Recyclable Nanoscale Zero Valent Iron Doped g‑C₃N₄/MoS₂ for Efficient Photocatalysis of RhB and Cr(VI) Driven by Visible Light

Photocatalytic materials for environmental remediation of organic pollution and heavy metals require not only a strong visible light response and high photocatalytic performance, but also the regeneration and reuse of catalysts. In this work, a ternary hybrid structure material of a nanoscale zero valent iron (Fe⁰) doped g-C₃N₄/MoS₂ layered structure (GCNFM) was synthesized by a facile strategy. Compared with the pure GCN, GCNM, and Fe-GCN, the photodegradation efficiency of the GCNFM toward the RhB and Cr­(VI) under visible light is considerably enhanced, to 98.2% for RhB and 91.4% for Cr­(VI), respectively. In addition, the reaction rate constants (K_RhB and K_Cr) of GCNFM are much higher than those of GCN, GCNM, and Fe-GCN, which is attributed to the fact that Fe⁰ and MoS₂ composited with GCNM promote the separation of photogenerated electron–hole pairs. Moreover, with the loading of MoS₂ and/or Fe⁰, the holes could displace the ^•O^2– as the main reactive oxygen species in GCN. GCNFM maintains an efficient degradation ability to both RhB and Cr­(VI) after several cycles, in spite of the fact that normally Fe⁰ will be consumed and deactivated with the reduction proceeding as previously reported. This suggests that the photogenerated electrons, in response, can reduce the Fe­(III)/Fe­(II) to Fe⁰, inducing regeneration and reuse of Fe⁰. We anticipate this work can provide a good example for the design of efficient, visible light driven, and recyclable photocatalysts for environmental remediation of both organic pollution and heavy metals.