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

A strategy of tuning the size of In 2 O 3 nanocube was employed to change the surface property of g–C 3 N 4 –In 2 O 3 heterojunction to boost its photocatalytic H 2 production. In the type II g–C 3 N 4 –In 2 O 3 heterojunction, the change on the size of In 2 O 3 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 In 2 O 3 and localized electric field enhancement. The intensity and spatial distribution of localized electric field could be tuned by the adjustable size of In 2 O 3 nanocube. Therefore, the obtained g–C 3 N 4 –In 2 O 3 heterojunction with an optimal size of In 2 O 3 nanocube (60 nm) exhibited supreme photocatalytic H 2 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-C 3 N 4 nanosheet (0.4 mmol h −1  g −1 ).