| In 2011,researchers prepared an atomically dispersed Pt catalyst for the first time,and proposed the concept of a single-atom catalyst:all metal components are supported catalysts that exist as single-atom dispersion.Since then,single-atom catalysts(SACs)have attracted attention for their unique advantages of taking advantage of all metal atoms,uniform active sites and significant selectivity,as well as greater catalytic activity than traditional metal nanoparticles.However,with the increase of transition metal(TM)atomic loading,the cohesion energy of the cluster destroys the adsorption of single atoms on the substrate,resulting in the tendency of TM atoms to cluster and significantly decrease the catalytic performance.The boronene monoatomic layer(BM)is a novel twodimensional material composed of triangular and hexagonal holes that can serve as atomic anchor anchors for transition metal(TM)atoms,causing TM atoms to disperse independently without forming clusters.Therefore,boronene can be used as a carrier for SACs,which are widely used in renewable energy conversion,electrochemistry and other fields.and the relevant studies have shown that Ni/β12-BM loaded with isolated Ni atoms can be used for the overall water splitting reaction,and it is theoretically predicted that Ni/β12-BM has good catalytic performance in hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),the synergistic effect between adjacent metal atoms can effectively improve the catalytic activity of oxygen evolution reaction(OER)and oxygen reduction reaction(ORR),inducing bifunctional properties.Therefore,diatomic catalysts(DACs)can be used as a powerful tool to achieve high efficiency and selectivity in catalytic reactions,which has high research significance and application prospects.Based on density functional theory,this study will study the 3d transition bimetallic atom TM1TM2(TM1=Fe/Ni,TM2=Cr-Cu)loaded on β12-BM for water splitting to explore multifunctional HER,OER/ORR diatomic catalysts.The main conclusions are as follows:β12-BM can be used as a good carrier for diatomic catalysts.Our study shows that most DACs have good catalytic performance for hydrogen evolution reactions(HER),and the synergy between NiCu metal atoms makes it an effective diatomic catalyst for HER with low Gibbs free energy for hydrogen adsorption,very close to 0(～0.0049 eV).The theoretical prediction of HER catalytic performance is better than that of Pt(110),MoS2,and naked boronene without adsorbing metal atoms,and the Hamilton population(COHP)analysis of crystal orbital shows that the bonding level between the atom and the adjacent site decreases,and the change of the composite-iCOHP value indicates bonding.At the same time,from the Bader charge analysis,it can be seen that more electrons are transferred from atoms to the boron monoatomic layer(BM),and the electrostatic interaction is stronger.This study has preliminarily explored the catalytic performance ofβ12 boronene surface adsorption of bimetallic atoms for hydrogen evolution reaction(HER),which can provide theoretical guidance for experiments and promote the development of boronene related research in HER.Based on density functional theory,we designed a series of borene surface-supported transition metal diatomic catalysts TM1TM2/β12-BM(TM1=Fe/Ni,TM2=Cr-Cu)to study the influence of different metal combinations on the catalytic performance of OER and ORR.The results show that FeNi DAC at the Ni adsorption site have a low overpotential(0.43/0.55 V)in both OER and ORR,which can be used as a good bifunctional catalyst.Due to the synergistic effect between the diatoms,the catalytic performance is better than that of the corresponding Ni or Fe SAC.Based on the scale relationship between the adsorption free energy of oxygen-containing intermediates(OH*、0*、OOH*),we established contour maps and volcanic maps,and further explored the trend of OER/ORR performance.Regarding its bonding mechanism and origin of activity,its relationship with adsorption was analyzed by using iCOHP and d band center descriptors.In addition,we designed a new descriptor to efficiently and quickly screen out the best catalyst.This study provides a complete description of the OER and ORR performance of TM1TM2/β12-BM performance,and provides theoretical guidance for the development of novel highefficiency electrocatalysts for future energy conversion and storage. |
