Enhanced PMS activation by surface electronic reconstruction at Co3O4/ZnO heterointerface: Performance and mechanism

Peroxymonosulfate (PMS) activation is regarded as a powerful method for eliminating refractory organic pollutants. A PMS catalyst with a rapid electron-transfer capability is vital for the generation of active species. Herein, an efficient Co3O4/ZnO catalyst with abundant Co3O4-ZnO heterointerface is synthesized by calcining Zn3[Co(CN6)]2 prussian blue analogues. Such a heterointerface can induce electron redistribution due to different work function between Co3O4 and ZnO, as confirmed by XPS characterization. Owing to the electron redistribution at Co3O4-ZnO heterointerface, a faster electron-transfer between catalyst and PMS is achieved, as proved by electrochemical studies. A series of controlled experiments, characterization and density functional theory calculation suggest that the fast electron transfer benefits from the enhanced electron-donating ability of Co(II) and the increased active sites (oxygen vacancy). Therefore, Co3O4/ZnO-3 shows superior catalytic activity toward PMS than Co3O4. The pseudo-first-order kinetic constant for phenol degradation by Co3O4/ZnO-3 (0.31 min–1) is 4 times higher than that of Co3O4. Besides, other refractory organic pollutants including bisphenol A, sulfamethoxazole, ibuprofenand and rhodamine B could also be degraded effectively by Co3O4/ZnO-3 system. This study highlights how the interface design can optimize the electronic structure for enhanced catalytic activity and provides a new strategy to develop efficient PMS catalyst.