Ternary graphitic carbon nitride/red phosphorus/molybdenum disulfide heterostructure: An efficient and low cost photocatalyst for visible-light-driven H2 evolution from water

Abstract

Graphitic carbon nitride (g-C3N4) is a low cost photocatalyst for visible-light-driven H2 evolution from water. However, it faces the issue of rapid charge recombination that significantly suppresses the photocatalytic activity. Herein, we report a novel strategy in which low cost red phosphorus (RP) photocatalyst and molybdenum disulfide (MoS2) cocatalyst are co-introduced to accelerate photogenerated charge separation and transfer of g-C3N4. The g-C3N4/RP/MoS2 ternary composites are prepared by a step-by-step deposition method on g-C3N4 surface. Under the irradiation of visible light, the peak H2 evolution rate of 257.9 μmol g−1 h−1 is obtained when the loaded amounts of RP and MoS2 are 3.18 and 0.52 wt% (g-C3N4/RP-3.18/MoS2-0.52), respectively. When compared with pure g-C3N4 and g-C3N4/RP-3.18 in terms of H2 evolution activity, g-C3N4/RP-3.18/MoS2-0.52 demonstrates approximately 859.7 and 4.4 times, respectively. The loading of RP inhibits charge recombination of g-C3N4 due to the matched energy band position, the photoexcitation of RP itself increases total charge amount, as well as the presence of MoS2 accelerates charge separation and transfer of g-C3N4/RP-3.18. These cooperative effects make g-C3N4/RP-3.18/MoS2-0.52 exhibit an enhanced activity. We believe that this study is meaningful for building novel efficient and low cost g-C3N4 based heterostructure photocatalysts.