A First-principles Study Of The Effect Of Non-metallic Atoms Doped On The Surface Of Metallic Nickel On Hydrogen Evolution Reaction

Hydrogen has attracted widespread attention as a clean and efficient energy source.Metal nickel is highly abundant in nature and has good catalytic activity for hydrogen evolution reaction.However,the surface of the metallic Ni is too active,which is not conducive to desorption of H2 from the surface.Experiments have shown that non-metal atoms can "poison" the surface of metallic nickel and decrease the activity of Ni surfaces,which increase the catalytic activity of the hydrogen evolution reaction.In theory,The HER activity of the different non-mental alloys with Ni has been performed,but no systematic analysis of all reported non-metal atoms has been performed.Therefore,this paper will systematically study the influence of the adsorption sites and coverage of non-metal atoms on the metal surface of the hydrogen evolution reaction.In this thesis,the Gibbs free energy of alloys formed from metallic nickel and non-metal atoms is studied by first-principles method.The electronic properties and orbital interactions are analyzed by Bader charge,local density and work function.The research content of this paper consists of four parts.The first part mainly summarizes the research background,research significance and research status of metal electrocatalyst,and determines the importance and necessity of the research content.The second part introduces the theoretical basis,related methods and software;In part,the effect of metal nickel surface on the hydrogen evolution reaction was studied.The catalytic activity was judged by calculating the Gibbs free energy.The charge transfer and orbital interaction were analyzed by using the Bader charge,exchange current density and local density of states.The electrocatalytic activity of alloys(NiX)formed of non-metal atoms(B,C,Si,N,P,As,S,Se,Te,F,Cl,Br and I)with metallic nickel was investigated in four parts.Calculate the Gibbs free energy of different systems and analyze its work function and local state density,and study the interaction between the electrode's ability to ionize electrons and the orbit.The main findings are summarized as follows:(1)The effect of the partial oxidation of metallic nickel on the hydrogen evolution reaction was studied.The results show that the ?GH*of the metallic nickel is-0.29 eV,which indicates that the metallic nickel electrode is too active,which limits the desorption of H2 from the metal surface.When the surface of the metallic nickel is slightly oxidized((?)=2/8,3/8,4/8,5/8 and 7/8 ML,?GH*are-0.14,-0.05,0.14,0.19 and 0.50 eV),we find that ?AGH*is close to 0,indicating that the metal nickel surface has a lower oxygen concentration than the pure metallic nickel and high concentration.Oxidized metallic nickel has relatively good catalytic activity,mainly because the oxygen concentration on the surface of metallic nickel is low,the number of active sites adsorbed by H atoms is large,and these active sites are at the Ni/NiO interface,so low concentration oxidized metallic nickel has relatively good catalytic activity.By analyzing its electronic properties,we found that the surfaces of the oxidized metal nickel,nickel atoms transfer electrons to the surface oxygen atoms,weakening the interaction between H atoms and metal nickel atoms,so it has better activity.(2)We explored other non-metal atoms(B,C,Si,N,P,As,S,Se,Te,F,Cl,Br and I)the effect of an alloy(NiX)formed with metallic nickel on the hydrogen evolution reaction.Because the oxygen concentration on the surface of metallic nickel is difficult to control in the experiment.The results show that when the non-metal atom coverage of the metal nickel surface is 1/9 ML,the ?GH*of NiS,NiSe,NiTe and Nil are-0.180,-0.179,-0.182 and-0.198 eV,respectively,it has better catalytic activity for HER;the main reason is that the work function of NiS,NiSe,NiTe and Nil is lower than that of pure metal nickel,which is more likely to ionize electrons to give H protons in solution.When the coverage of non-metal atoms on the surface metal nickel is 2/9 ML,the ?GH*of NiS,NiSe,Nil and NiTe are-0.147,-0.152 eV,-0.259 and-0.207 eV.The NiS and NiSe are closer to 0 than the 1/9 ML,and is beneficial to H2 release.For Nil and NiTe,which are more stable than the 1/9 ML,and which is not conducive to H2 production.Through the density analysis of states,it can be seen that in the vicinity of the Fermi level,due to the hybridization between the d orbital of the metallic Ni and the p orbital of the nonmetal atom,the adsorption capacity of the metal to the H atom is weakened.Therefore,it has relatively good catalytic activity.