Construction of a 2D layered BiVO4/zinc porphyrin (ZnTCPP) S-scheme heterostructure boosting photocatalytic N2 oxidation performance

Abstract

Nitric acid is considered to be an important chemical raw material; however, the traditional production of nitric acid is an energy-intensive process. Photocatalysis provides an ideal way to oxidize nitrogen to nitrate through a green process, but still faces the limitations of low visible light utilization and rapid carrier compounding. Herein, a unique S-scheme heterojunction of a 2D/2D BiVO₄/metalloporphyrin (ZnTCPP) layered composite with high visible-light photocatalytic N₂ oxidation activity is reported. The nitrate yield of the optimal sample (BZ-20) reaches 4.72 mg g⁻¹ h⁻¹ and the apparent quantum efficiency reaches 0.80% at 420 nm, which represents the highest photocatalytic activity for nitrate production so far. Experimental and density functional theory calculation results indicate that a unique S-scheme charge transfer path can be formed at the BiVO₄/ZnTCPP interfaces to ensure superior separation and redox ability of photogenerated electrons and holes, resulting in high photocatalytic performance. This work provides a new insight into metalloporphyrin-based photocatalysts for efficient N₂ photofixation driven by the S-scheme charge transfer route.