Theoretical Study On The Electrocatalytic Reduction Of Carbon Monoxide On Hexagonal Boron Nitride Confined Copper Based Surface

A large number of carbon dioxide（CO₂）is emitted into the atmosphere,causing harmful effects on the global environment.Therefore,reducing the impact of CO₂on the environment and effectively utilizing CO₂is very important.Recently,CO₂reduction has received a lot of attention,where electrocatalytic carbon dioxide reduction reactions（CO₂RR）can not only reduce CO₂in the air,but also convert CO₂into high added value energy source and chemicals.As carbon monoxide（CO）is not only a low-cost product that is increasingly readily available from electrocatalyzed carbon dioxide reduction reactions,but also a key intermediate in the process of electrocatalytic reduction of carbon dioxide into high added value products.Therefore,directly using CO as the initial raw material for reduction reactions has attracted the interest of researchers.Designing and developing efficient electrocatalysts for direct electrocatalytic carbon monoxide reduction reaction（CORR）to reduce CO to other high added value fuels and chemicals is highly desirable.Copper-based catalysts can electrocatalyst CO reduction to hydrocarbon efficiently,however high overpotential and low selectivity limit their large-scale industrial application.By constructing a suitable confined microenvironment on the surface of the catalyst,effective regulation of surface chemical reactions can be achieved,thereby improving its catalytic performance and selectivity.This paper investigates the effect of h-BN confinement on the electrocatalytic CO reduction activity of Cu（111）surface using hexagonal boron nitride（h-BN）confined Cu（111）surface（h-BN/Cu（111））.In addition,three kinds of transition metals were selected to control the electronic structure of copper-based surface,achieving space confinement and synergistic catalysis of the surface active site.In this paper,the influence of the h-BN confinement and confinement space size（d=5.0～6.0（?））on the electrocatalytic performance of Cu（111）catalyst for CO reduction was systematically studied by the density functional theory（DFT）method.The results showed that in the h-BN/Cu（111）catalyst,as the confinement space decreased,the interaction between Cu（111）adsorbed CHO structure and h-BN increased,and the system energy decreased,i.e.E_G（*CHO）decreased,resulting in an increase in electrocatalytic CO reduction reaction activity on h-BN/Cu（111）with a height range of 5.0～6.0（?）and higher than that on Cu（111）catalyst.h-BN/Cu（111）with d=5.0（?）showed the best catalytic performance for electrocatalytic CO reduction,which could reduce CO to methane or methanol.The potential determination step was*CO→*CHO,and the limiting potential is-0.78 V.In addition,h-BN coverage does not enhance the hydrogen evolution reaction（HER）activity.The selectivity of the h-BN/Cu（111）catalyst for electrocatalytic CO reduction reaction is higher than that of the competitive HER process.This study provides a new method for improving catalytic activity by covering copper based surfaces with two-dimensional materials to form a confined space.The DFT method was used to investigate the effect of transition metal atoms（Pt、Zn and Ni）doping on the electrocatalytic performance of h-BN/Cu（111）for CORR.It was found that doping different transition metals had different effects on the catalytic activity.h-BN/Pt Cu（111）showed the best CORR catalytic activity,which could reduce CO to methane.The potential determination step was*CO→*CHO,and the limiting potential was only-0.36 V.The electronic structure analysis shows that there is charge transfer between Pt and Cu,and there is electronic interaction.Pt gets the charge to become the active site.The d-band center of Pt doped transition metal atoms in the h-BN/Pt Cu（111）system shifts upwards compared to the d-band center of pure Pt,the interaction between the key intermediates and the catalyst surface is enhanced,ultimately leading to the ultra-high catalytic activity of the h-BN/Pt Cu（111）catalyst.In addition,the catalytic activity of h-BN/MCu（111）（M=Pt、Zn、Ni）is significantly enhanced compared with the transition metal doped Cu（111）surface.This is because the confinement effect between the alloy surface and the h-BN layer makes the binding energy of CHO at the h-BN/MCu（111）interface lower than that on the corresponding transition metal-doped Cu（111）surface,stabilizing the key intermediate.The selectivity of h-BN/MCu（111）for CO electrochemical reduction reaction is higher than that of competing the HER process,and has good CORR selectivity.This division of labor provides theoretical guidance for the in-depth understanding of the relationship between transition metal doping and the catalytic activity of electrocatalytic CORR.