Designing And Modulating Of Novel Two-dimensional Photo- And Electrocatalysts

Explore green and sustainable energy resources to alternative and relive the usage of traditional fossil energy has get more and more attentions nowadays.The studies and explorations of photocatalyst and electrocatalyst become one of the effective methods to solve the problems above.Hence,it is of great significance to investigate the electronic,geometric,and catalytic properties of photo/electrocatalysts theoretically to guide the synthesis of photo/electrocatalyst in experiments.Since the successful exfoliation of two-dimensional（2D）graphene in 2004,2D based photocatalyst and electrocatalyst has been widely studied.However,excellent 2D based catalysts are rare.Hence,explore novel 2D based electro/photocatalyst is of great significance in future.In recent year,the studies of novel 2D-based electro/photocatalyst researches not only widen the application of catalysts for 2D materials but could make a guidance to synthesis excellent catalyst experimentally.Meantime,the exploration of novel 2D materials could make new realization for the designing of photo/electrocatalyst,exploiting of reaction pathway,and enhancing of catalytic efficiency.Therefore,in this work,we aim to design novel 2D based photo-and electrocatalyst to investigate their geometric,electronic,catalytic properties,and illustrate their catalytic behaviors.And the corresponding works can be concluded as follow:Systematical investigations were performed for Ga PS₂Se₂by studying the geometric,stable,electronic,optical,and photocatalytic properties.Results demonstrate that Ga PS₂Se₂ is a stable 2D material,which exhibits anisotropic properties.Electronic properties revealed that the bandgap of Ga PS₂Se₂ is 2.64 e V using the hybrid function（HSE）.Notably,it also shows anisotropic carrier mobility,with the carrier mobility of 284.61/37.60 cm²V^-1S^-2 for the electrons and 528.83/550.63cm²V^-1S^-2 for the holes,which is good for the photocatalytic water splitting process.Besides,optical properties calculation revealed that it owns excellent absorption rate within different absorption rate along xx and yy directions,further proved its importance in photocatalytic field.In addition,the optical and electronic properties can be well tuned under the strain engineering.Finally,we investigated the photocatalytic Gibbs free energy step of Ga PS₂Se₂ monolayer,results demonstrated that the photoinduced OER and HER could spontaneously occur under the modulation of strain（2%tensile strain）and p H values（p H=3）.In summary,Ga PS₂Se₂ monolayer is a potential photocatalyst for water splitting.Systematical studies were performed for transitional metal doped Al P monolayer to filtrate excellent bifunctional oxygen electrocatalyst by high through put screening.16 kinds single-transitional metal（Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zr,Mo,Ru,Rh,Ag,Hf,Pt,Au）and nitrogen doping in 2D defected Al P monolayer for searching optimized bifunctional oxygen electrocatalyst.Results demonstrated that Co@V_Al-2N_P-Al P and Ni@V_Al-2N_P-Al P systems exhibit excellent bifunctional OER/ORR catalytic performance with the overpotential of 0.38/0.25 V and 0.23/0.39 V,respectively.Then the tendency,origin of the OER and ORR systematically analysis,among the analysis,machine learning was implemented for descriptor searching,It was found that the charge transfer between the transition metal and the substrate as well as the number of d orbital electrons of transition metal can well describe the origin of the catalytic performance.In conclusion,this work screened kinds of high catalytic electrocatalyst used in oxygen electrocatalytic field,which is of great significance for the successful synthesis of those catalyst in experiment.Systematically explore metal-free dual atom electrocatalyst for nitrogen reduction reaction for the synthesized g-CN.The selected metal free atom is C,B and P atoms,which consisted into 6 systems,namely,B-B-@g-CN,B-C@g-CN,C-C@g-CN,B-P@g-CN,P-P@g-CN and P-C@g-CN.After ensuring their stability,the B-P@g-CN system was selected for later hydrogenation process.Results demonstrated that B and P co-doped g-CN system show excellent electrocatalytic performance with high activity of-0.18 V.By analyzing the catalytic origin for the substrate and the adsorption system,including Bader charge calculation,Charge density difference,density of state,COHP,we found that the empty sp² orbital of B and half-empty sp³ orbital of P exhibit different adsorption ability,leading to the two sites shows different adsorption strength,hence lower the energy barrier of N₂ activation,thus lower the limiting potential.,hence enhance the catalytic performance.After the N₂ adsorption,the synergistic effect between two active sites lowering the energy barrier during the N₂reduction.In summary,this work remits the use of conventional fossil fuel and avoid the CO₂emission,which can relieve the coming energy crisis.