Size modulation of plasmonic In2O3 nanocube optimized photocatalytic H2 evolution over stack g–C3N4–In2O3 heterojunction

Abstract

A strategy of tuning the size of In2O3 nanocube was employed to change the surface property of g–C3N4–In2O3 heterojunction to boost its photocatalytic H2 production. In the type II g–C3N4–In2O3 heterojunction, the change on the size of In2O3 nanocube (30, 60 and 120 nm) could regulate visible light utilization ability and photoelectric conversion efficiency of photogenerated charge carriers. The directional transfer of charge carriers caused the accumulation of photoexcited electron in plasmonic In2O3 and localized electric field enhancement. The intensity and spatial distribution of localized electric field could be tuned by the adjustable size of In2O3 nanocube. Therefore, the obtained g–C3N4–In2O3 heterojunction with an optimal size of In2O3 nanocube (60 nm) exhibited supreme photocatalytic H2 evolution rate of 3.1 mmol h−1 g−1 with a high apparent quantum efficiency of 5.27%, which was 7.5 times higher than that of bare g-C3N4 nanosheet (0.4 mmol h−1 g−1).