ScSeI Monolayer for\nPhotocatalytic Water Splitting

We theoretically identify the ScSeI monolayer as a promising\nnew\n2D material for photocatalysis through first-principles calculations.\nThe most notable feature is the significant difference in carrier\nmobility, with electron mobility in the horizontal direction being\n20.66 times higher than hole mobility, minimizing electron–hole\nrecombination. The ScSeI monolayer exhibits a bandgap of 2.51 eV,\nwith the valence band maximum at −6.37 eV and the conduction\nband minimum at −3.86 eV, meeting the requirements for water\nsplitting. Phosphorus doping lowers the Gibbs free energy by 1.63\neV, enhancing the catalytic activity. The ScSeI monolayer achieves\na hydrogen production efficiency of 17%, surpassing the commercial\nthreshold of 10% and shows excellent mechanical, thermal, and dynamic\nstability, indicating feasibility for experimental synthesis and practical\napplication. Additionally, the monolayer maintains its photocatalytic\nproperties under tensile strain (−6% to 6%) and in aqueous\nenvironments, reinforcing its potential as an effective photocatalyst.\nBased on these findings, we believe the ScSeI monolayer is a highly\npromising photocatalyst.