Hydrogen Evolution/Spillover Effects Of Single Atom On Low Dimensional Materials Based On First Principles Calculations

With the development of economy and the growth of population,the problem of energy shortage is becoming more and more serious.The development of sustainable energy has been paid more attention.By photocatalytic water splitting to convert solar energy into hydrogen energy provides a new idea for people.Looking for suitable photocatalytic materials has also become the focus of research.Based on this background,our work focuses on the application prospect of photocatalytic water splitting,and makes a more detailed description of the principle of photocatalytic water splitting.In the field of heterogeneous catalysis,monatomic catalysis,as a frontier research field,has attracted extensive attention due to its high atom utilization,complex catalytic mechanism and excellent catalytic performance.However,although some progress has been made,it is still a long way to go to use non noble metals instead of noble metals as catalysts in chemical reactions.Based on the framework of density functional theory,we studied the effect of single atom on photocatalytic hydrogen evolution and hydrogen spillover on the surface of low dimensional materials.The typical g-C₃N₄material is selected in the two-dimensional materials.The reason of its poor catalytic performance was analyzed from the point of view of first principle calculation.Combined with the previous research experience,Cu single atom was selected as the supporting atom,and its possible existence form was analyzed.Taking the calculation of Gibbs free energy of hydrogen evolution reaction as the breakthrough point,it was comprehensively clarified that the g-C₃N₄material carried by Cu single atom has a positive role in improving the hydrogen evolution ability of intrinsic g-C₃N₄.From the point of view of reconstructing its surface charge,it is found that the proper charge transfer of the Cu single atom to the surrounding N atoms makes the Cu single atom become the catalytic active center,which enhances the capture of protons in the solution,thus promoting its hydrogen evolution performance.In the three-dimensional materials,we chose anatase Ti O₂（101）as the research object.We have studied the hydrogen evolution in a Co single atom（SA）system supported by anatase Ti O₂and studied the hydrogen spillover effect by first principles calculations.There are two stable forms of Co atoms on the surface of anatase Ti O2（101）,that is,different binding effects are produced by adsorption and substitution.The hydrogen evolution activity of Co in the surface gap is better than that of bulk Co.The hydrogen evolution reaction takes place on the partially hydrogenated Co₁/Ti O₂surface,in which the Co atom（SA Co）and the adjacent O are the active sites.In H₂atmosphere,the substitution of Co for Ti promotes the formation of O vacancies and the reduction of Ti⁴⁺to Ti³⁺,indicating that the hydrogen spillover effect is enhanced.Through the calculation of reaction kinetics,the possible catalytic mechanisms of two kinds of SA catalysts were proposed.This work highlights the complexity and diversity of the limiting role of transition metal SA in oxides,and broadens its application in catalysis and defect engineering.