Constructing Rh-Rh3+modified Ta2O5@TaON@Ta3N5with special double n-n mutant heterojunctions for enhanced photocatalytic H2-evolution

Abstract

A multiple core-shell heterostructure Rh-Rh3+ modified Ta2O5@TaON@Ta3N5 nanophotocatalyst was successfully constructed through nitriding Rh3+-doped Ta2O5 nanoparticles, which exhibited a much higher carrier separation efficiency about one order of magnitude higher than the Ta2O5@Ta3N5 precursor, and thus an excellent visible light photocatalytic H2-evolution activity (83.64 μmol g-1 h-1), much superior to that of Rh anchored Ta2O5@TaON (39.41 μmol g-1 h-1), and improved stability due to the residual Rh-O/N in the Ta3N5 shell layer. Rh-modifying significantly extended light absorption to the overall visible region. Localized built-in electric fields with hierarchical potential gradients at the multiple interfaces including a Rh/Ta3N5 Schottky junction and double n-n Ta3N5/TaON/Ta2O5 mutant heterojunctions, drove charge carriers to directionally transfer from inside to outside, and efficiently separate. Enhanced photoactivity was ascribed to a synergetic effect of improved light absorption ability, increased carrier separation efficiency, and accelerated surface reaction. A promising strategy of developing excellent Ta3N5-based photocatalysts for solar energy conversion is provided by constructing double n-n mutant heterojunctions. This journal is