Construction of a BiVO4/VS-MoS2 S-scheme heterojunction for efficient photocatalytic nitrogen fixation

Abstract

Photocatalytic nitrogen (N₂) reduction to ammonia (NH₃), adopting H₂O as the electron source, suffers from low efficiency owing to the sluggish kinetics of N₂ reduction and the requirement of a substantial thermodynamic driving force. Herein, we present a straightforward approach for the construction of an S-scheme heterojunction of BiVO₄/V_S-MoS₂ to successfully achieve photocatalytic N₂ fixation, which is manufactured by coupling an N₂-activation component (V_S-MoS₂ nanosheet) and water-oxidation module (BiVO₄ nanocrystal) through electrostatic self-assembly. The V_S-MoS₂ nanosheet, enriched with sulfur vacancies, plays a pivotal role in facilitating N₂ adsorption and activation. Additionally, the construction of the S-scheme heterojunction enhances the driving force for water oxidation and improves charge separation. Under simulated sunlight irradiation (100 mW cm⁻²), BiVO₄/V_S-MoS₂ exhibits efficient photocatalytic N₂ reduction activity with H₂O as the proton source, yielding NH₃ at a rate of 132.8 μmol g⁻¹ h⁻¹, nearly 7 times higher than that of pure V_S-MoS₂. This study serves as a noteworthy example of efficient N₂ reduction to NH₃ under mild conditions.