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

Abstract

The energy crisis and environmental pollution severely constrained the sustainable development of society. Herein, nickel-porphyrin active sites have been integrated over BiOBr for enhanced photocatalytic CO2 reduction and Cr(VI) removal. The optimized NiTMCPP/BiOBr-2 photocatalyst exhibits CO generation rate of 14.14 μmol g−1 under irradiation for 5h, 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 40min, 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 Ni-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 via in-situ FT-IR and capture experiments. This work gives a promising way to design hybrid photocatalysts for energy conversion and environmental treatment.