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

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.