The electronic structure,in particular the band edge position,of photocatalyst in presence of water is critical for photocatalytic water splitting.We propose a direct and systematic density functional theory(DFT)schem...The electronic structure,in particular the band edge position,of photocatalyst in presence of water is critical for photocatalytic water splitting.We propose a direct and systematic density functional theory(DFT)scheme to quantitatively predict band edge shifts and their microscopic origins for aqueous 2D photocatalyst,where thousands of atoms or more are able to be involved.This scheme is indispensable to correctly calculate the electronic structure of 2D photocatalyst in the presence of water,which is demonstrated in aqueous MoS_(2),GaS,InSe,GaSe and InS.It is found that the band edge of 2D photocatalysts are not rigidly shifted due to water as reported in previous studies of aqueous systems.Specifically,the CBM shift is quantitatively explained by geometric deformation,water dipole and charge redistribution effect while the fourth effect,i.e.,interfacial chemical contact,is revealed in the VBM shift.Moreover,the revealed upshift of CBM in aqueous MoS2 should thermodynamically help carriers to participate in hydrogen evolution reaction(HER),which underpin the reported experimental findings that MoS2 is an efficient HER photocatalyst.Our work paves the way to design 2D materials in general as low-cost and high-efficiency photocatalysts.展开更多
基金We thank Chen Hu,Zewen Wu,Haoran Chang,and Chenyi Zhou for useful discussions on the DFT calculation.This work was financially supported by the McGill Sustainability Systems Initiative(MSSI),Natural Sciences and Engineering Research Council of Canada(NSERC)and Emissions Reduction Alberta(H.G.and Z.M.)D.K.gratefully acknowledges the China Scholarship Council for a fellowship.We thank the High Performance Computing Center of McGill University,Calcul-Quebec and Compute Canada for computation facilitiesZ.M.acknowledges financial support from National Science Foundation(Grant CBET-1804458).
文摘The electronic structure,in particular the band edge position,of photocatalyst in presence of water is critical for photocatalytic water splitting.We propose a direct and systematic density functional theory(DFT)scheme to quantitatively predict band edge shifts and their microscopic origins for aqueous 2D photocatalyst,where thousands of atoms or more are able to be involved.This scheme is indispensable to correctly calculate the electronic structure of 2D photocatalyst in the presence of water,which is demonstrated in aqueous MoS_(2),GaS,InSe,GaSe and InS.It is found that the band edge of 2D photocatalysts are not rigidly shifted due to water as reported in previous studies of aqueous systems.Specifically,the CBM shift is quantitatively explained by geometric deformation,water dipole and charge redistribution effect while the fourth effect,i.e.,interfacial chemical contact,is revealed in the VBM shift.Moreover,the revealed upshift of CBM in aqueous MoS2 should thermodynamically help carriers to participate in hydrogen evolution reaction(HER),which underpin the reported experimental findings that MoS2 is an efficient HER photocatalyst.Our work paves the way to design 2D materials in general as low-cost and high-efficiency photocatalysts.
