Dual synergetic effects in MoS2/pyridine-modified g-C3N4 composite for highly active and stable photocatalytic hydrogen evolution under visible light

Abstract

Composite photocatalysts with nanoflower-structured MoS2 grown on pyridine-modified graphitic carbon nitride (g-C3N4) have been synthesized through a facile in situ solvothermal approach. These composites demonstrate greatly enhanced response to visible light, and consequently remarkably enhanced hydrogen evolution performance by photocatalytic water splitting. The addition of 2,5-dibromopyridine during the formation process of g-C3N4 can not only enhance the photocatalytic activity but also the durability of the photocatalysts. The MoS2 content and the ratio between 2,5-dibromopyridine and g-C3N4 in these composites can be well tuned to obtain the optimized photocatalytic activity with a peak H2 production rate of 25μmolh−1 on 50mg photocatalyst without adding any noble metal under visible light irradiation at 283K. A dual synergetic mechanism in MoS2/pyridine-modified g-C3N4 composite, which is featured with significantly promoted separation of photo-generated carriers and stability of S2− and/or S22− in the composites under visible light irradiation, has been proposed to account for the distinguished hydrogen evolution activity and stability of these composite photocatalysts.