Synergistic Mechanism of Peroxymonosulfate Activation and Photoexcitation on the Pyrolytic Bimetallic Metal–Organic Framework for Enhanced Charge Transfer

Photocatalysis based on peroxymonosulfate (PMS) activation has shown great potential in environmental remediation, and photocatalysts containing transition-metal active sites can efficiently activate PMS. However, under-utilizing metal active sites results in limiting catalytic efficiency. To overcome this problem, this work developed bimetallic metal-organic framework-derived metal oxide-loaded nitrogen-doped carbon Z-scheme heterojunction photocatalysts to achieve PMS activation synergistic photoexcitation by an interface electric field. Benefiting from multiple synergistic reaction pathways, the tetracycline degradation rate was significantly accelerated. Experiments and density functional theory calculations supported the hypothesis that the bimetallic oxide activated the adsorption energies of PMS through electron rearrangement, contributing to the generation of reactive oxygen species. The metastable PMS adsorbed on the surface of the photocatalysts can modify the surface potential, further improving charge carrier separation. Meanwhile, the "contaminant-metal-oxidant" coordination mode at the metal center facilitates O-O bond of PMS cleavage, driving a dominant 1O2 generation via nonradical electron-transfer pathways. This work deepens the knowledge of design strategies for efficient photocatalysis in enhancing heterogeneous catalysis water purification processes.