Novel g-C3N4/C/Fe2O3 Composite for Efficient Photocatalytic Reduction of Aqueous Cr(VI) under Light Irradiation

Research on the rational design of photocatalysts for efficient hexavalent chromium (Cr(VI)) reduction from Cr(VI)-containing wastewater has attracted widespread attention. In this paper, a novel g-C3N4/C/Fe2O3 photocatalyst was successfully synthesized by anchoring g-C3N4 nanosheets onto C/Fe2O3 that was prepared using collagen fiber as the biochar resource following the Fe tanning mechanism to reduce Cr(VI) under artificial solar irradiation. Under the same conditions, the as-prepared g-C3N4/C/Fe2O3 photocatalyst exhibited higher Cr(VI) reduction efficiency than g-C3N4, and the Cr(VI) reduction efficiency increased as Fe content in the g-C3N4/C/Fe2O3 photocatalyst increased. The enhanced photocatalytic performance was primarily ascribed to the formation of an indirect Z-scheme heterojunction between C/Fe2O3 and g-C3N4, which improved the separation efficiency of the photogenerated charge carrier. Furthermore, radical trapping indicated that photoinduced electrons (e–) were the main factor for Cr(VI) reduction. This work provides guidance for high value-added utilization of collagen fiber in constructing efficient light-driven photocatalysts and practical Cr(VI) removal from wastewater.