Role of holes in microwave-induced catalyst Co3O4 for efficient high-concentration tetracycline degradation

Abstract

Microwave-induced catalytic is a potential organic wastewater treatment technology. In this work, a new type of microwave-induced catalyst Co3O4 was synthesized and used to remove tetracycline (TC) under microwave (MW). The results have shown that the spherical Co3O4 exhibited impressively high catalytic activity with 100 mg·L-1 TC degradation efficiency of 100 % under MW at 800 W within 30 min. Importantly, Co3O4 catalyst displayed excellent stability with the degradation efficiency. The electron-hole pairs were generated under MW in the presence of Co3O4, which was confirmed by electron paramagnetic resonance and active species scavenging experiments. Part of the electrons (e-) was captured by oxygen vacancies produced under MW, and holes (h+) acted as the main active species for participating in the degradation process of TC. This work indicated the effect of MW for the separation of electrons and holes and provides new ideas for the mechanism of microwave-induced catalytic degradation.