Construction of a N−Mo−O bond bridged MoO2/Mo-doped g-C3N4 Schottky heterojunction composite with enhanced interfacial compatibility for efficient photocatalytic degradation of tetracycline

To improve the photocatalytic performance of g-C3N4 (CN), mechanical activation (MA) treatment of precursor followed by calcination was developed to construct a N−Mo−O bond bridged MoO2/Mo-doped CN (MA-MoO2/Mo-CN) Schottky heterojunction composite, which was used as a visible light-driven photocatalyst for degrading tetracycline (TC). The as-prepared MA-MoO2/Mo-CN with strong interfacial interaction showed excellent photocatalytic performance and structural stability, with 92.3% of TC degradation efficiency within 90 min and maintaining over 90% of degradation efficiency after five consecutive cycles. The enhanced photocatalytic performance can be ascribed to that MA treatment induced the improvement of surface area and the formation of N vacancies and N−Mo−O bonds, which served as a bridge to connect Mo-CN and MoO2 for constructing a Schottky barrier. These provided more reactive sites and effectively enhanced migration efficiency of interface electrons, separation efficiency of photogenerated carriers, and light absorption capacity. In addition, the mechanism of photocatalytic degradation of TC and its possible degradation pathway were investigated. This research provides an environmentally friendly and feasible method for producing highly active precious metal-free photocatalysts with excellent migration and separation efficiency of photoexcited charge carriers.