soybeen（He Feng-50）. Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.

Charge-transfer-regulated bimetal ferrocene-based organic frameworks for promoting electrocatalytic oxygen evolution

The ferrocene(Fc)-based metal-organic frameworks(MOFs)are regarded as compelling platforms for the construction of efficient and robust oxygen evolution reaction(OER)electrocatalysts due to their superior conductivity and flexible electronic structure.Herein,density functional theory simulations were addressed to predict the electronic structure regulations of CoFc-MOF by nickel doping,which demonstrated that the well-proposed CoNiFc-MOFs delivered a small energy barrier,promoted conductivity,and well-regulated d-band center.Inspired by these,a series of sea-urchin-like CoNiFc-MOFs were successfully synthesized via a facile solvothermal method.Moreover,the synchrotron X-ray and X-ray photoelectron spectroscopy measurements manifested that the introduction of nickel could tailor the electronic structure of the catalyst and induce the directional transfer of electrons,thus optimizing the rate-determining step of^(*)O→^(*)OOH during the OER process and yielding decent overpotentials of 209 and 252 mV at 10 and 200 mA cm^(−2),respectively,with a small Tafel slope of 39 mV dec^(−1).This work presents a new paradigm for developing highly efficient and durable MOF-based electrocatalysts for OER.

In situ confined vertical growth of Co_(2.5)Ni_(0.5)Si_(2)O_(5)(OH)_(4)nanoarrays on rGO for an efficient oxygen evolution reaction

Rational design of oxygen evolution reaction(OER)catalysts at low cost would greatly benefit the economy.Taking advantage of earth-abundant elements Si,Co and Ni,we produce a unique-structure where cobalt-nickel silicate hydroxide[Co_(2.5)Ni_(0.5)Si_(2)O_(5)(OH)_(4)]is vertically grown on a reduced graphene oxide(rGO)support(CNS@rGO).This is developed as a low-cost and prospective OER catalyst.Compared to cobalt or nickel silicate hydroxide@rGO(CS@rGO and NS@rGO,respectively)nanoarrays,the bimetal CNS@rGO nanoarray exhibits impressive OER performance with an overpotential of 307 mV@10 mA cm^(-2).This value is higher than that of CS@rGO and NS@rGO.The CNS@rGO nanoarray has an overpotential of 446 mV@100 mA cm^(-2),about 1.4 times that of the commercial RuO_(2)electrocatalyst.The achieved OER activity is superior to the state-of-the-art metal oxides/hydroxides and their derivatives.The vertically grown nanostructure and optimized metal-support electronic interactions play an indispensable role for OER performance improvement,including a fast electron transfer pathway,short proton/electron diffusion distance,more active metal centers,as well as optimized dualatomic electron density.Taking advantage of interlay chemical regulation and the in-situ growth method,the advanced-structural CNS@rGO nanoarrays provide a new horizon to the rational and flexible design of efficient and promising OER electrocatalysts.

Single-cluster electronics using metallic clusters:Fabrications,regulations,and applications

Metallic clusters,ranging from 1 to 2 nm in size,have emerged as promising candidates for creating nanoelectronic devices at the single-cluster level.With the intermediate quantum properties between metals and semiconductors,these metallic clusters offer an alternative pathway to silicon-based electronics and organic molecules for miniaturized electronics with dimensions below 5 nm.Significant progress has been made in studies of single-cluster electronic devices.However,a clear guide for selecting,synthesizing,and fabricating functional single-cluster electronic devices is still required.This review article provides a comprehensive overview of single-cluster electronic devices,including the mechanisms of electron transport,the fabrication of devices,and the regulations of electron transport properties.Furthermore,we discuss the challenges and future directions for single-cluster electronic devices and their potential applications.

Electronic modulation of two-dimensional bismuth-based nanosheets for electrocatalytic CO_(2) reduction to formate: A review

Electrocatalytic CO_(2) reduction reaction(eCO_(2) RR)has significant relevance to settle the global energy crisis and abnormal climate problem via mitigating the excess emission of waste CO_(2) and producing high-value-added chemicals.Currently,eCO_(2) RR to formic acid or formate is one of the most technologically and economically viable approaches to realize high-efficiency CO_(2) utilization,and the development of efficient electrocatalysts is very urgent to achieve efficient and stable catalytic performance.In this review,the recent advances for two-dimensional bismuth-based nanosheets(2D Bi-based NSs)electrocatalysts are concluded from both theoretical and experimental perspectives.Firstly,the preparation strategies of 2D Bi-based NSs in aspects to precisely control the thickness and uniformity are summarized.In addition,the electronic regulation strategies of 2D Bi-based NSs are highlighted to gain insight into the effects of the structure-property relationship on facilitating CO_(2) activation,improving product selectivity,and optimizing carrier transport dynamics.Finally,the considerable challenges and opportunities of 2D Bi-based NSs are discussed to lighten new directions for future research of eCO_(2) RR.

Single-atom sites regulation by the second-shell doping for efficient electrochemical CO_(2)reduction

Nitrogen-doped carbon loaded single-atom catalysts(SACs)are promising candidates for electrocatalytic conversion of CO_(2)into high-valuable chemicals,and the modification of catalysts by heteroatom-doping strategy is an effective approach to enhance the CO_(2)reduction performance.However,the large difference exists in atomic radius between nitrogen atoms and the doped heteroatoms may lead to the poor stability of active sites.In this study,we have synthesized a Ni single atom catalyst with S doping at the secondshell on the ultrathin carbon nanosheets support(Ni-N_(4)-SC)by solid-phase pyrolysis.The S atom in the second-shell contributes to the higher efficiency of CO_(2)conversion at lower potentials while the Ni-N_(4)-SC can be more stable.The experimental results and theoretical calculations indicate that the S atom in second-shell breaks the uniform charge distribution and reduces the free energy of hydrogenation,which can increase the adsorption of CO_(2),accelerate charge transfer,and reduce the reaction energy barrier.This work reveals the close relationship between the second-shell and the electrocatalytic activity of single atom sites,which also provides a new perspective to design efficient single atom catalysts.

Structural Regulations of Layered Borates:From Centric Layers to Chiral Porous Layers

Three pentaborates were made by precise structural regulations under hydrothermal conditions,namely,K_(2)Cs-[B_(5)O_(8)(OH)]·0.5CO_(3)(1),KNa_(4)Cs[B_(5)O_(8)(OH)]_(2)·2OH(2),and NaBa[B_(5)O_(8.5)(OH)](3).Compound 1 features the typical 2D layers constructed from the four-connected B_(5)O_(10)(OH)clusters.By adjustment of the reactants and pH values of the systems to remove interlayered CO_(3)^(2−)groups,the centric layers in 1 were transformed to the chiral layers of 2.By further adjusting cationic templates based on host−guest charge matching,the B_(5)O_(10)(OH)cluster unit was transformed to B_(5)O_(11)(OH),which built the chiral porous layers of 3.The chiral compounds 2 and 3 exhibit moderate second harmonic generation(SHG)responses of 1.1 and 1.7 times that of KDP(KH_(2)PO_(4)).The structural regulations actualize the evolutions on both structural symmetries and dimensions.

The recent progress of pitch-based carbon anodes in sodium-ion batteries

Sodium-ion batteries(SIBs)have attracted significant attentions as promising alternatives to lithium-ion batteries for large-scale energy storage applications.Here carbon materials are considered as the most competitive anodes for SIBs based on their low-cost,abundant availability and excellent structural stability.Pitch,with high carbon content and low cost,is an ideal raw precursor to prepare carbon materials for large-scale applications.Nevertheless,the microstructures of pitch-based carbon are highly ordered with smaller interlayer distances,which are unfavorable for Na ion storage.Many efforts have been made to improve the sodium storage performance of pitch-based carbon materials.This review summarizes the recent progress about the application of pitch-based carbons for SIBs anodes in the context of carbon’s morphology and structure regulation strategies,including morphology adjustment,heteroatoms doping,fabricating heterostructures,and the increase of the degree of disorder.Besides,the advantages,present challenges,and possible solutions to current issues in pitch-based carbon anode are discussed,with the highlight of future research directions.This review will provide a deep insight into the development of low-cost and high-performance pitch-based carbon anode for SIBs.

Effects of anions on the structural regulation of Zn‑salen‑modified metal‑organic cage

By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variational Zn-salen ligands RZn and NADH(reduced nicotinamide adenine dinucleotide)mimic modified tridentate ligands with square-planar Pd ions.UV-Vis and luminescence spectra experiments reveal that different anions could selec-tively interact with different sites of Zn-salen modified metal-organic cages to achieve the structural regulation of cage compound,by using the differentiated host-guest electrostatic interactions of counter ions with metal-organic hosts.Compared to other anions,the presence of chloride ions caused the most significant fluorescence emission enhancement of Pd‑R(Zn),meanwhile,the UV-Vis absorption band attributed to the salen aromatic backbone showed an absorption decrease,and the metal-to-ligand induced peak displayed a blue shift effect.Circular dichro-ism and ^(1)H NMR spectra further demonstrate that the introduction of chloride anions is beneficial to keeping a more rigid scaffold.

Few‐layer carbon nitride photocatalysts for solar fuels and chemicals:Current status and prospects

Converting sunlight directly to fuels and chemicals is a great latent capacity for storing renewable energy.Due to the advantages of large surface area,short diffusion paths for electrons,and more exposed active sites,few‐layer carbon nitride(FLCN)materials present great potential for production of solar fuels and chemicals and set off a new wave of research in the last few years.Herein,the recent progress in synthesis and regulation of FLCN‐based photocatalysts,and their applications in the conversion of sunlight into fuels and chemicals,is summarized.More importantly,the regulation strategies from chemical modification to microstructure control toward the production of solar fuels and chemicals has been deeply analyzed,aiming to inspire critical thinking about the effective approaches for photocatalyst modification rather than developing new materials.At the end,the key scientific challenges and some future trend of FLCN‐based materials as advanced photocatalysts are also discussed.

Construction of N-doped carbon frames anchored with Co single atoms and Co nanoparticles as robust electrocatalyst for hydrogen evolution in the entire pH range

The development of low-cost, efficient, and high atomic economy electrocatalysts for hydrogen evolution reaction(HER) in the entire p H range for sustainable hydrogen production is of great importance but still challenging. Herein, we synthesize a highly dispersed N-doped carbon frames(NCFs) anchored with Co single atoms(SAs) and Co nanoparticles(NPs) catalyst by a doping-adsorption-pyrolysis strategy for electrocatalytic hydrogen evolution. The Co SAs-Co NPs/NCFs catalyst exhibits an excellent HER activity with small overpotential, low Tafel slope, high turnover frequency as well as remarkable stability. It also exhibits a superior HER performance in the entire p H range. Combining with experimental and theoretical calculation, we find that Co SAs with Co-N_(3) coordination structure and Co NPs have a strong interaction for promoting synergistic HER electrocatalytic process. The H_(2)O molecule is easily activated and dissociated on Co NPs, while the generated H^(*) is easily adsorbed on Co SAs for HER, which makes the Co SAs-Co NPs/NCFs catalyst exhibit more suitable H adsorption strength and more conducive to the activation and dissociation of H_(2)O molecules. This work not only proposes a novel idea for constructing coupling catalyst with atomic-level precision, but also provides strong reference for the development of high-efficiency HER electrocatalysts for practical application.

Modulate the electronic structure of Cu_(7)S_(4)nanosheet on TiO_(2)for enhanced photocatalytic hydrogen evolution

TiO_(2)is a promising photocatalyst due to its high thermodynamic stability and non-toxicity.However,its applications have been still limited because of the high recombination rate of electron-hole pairs.Herein,we show that by combining heterojunction construction and electronic structure regulation,the electron-hole pairs in TiO_(2)can be effectively separated for enhanced photocatalytic hydrogen evolution.The optimized Cu_(7)S_(4)nanosheet decorated TiO_(2)achieves much enhanced H_(2)evolution rate(11.5 mmol·g−1·h−1),which is 13.8 and 4.2 times of that of TiO_(2)and Cu_(7)S_(4)/TiO_(2),respectively.The results of photoluminescence spectroscopy,transient photocurrent spectra,ultraviolet-visible diffuse reflectance spectra,and electrochemical impedance spectroscopy collectively demonstrate that the enhanced photocatalytic performance of Air-Cu_(7)S_(4)/TiO_(2)is attributed to the effective separation of charge carriers and widened photoresponse range.The electron paramagnetic resonance and X-ray photoelectron spectroscopy results indicate that the increase of Cu2+in the Cu_(7)S_(4)nanosheet after calcination can promote the charge transfer.This work provides an effective method to improve the electron migration rate and charge separation of TiO_(2),which holds great significance for being extended to other material systems and beyond.

Regulating electronic structure of CoN_(4)with axial Co-S for promoting oxygen reduction and Zn-air battery performance

Regulating the coordination environment of transition-metal based materials in the axial direction with heteroatoms has shown great potential in boosting the oxygen reduction reaction(ORR).The coordination configuration and the regulation method are pivotal and elusive.Here,we report a combined strategy of matrix-activization and controlled-induction to modify the CoN_(4)site by axial coordination of Co-S(Co1N_(4)-S_(1)),which was validated by the aberration-corrected electron microscopy and X-ray absorption fine structure analysis.The optimal Co1N_(4)-S_(1)exhibits an excellent alkaline ORR activity,according to the half-wave potential(0.897 V vs.reversible hydrogen electrode(RHE)),Tafel slope(24.67 mV/dec),and kinetic current density.Moreover,the Co1N_(4)-S_(1)based Zn-air battery displays a high power density of 187.55 mW/cm^(2)and an outstanding charge-discharge cycling stability for 160 h,demonstrating the promising application potential.Theoretical calculations indicate that the better regulation of CoN_(4)on electronic structure and thus the highly efficient ORR performance can be achieved by axial Co-S.