Simple Hydrothermal Synthesis of g-C3N4/Ni9S8 Composites for Efficient Photocatalytic H2 EvolutionSimple Hydrothermal Synthesis of g-C3N4/Ni9S8 Composites for Efficient Photocatalytic H2 Evolution

Abstract The prompt recombination between photogenerated electrons and holes is the common problem for improving the hydrogen evolution properties of a photocatalyst, which could be solved greatly by composite co-catalysis. Herein, a simple hydrothermal reaction was utilized to prepare g-C3N4/Ni9S8 composite photocatalysts. Through electroless nickel plating, Ni9S8 nanostructure was homogeneously grown onto the g-C3N4 surface by using sodium hypophosphite as reducing agent. With the optimum amount of Ni9S8, the acquired g-C3N4/Ni9S8 composite compared with the raw g-C3N4 which has an excellent increase in hydrogen evolution rate under visible light irradiation. Its rate of hydrogen evolution measured at 7 degrees Celsius was 355.7 μmol·g-1·h-1, being 21.2 time that of raw g-C3N4. The mechanism for the hydrogen evolution reaction over the present g-C3N4/Ni9S8 composite photocatalysts was discussed in detail.