Constructing Rh–Rh3+ modified Ta2O5@TaON@Ta3N5 with special double n–n mutant heterojunctions for enhanced photocatalytic H2-evolution

摘要

A multiple core–shell heterostructure Rh–Rh ~(3+) modified Ta _(2) O _(5) @TaON@Ta _(3) N _(5) nanophotocatalyst was successfully constructed through nitriding Rh ~(3+) -doped Ta _(2) O _(5) nanoparticles, which exhibited a much higher carrier separation efficiency about one order of magnitude higher than the Ta _(2) O _(5) @Ta _(3) N _(5) precursor, and thus an excellent visible light photocatalytic H _(2) -evolution activity (83.64 μmol g ~(?1) h ~(?1) ), much superior to that of Rh anchored Ta _(2) O _(5) @TaON (39.41 μmol g ~(?1) h ~(?1) ), and improved stability due to the residual Rh–O/N in the Ta _(3) N _(5) 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/Ta _(3) N _(5) Schottky junction and double n–n Ta _(3) N _(5) /TaON/Ta _(2) O _(5) 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 Ta _(3) N _(5) -based photocatalysts for solar energy conversion is provided by constructing double n–n mutant heterojunctions.