Construction of visible-light-driven 2D/2D NiFe₂O₄/g-C₃N₄ Z-scheme heterojunction photocatalyst for effective degradation of organic pollutants and CO₂ reduction

Developing photocatalytic systems with higher redox capability, large reactive surface area and enhanced charge separation are essential both from scientific and practical perspectives. To address both environmental and energy issues, herein, using a simple solvothermal and wet-chemical method, we designed a dimensionally matched Z-scheme NiFe₂O₄/g-C₃N₄ (NFO/CN) heterojunction to realize higher charge separation as confirmed from various physiochemical and electrochemical analysis. The optimized 6NFO/CN catalyst exhibited about 5.5, and 4.4-fold higher photocatalytic activity in the degradation of 2,4-dichlorophenol (2,4-DCP) and bisphenol A (BPA) pollutants respectively, in comparison to bare g-C₃N₄ nanosheets (CN). Further, the prepared samples also displayed 8.3-fold higher photoactivity for CO₂ reduction to CO and CH₄. The exceptionally improved visible-light activities were mainly attributed to the enormously enhanced charge separation through the construction of interfacial matching heterojunction for Z-scheme charge transfer. Moreover, the degradation of pollutants was primarily attributed to the involvement of superoxide radicals (•O₂^-). Hopefully, this study will provide a deep understanding to design g-C₃N₄-based dimensionally matched Z-scheme heterojunction photocatalysts for environmental remediation and solar fuel conversion.