Targeting active sites nickel-porphyrin over BiOBr nanosheets with excellent charge separation for accelerated photoreduction reactions

The energy crisis and environmental pollution severely constrained the sustainable development of society. Herein, nickel-porphyrin active sites have been integrated over BiOBr nanosheets for enhanced photocatalytic CO₂ reduction and Cr(VI) removal. The CO generation rate of optimized NiTMCPP/BiOBr-2 photocatalyst is 14.14 μmol g⁻¹ under irradiation for 5 h, which is around 2 times compared with BiOBr. Meanwhile, Cr(VI) removal efficiency over NiTMCPP/BiOBr-2 is 97.72 % under visible light irradiation for 40 min, which shows enhanced photoreduction ability compared with BiOBr (77.31 %). Numerous experimental results indicate that the improved photocatalytic activity for NiTMCPP/BiOBr-2 is mainly owing to the enhanced transport efficiency of photoinduced carriers after the loading of nickel-porphyrin. Especially, the central Ni²⁺ active site of porphyrin can accept excitation electrons, thus enhancing photoreduction performance. Furthermore, the mechanisms for photocatalytic CO₂ and Cr(VI) reduction were further discussed through in-situ FT-IR and capture experiments. This work gives a promising way to design hybrid photocatalysts for energy conversion and environmental treatment. © 2024 Elsevier B.V.