Investigating Photocatalytic Hydrogen Evolution Performance Of Single/Dual Atom Doped Violet Phosphorene From First-principles

Due to the rapid development of the economy,energy crisis and environmental pollution have been great threaten to human’s existence.Utilizing clean and sustainable energy in replacement of nonrenewable fossil fuels has become a key to solve these problems.Among the various new energy techniques,photocatalytic decomposition of water for hydrogen evolution reaction has garnered extensive attention and research interests.However,restricted by poor photo-absorption and low catalytic activity,the catalytic performance of current photocatalysts is still low,which is far from the mass production demand.As a novel 2D material,violet phosphorene has superiorities of non-toxic,stable,large specific surface area and tunable electronic properties,which is an ideal candidate for high-performance photocatalysts.In this work,by means of first principles calculations,we have systematically investigated the photocatalytic properties of single/dual atom doped violet phosphorene(VP)for hydrogen evolution reaction(HER),including the geometric structures,electronic properties,optical properties and hydrogen adsorption Gibbs free energies.We have found that:(1)Doing with single M-atom(M=Ag,Au,Cu,Ir,Os,Pd,Pt,Rh,Ru)would bring in new electronic states in band gap,significantly adjusting the band structures of VP,enhancing its optical absorption and regulating its redox potential.Electron transfer from the doped isolated M-atom to the semiconductor substrate would lead to decrease in work functions of VP,facilitating the carrier transfer dynamic,thus improving the photocatalytic performance for hydrogen evolution.Compared with pristine VP,the Gibbs free energies for HER of the single M-atom loaded VP systems decrease.Calculation results show that Pd/VP has the best catalytic hydrogen participation performance,with a low hydrogen adsorption Gibbs free energy of 0.0397 eV,which is much lower than that of pristine VP(1.28 eV).(2)Dual atoms loading on VP with M2 atoms(M=Ag,Au,Cu,Ir,Os,Pd,Pt,Rh,Ru)can induce multiple intermediate band states in the band gap of VP,leading to a significant adjustment of its band structures,which results in the widening of the range of optical absorption,enhancement of the optical absorption and reduced redox potential of VP.Furthermore,electron transfer from the loaded dual atoms to the semiconductor slab causes a decrease in the work function of VP.The dynamic of carriers transfer is therefore promoted,leading to the improved photocatalytic performance for hydrogen evolution.In comparison of pristine VP,the Gibbs free energy of the dual M2-atom loaded VP systems for HER is reduced.Among the tested systems,Ru2/VP exhibits the best catalytic hydrogen performance,with a low Gibbs free energy(-0.086 eV)for hydrogen adsorption,which is significantly lower than that of pristine VP(1.28 eV).