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 (KRhB and KCr) 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 •O2– 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.