石墨炔原子催化剂的崭新道路:基于自验证机器学习方法的筛选策略

近年来,原子催化剂(ACs)引起了广泛的研究关注.目前该领域的长足发展受限于贵金属的使用和单原子催化剂(SACs)的性能有限.本文总结了利用密度泛函理论(DFT)和机器学习(ML)方法筛选高效的基于石墨炔(GDY)的原子催化剂的工作.研究表明, Pd, Co, Pt和Hg可以形成稳定的零价过渡金属-石墨炔组合(TM-GDY),而镧系-过渡金属的双原子催化剂(Ln-TM DAC)组合通过f-d轨道耦合作用可以获得有效的催化性能提升.进一步分析表明,主族元素与过渡金属和镧系金属的结合可以通过p轨道耦合保持高电活性,从而构成高度稳定的GDY-DAC系统,机器学习算法也揭示了s,p轨道的作用.此外,理论算法技术在筛选催化水分解析氢反应(HER)的高效组合上也表现出了优越性,创新性地预测了石墨炔-原子催化剂在实际催化反应中的潜能.本综合评述可为未来设计新型原子催化剂提供新的思路与策略.

XAFS技术在单原子电催化中的应用

X射线吸收精细谱学(XAFS)技术是从20世纪80年代开始逐渐发展起来的一种材料表征技术,具有对中心吸收原子的局域结构和化学环境敏感的特征,非常适合表征单原子催化剂.本文从XAFS技术的原理和特点出发,深入探讨了该技术在电催化水分解、燃料电池阴极反应和二氧化碳电化学还原等多个单原子催化应用场景下的独特作用,并展望了XAFS技术在单原子电催化领域的未来发展与应用前景,以期为更深入明确的单原子催化剂结构表征和电催化机理描述提供指导.

Cu single-atom electrocatalyst on nitrogen-containing graphdiyne for CO_(2)electroreduction to CH4

Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2)reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N2-bidentate(note that N2-bidentate site=N^N-bidentate site;N2¹dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N2-bidentate site,a Cu SAC with isolated undercoordinated Cu-N2 sites(Cu1.0/N2-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N2-GDY exhibits the highest Faradaic efficiency(FE)of 80.6%for CH4 in electrocatalytic reduction of CO_(2)at-0.96 V vs.RHE,and the partial current density of CH4 is 160 mA cm^(-2).The selectivity for CH4 is maintained above 70%when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N2-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N2 sites are more favorable in generating key*COOH and*CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N2 sites toward efficient electrocatalysis.

Single-atom modified graphene cocatalyst for enhanced photocatalytic CO_(2)reduction on halide perovskite

Metal halide perovskite(MHP)has become one of the most promising materials for photocatalytic CO_(2)reduction owing to the wide light absorption range,negative conduction band position and high reduction ability.However,photoreduction of CO_(2)by MHP remains a challenge because of the slow charge separation and transfer.Herein,a cobalt single-atom modified nitrogen-doped graphene(Co-NG)cocatalyst is prepared for enhanced photocatalytic CO_(2)reduction of bismuth-based MHP Cs_(3)Bi_(2)Br_(9).The optimal Cs_(3)Bi_(2)Br_(9)/Co-NG composite exhibits the CO production rate of 123.16μmol g-1 h-1,which is 17.3 times higher than that of Cs_(3)Bi_(2)Br_(9).Moreover,the Cs_(3)Bi_(2)Br_(9)/Co-NG composite photocatalyst exhibits nearly 100%CO selectivity as well as impressive long-term stability.Charge carrier dynamic characterizations such as Kelvin probe force microscopy(KPFM),single-particle PL microscope and transient absorption(TA)spectroscopy demonstrate the vital role of Co-NG cocatalyst in accelerating the transfer and separation of photogenerated charges and improving photocatalytic performance.The reaction mechanism has been demonstrated by in situ diffuse reflectance infrared Fourier-transform spectroscopy measurement.In addition,in situ X-ray photoelectron spectroscopy test and theoretical calculation reveal the reaction reactive sites and reaction energy barriers,demonstrating that the introduction of Co-NG promotes the formation of~(*)COOH intermediate,providing sufficient evidence for the highly selective generation of CO.This work provides an effective single-atom-based cocatalyst modification strategy for photocatalytic CO_(2)reduction and is expected to shed light on other photocatalytic applications.

Poly(ethylenimine)-assisted synthesis of hollow carbon spheres comprising multi-sized Ni species for CO_(2)electroreduction

Electrochemical CO_(2)reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2)electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2)and a Faradaic efficiency of 93.0%at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2)reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.

Synergistic effect of heterogeneous single atoms and clusters for improved catalytic performance

Electrocatalytic water splitting provides an efficient method for the production of hydrogen.In electrocatalytic water splitting,the oxygen evolution reaction(OER)involves a kinetically sluggish four-electron transfer process,which limits the efficiency of electrocatalytic water splitting.Therefore,it is urgent to develop highly active OER catalysts to accelerate reaction kinetics.Coupling single atoms and clusters in one system is an innovative approach for developing efficient catalysts that can synergistically optimize the adsorption and configuration of intermediates and improve catalytic activity.However,research in this area is still scarce.Herein,we constructed a heterogeneous single-atom cluster system by anchoring Ir single atoms and Co clusters on the surface of Ni(OH)_(2)nanosheets.Ir single atoms and Co clusters synergistically improved the catalytic activity toward the OER.Specifically,Co_(n)Ir_(1)/Ni(OH)_(2)required an overpotential of 255 mV at a current density of 10 mA·cm^(−2),which was 60 mV and 67 mV lower than those of Co_(n)/Ni(OH)_(2)and Ir1/Ni(OH)_(2),respectively.The turnover frequency of Co_(n)Ir_(1)/Ni(OH)_(2)was 0.49 s^(−1),which was 4.9 times greater than that of Co_(n)/Ni(OH)_(2)at an overpotential of 300 mV.

Single-atom catalysts based on polarization switching of ferroelectric In_(2)Se_(3)for N2 reduction

The polarization switching plays a crucial role in controlling the final products in the catalytic pro-cess.The effect of polarization orientation on nitrogen reduction was investigated by anchoring transition metal atoms to form active centers on ferroelectric material In_(2)Se_(3).During the polariza-tion switching process,the difference in surface electrostatic potential leads to a redistribution of electronic states.This affects the interaction strength between the adsorbed small molecules and the catalyst substrate,thereby altering the reaction barrier.In addition,the surface states must be considered to prevent the adsorption of other small molecules(such as*O,*OH,and*H).Further-more,the V@↓-In_(2)Se_(3)possesses excellent catalytic properties,high electrochemical and thermody-namic stability,which facilitates the catalytic process.Machine learning also helps us further ex-plore the underlying mechanisms.The systematic investigation provides novel insights into the design and application of two-dimensional switchable ferroelectric catalysts for various chemical processes.

Fe-Mn/Al_2O_3 catalysts for low temperature selective catalytic reduction of NO with NH_3

A series of Fe‐Mn/Al2O3 catalysts were prepared and studied for low temperature selective catalytic reduction （SCR） of NO with NH3 in a fixed‐bed reactor. The effects of Fe and Mn on NO conversion and the deactivation of the catalysts were studied. N2 adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, H2 temperature‐programmed reduction, NH3 temperature‐programmed desorption, X‐ray photoelectron spectroscopy （XPS）, thermal gravimetric analysis and Fourier transform infrared spectroscopy were used to character‐ize the catalysts. The 8Fe‐8Mn/Al2O3 catalyst gave 99%of NO conversion at 150？？ and more than 92.6%NO conversion was obtained in a wide low temperature range of 90–210？？. XPS analysis demonstrated that the Fe3＋was the main iron valence state on the catalyst surface and the addition of Mn increased the accumulation of Fe on the surface. The higher specific surface area, enhanced dispersion of amorphous Fe and Mn, improved reduction properties and surface acidity, lower binding energy, higher Mn4＋/Mn3＋ratio and more adsorbed oxygen species resulted in higher NO conversion for the 8Fe‐8Mn/Al2O3 catalyst. In addition, the SCR activity of the 8Fe‐8Mn/Al2O3 cata‐lyst was only slightly decreased in the presence of H2O and SO2, which indicated that the catalyst had better tolerance to H2O and SO2. The reaction temperature was crucial for the SO2 resistance of catalyst and the decrease of catalytic activity caused by SO2 was mainly due to the sulfate salts formed on the catalyst.

Recent developments in the use of single-atom catalysts for water splitting

Electrochemical water splitting is regarded as the most promising approach to produce hydrogen.However,the sluggish electrochemical reactions occurring at the anode and cathode,namely,the oxygen evolution reaction(OER)and the hydrogen evolution reaction(HER),respectively,consume a tremendous amount of energy,seriously hampering its wide application.Recently,single-atom catalysts(SACs)have been proposed to effectively enhance the kinetics of these two reactions.In this minireview,we focus on the recent progress in SACs for OER and HER applications.Three classes of SACs have been reviewed,i.e.,alloy-based SACs,carbon-based SACs and SACs supported on other compounds.Different factors affecting the activities of SACs are also highlighted,including the inherent element property,the coordination environment,the geometric structure and the loading amount of metal atoms.Finally,we summarize the current problems and directions for future development in SACs.

Interatomic diffusion in Pd-Pt core-shell nanoparticles

Pt monolayer-based core-shell catalysts have garnered significant interest for the application of low temperature fuel cell technology as their use may enable a decreased loading of Pt while still providing sufficient current density to meet volumetric requirements. One promising candidate in this class of materials is a Pd@Pt core-shell catalyst, which shows enhanced activity toward oxygen reduction reaction(ORR). One concern with the use of Pd@Pt, however, is the durability of the core-shell structure as Pd atoms are thermodynamically favored to migrate to the surface. The pathway of the migration has not been systematically studied. The current study explores the stability of this structure to thermal annealing and probes the effect of this heat treatment on the catalyst surface structure and its oxygen reduction activity. It was found that surface alloying between Pd and Pt occurs at temperatures as low as 200 °C, and significantly alters the structure and ORR catalytic activity in the range of 200–300 °C. Our results shed lights on the thermal induced interatomic diffusion in all core-shell and thin film structures.

Heterogeneous N-coordinated single-atom photocatalysts and electrocatalysts

Single-atom catalysts(SACs)have been widely used in heterogeneous catalysis owing to the maximum utilization of metal-active sites with controlled structures and well-defined locations.Upon tailored coordination with nitrogen atom,the metal-nitrogen(M-N)-based SACs have demonstrated interesting physical,optical and electronic properties and have become intense in photocatalysis and electrocatalysis in the past decade.Despite substantial efforts in constructing various M–N-based SACs,the principles for modulating the intrinsic photocatalytic and electrocatalytic performance of their active sites and catalytic mechanism have not been sufficiently studied.Herein,the present review intends to shed some light on recent research made in studying the correlation between intrinsic electronic structure,catalytic mechanism,single-metal atom(SMA)confinement and their photocatalytic and electrocatalytic activities(conversion,selectivity,stability and etc).Based on the analysis of fundamentals of M–N-based SACs,theoretical calculations and experimental investigations,including synthetic methods and characterization techniques,are both included to provide an integral understanding of the underlying mechanisms behind improved coordination structure and observed activity.Finally,the challenges and perspectives for constructing highly active M–N based photocatalysis and electrocatalysis SACs are provided.In particular,extensive technical and mechanism aspects are thoroughly discussed,summarized and analyzed for promoting further advancement of M-N-based SACs in photocatalysis and electrocatalysis.

Modulating the microenvironment structure of single Zn atom:ZnN_(4)P/C active site for boosted oxygen reduction reaction

The electronic structure of catalytic active sites can be influenced by modulating the coordination bonding of the central single metal atom,but it is difficult to achieve.Herein,we reported the single Zn-atom incorporated dual doped P,N carbon framework(Zn-N_(4)P/C)for ORR via engineering the surrounding coordination environment of active centers.The Zn-N_(4)P/C catalyst exhibited comparable ORR activity(E_(1/2)=0.86 V)and significantly better ORR stability than that of Pt/C catalyst.It also shows respectable performance in terms of maximum peak power density(249.6 mW cm^(-2)),specific capacitance(779 mAh g^(-1)),and charge-discharge cycling stability for 150 hours in Zn-air battery.The high catalytic activity is attributed to the uniform active sites,tunable electronic/geometric configuration,optimized intrinsic activity,and faster mass transfer during ORR-pathway.Further,theoretical results exposed that the Zn-N_(4)P configuration is more electrochemically active as compared to Zn-N_(4) structure for the oxygen reduction reaction.

Application of atomic layer deposition in fabricating high-efficiency electrocatalysts

Electrocatalysis is a promising approach to clean energy conversion due to its high efficiency and low environmental pollution. Noble metal materials have been studied to show high activity toward electrocatalyltic reactions, although such applications remain restricted by the high cost and poor durability of the noble metals. By precisely adjusting the catalyst composition, size, and structure, electrocatalysts with excellent performance can be obtained. Atomic layer deposition(ALD) is a technique used to produce ultrathin films and ultrafine nanoparticles at the atomic level. It possesses unique advantages for the controllable design and synthesis of electrocatalysts. Furthermore, the homogenous composition and structure of the electrocatalysts prepared by ALD favor the exploration of structure-reactivity relationships and catalytic mechanisms. In this review, the mechanism, characteristics, and advantages of ALD in fabricating nanostructures are introduced first. Subsequently, the problems associated with existing electrocatalysts and a series of recently developed ALD strategies to enhance the activity and durability of electrocatalysts are presented. For example, the deposition of ultrafine Pt nanoparticles to increase the utilization and activity of Pt, fabrication of core–shell, overcoat, nanotrap, and other novel structures to protect the noble-metal nanoparticles and enhance the catalyst stability. In addition, ALD developments in synthesizing non-noble metallic electrocatalysts are summarized and discussed. Finally, based on the current studies, an outlook for the ALD application in the design and synthesis of electrocatalysts is presented.

Supported dual-atom catalysts: Preparation, characterization, and potential applications

Developing sustainable and clean electrochemical energy conversion technologies is a crucial step in addressing the challenges of energy shortage and environmental pollution. Exploring and developing new electrocatalysts with excellent performance and low cost will facilitate the commercial use of these energy conversion technologies. Recently, dual-atom catalysts(DACs) have attracted considerable research interest since they exhibit higher metal atom loading and more flexible active sites compared to single-atom catalysts(SACs). In this paper, the latest preparation methods and characterization techniques of DACs are systematically reviewed. The advantages of homonuclear and heteronuclear DACs and the catalytic mechanism and identification technologies between the two DACs are highlighted. The current applications of DACs in the field of electrocatalysis are summarized. The development opportunities and challenges of DACs in the future are prospected. The ultimate goal is to provide new ideas for the preparation of new catalysts with excellent properties by customizing diatomic catalysts for electrochemical applications.

Electrocatalytic generation of hydrogen peroxide on cobalt nanoparticles embedded in nitrogen-doped carbon

Electrocatalytic reduction of oxygen is a growing synthetic technique for the sustainable production of hydrogen peroxide(H_(2)O_(2)).The current challenges concern seeking low-cost,highly active,and selective electrocatalysts.Cobalt-nitrogen-doped carbon containing catalytically active cobalt-nitrogen(Co-N_(x))sites is an emerging class of materials that can promote the electrochemical generation of H_(2)O_(2).Here,we report a straightforward method for the preparation of cobalt-nitrogen-doped carbon composed of a number of Co-N_(x)moieties using low-energy dry-state ball milling,followed by controlled pyrolysis.This scalable method uses inexpensive materials containing cobalt acetate,2-methylimidazole,and Ketjenblack EC-600JD as the metal,nitrogen,and carbon precursors,respectively.Electrochemical measurements in an acidic medium show the present material exhibits a significant increase in the oxygen reduction reaction current density,accompanied by shifting the onset potential into the positive direction.The current catalyst has also demonstrated an approximate 90%selectivity towards H_(2)O_(2)across a wide range of potential.The H_(2)O_(2)production rate,as measured by H_(2)O_(2)bulk electrolysis,has reached 100 mmol g_(cat).^(–1)h^(–1)with high H_(2)O_(2)faradaic efficiency close to 85%(for 2 h at 0.3 V vs.RHE).Lastly,the catalyst durability has been tested(for 6 h at 0.3 V vs.RHE).The catalyst has shown relatively consistent performance,while the overall faradic efficiency reaches approximate 85%throughout the test cycle indicating the promising catalyst durability for practical applications.The formed Co-N_(x)moieties,along with other parameters,including the acidic environment and the applied potential,likely are the primary reasons for such high activity and selectivity to H_(2)O_(2)production.

Electrocatalytic H_(2)O_(2)generation for disinfection

Epidemics are threatening public health and social development.Emerging as a green disinfectant,H_(2)O_(2)can prevent the breakout of epidemics in migration.Electrochemical H_(2)O_(2)production powered by renewable electricity provides a clean and decentralized solution for on-site disinfection.This review firstly discussed the efficacy of H_(2)O_(2)in disinfection.Then necessary fundamental principles are summarized to gain insight into electrochemical H_(2)O_(2)production.The focus is on exploring pathways to realize a highly efficient H_(2)O_(2)production.Progress in advanced electrocatalysts,typically single-atom catalysts for the two-electron oxygen reduction reaction(2e−ORR),are highlighted to provide high H_(2)O_(2)selectivity design strategies.Finally,a rational design of electrode and electrolytic cells is outlined to realize the on-site disinfection.Overall,this critical review contributes to exploiting the potentials and constraints of electrochemical H_(2)O_(2)generation in disinfection and pinpoints future research directions required for implementation.

Structural evolution of Pt‐based oxygen reduction reaction electrocatalysts

The commercialization of proton exchange membrane fuel cells(PEMFCs)could provide a cleaner energy society in the near future.However,the sluggish reaction kinetics and harsh conditions of the oxygen reduction reaction affect the durability and cost of PEMFCs.Most previous reports on Pt-based electrocatalyst designs have focused more on improving their activity;however,with the commercialization of PEMFCs,durability has received increasing attention.In-depth insight into the structural evolution of Pt-based electrocatalysts throughout their lifecycle can contribute to further optimization of their activity and durability.The development of in situ electron microscopy and other in situ techniques has promoted the elucidation of the evolution mechanism.This mini review highlights recent advances in the structural evolution of Pt-based electrocatalysts.The mechanisms are adequately discussed,and some methods to inhibit or exploit the structural evolution of the catalysts are also briefly reviewed.

Single atom‐based catalysts for electrochemical CO_(2) reduction

Electrochemical CO_(2) reduction reaction(CO_(2)RR),powered by renewable energy,emerges as a promising approach against environmental issues and energy crisis by converting CO_(2) into val‐ue‐added chemicals.Single atom catalysts(SACs)with isolated metal atoms dispersed on supports exhibit outstanding performance for CO_(2) electroreduction,because of their strong single at‐om‐support interactions,maximum metal utilization and excellent catalytic activity.However,SACs suffer from agglomeration of particles,low metal loading,and difficulty in large‐scale production.In addition,molecular catalysts as another single atom‐based catalyst,consisting of ligands molecules connected to metal ions,exhibited similar metal‐nitrogen(M‐N)active centers as that in met‐al‐nitrogen‐carbon(M‐N‐C)SACs,which were highly active to CO_(2) reduction due to their well‐defined active sites and tunability over the steric and electronic properties of the active sites.Nonetheless,molecular catalysts are challenged by generally moderate activity,selectivity and sta‐bility,poor conductivity and aggregation.Many works have been devoted to overcoming these is‐sues of SACs and molecular catalysts for efficient CO_(2)RR,but only limited reviews for systematic summary of their fabrication,application,and characterizations,which were highlighted in this review.Firstly,we summarize recent advanced strategies in preparing SACs for CO_(2)RR,including wet‐chemistry approaches(defect engineering,spatial confinement,and coordination design),other synthetic methods and large‐scale production of SACs.Besides,electrochemical applications of SACs and molecular catalysts on CO_(2)RR are discussed,which involved the faradaic efficiency and partial current density of the desired product as well as the catalyst stability.In addition,ex‐situ and in‐situ/operando characterization techniques are briefly assessed,benefiting probing the active sites and understanding the CO_(2)RR catalytic mechanisms.Finally,future directions for the devel‐opment of single atom‐based catalysts(SACs,molecular catalysts)are pointed out.

Structural and interfacial engineering of well‐defined metal‐organic ensembles for electrocatalytic carbon dioxide reduction

Electrochemical carbon dioxide reduction(CO_(2)RR)has been generally regarded as green technologies that can convert renewable energy such as sunlight and wind into fuels and valuable chemicals.However,the large‐scale implementation of CO_(2)RR is severely hindered by the lack of high‐performance CO_(2)RR electrocatalysts.Heterogeneous molecular catalysts and metal‐organic framework with well‐defined structure and high tunability of the metal centers and ligands show great promise for CO_(2)RR in terms of both fundamental understanding and practical application.Here,structural and interfacial engineering of these well‐defined metal‐organic ensembles is summarized.This review starts from the fundamental electrochemistry of CO_(2)RR and its evaluation criteria,and then moves to the heterogeneous molecular catalysts and metal‐organic framework with emphasis on the engineering of metal centers and ligands,their interaction with supports,as well as in situ reconstruction of metal‐organic ensembles.Summary and outlook are present in the end,with the hope to inspire and provoke more genuine thinking on the design and fabrication of efficient CO_(2)RR electrocatalysts.

A theoretical study of electrocatalytic ammonia synthesis on single metal atom/MXene

Electrocatalytic ammonia synthesis under mild conditions is an attractive and challenging process in the earth’s nitrogen cycle,which requires efficient and stable catalysts to reduce the overpotential.The N2 activation and reduction overpotential of different Ti3C2O2-supported transition metal(TM)(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Cd,and Au)single-atom catalysts have been analyzed in terms of the Gibbs free energies calculated using the density functional theory(DFT).The end-on N2 adsorption was more energetically favorable,and the negative free energies represented good N2 activation performance,especially in the presence Fe/Ti3C2O2(﹣0.75 eV).The overpotentials of Fe/Ti3C2O2,Co/Ti3C2O2,Ru/Ti3C2O2,and Rh/Ti3C2O2 were 0.92,0.89,1.16,and 0.84 eV,respectively.The potential required for ammonia synthesis was different for different TMs and ranged from 0.68 to 2.33 eV.Two possible potential-limiting steps may be involved in the process:(i)hydrogenation of N2 to*NNH and(ii)hydrogenation of*NH2 to ammonia.These catalysts can change the reaction pathway and avoid the traditional N–N bond-breaking barrier.It also simplifies the understanding of the relationship between the Gibbs free energy and overpotential,which is a significant factor in the rational designing and large-scale screening of catalysts for the electrocatalytic ammonia synthesis.