Construction of novel Sr0.4H1.2Nb2O6·H2O/g-C3N4 heterojunction with enhanced visible light photocatalytic activity for hydrogen evolution.

Construction of heterojunction is an effective strategy to conquer the severe charge carrier recombination limitation of single component g-C3N4 photocatalyst. In the present work, novel heterojunctions composed of g-C3N4 nanosheets and Sr0.4H1.2Nb2O6·H2O nanooctahedrons were constructed via a simple hydrothermal method. The as-prepared Sr0.4H1.2Nb2O6·H2O/g-C3N4 (HSN/CN) heterojunction showed high photocatalytic activity in the water splitting reactions. Specially, it is found that the developed 20 wt%-HSN/CN heterojunction shows high water splitting activity with H2 evolution rate up to 469.4 μmol g-1, which was much higher than that of bare CN. This enhanced photocatalytic activity for H2 evolution can be mainly attributed to the matched energy level and heterojunction structure which could improve the photo-generated charge carriers separation and transfer. This work implies that construction of heterojunctions with a wide band gap semiconductor is a feasible strategy for enhancement of photocatalytic activity of CN materials.