Halogenation as a novel scheme for enhanced photocatalytic activity in AlSb monolayers: a first-principles study

Abstract

We proposed a novel scheme for achieving enhanced photocatalytic activity in two-dimensional nanomaterials. Traditionally, substitution doping and employing van der Waals heterostructures have been popular methods for enhancing photocatalytic activity. We demonstrated here, using ab initio calculations, that halogen functionalization could be an excellent scheme for enhancing photocatalytic activity in AlSb monolayers. Bromine and iodine functionalized AlSb monolayers were energetically and dynamically stable and had excellent band alignments that can facilitate photocatalytic water splitting for hydrogen production. The calculation of Gibbs free energy along the photocatalytic pathway revealed that there is only a very low barrier for hydrogen or oxygen evolution reactions. The solar-to-hydrogen efficiency reached ∼30%, with a carrier utilization efficiency reaching 40%. Our findings open a new avenue for research employing photocatalysis to generate green energy.