Effective enhancement of electron migration and photocatalytic performance of nitrogen-rich carbon nitride by constructing fungal carbon dot/molybdenum disulfide cocatalytic system

To find a cocatalyst that can replace noble metals, fungal carbon dot (CD) modified molybdenum disulfide (MoS₂) cocatalyst system was designed. The composites were prepared by hydrothermal and calcination methods with different ratios of CDs, MoS₂ and nitrogen-rich carbon nitride (p-C₃N₅). p-C₃N₅ has excellent electronic properties, and MoS₂ modified by CDs (D-MoS₂) can significantly enhance the photocatalytic performance of p-C₃N₅ by improving the photogenerated electron migration efficiency. The experiments showed that the developed CDs/MoS₂/C₃N₅ composites exhibited excellent performance in both photocatalytic hydrogen (H₂) evolution and methylene blue (MB) degradation, with CMSCN5 (D-MoS₂ with 5% mass fraction) showing the best photocatalytic activity. The corresponding H₂ evolution rate of CMSCN5 was 444 μmol g^-1h^-1 and 1.45 times higher than that of unmodified p-C₃N₅, by 120 min, the removal rate of MB was up to 93.51%. The 5 cycle tests showed that CMSCN5 had great stability. The high charge mobility and high density of H₂ evolution active sites of MoS₂ nanosheets, together with the electron storage and transfer properties of CDs can obviously improve electron migration and reduce the photogenerated carrier recombination on the p-C₃N₅ surface. The design and preparation of such composites offer broad prospects for the development of photocatalytic systems with noble metal-free cocatalysts.