In situ interfacial engineering modulated adsorption and electron transfer boosting peroxymonosulfate activation for micro-contaminates degradation over CoOx nanosheet

Cobalt-based oxides have attracted extensive attention in heterogeneous catalytic peroxymonosulfate (PMS) activation towards emerging pollutants degradation, while the improvement of their catalytic performance is still a severe challenge. Herein, a CoOx ultrathin nanosheet composed of in situ interfacial Co3O4 and CoO (CoOx-Ar-350) was synthesized and employed in PMS activation for micro-contaminates removal. The catalyst shows 100 % bisphenol A (BPA) conversion within 2 min ([BPA] = 20 mg/L, [Catalyst] = 20 mg/L, [PMS] = 200 mg/L) with a remarkable reaction rate of 2.69 min−1, which is 3.84 and 2.66 times of pure Co3O4 and CoO, respectively. Characterization and theoretical calculation results indicates that the interfacial synergy between Co3O4 and CoO could modulate the adsorption behavior and enhance the electron acceptance of PMS, which boosts the breaking of O-O bonds and the generation of reactive oxygen species (ROS) and thereby the pollutant removal efficiency. The ROS quenching and capture experiments demonstrate that the enhanced OH and 1O2 play significant contribution during the degradation process. This work provides a novel in situ interfacial engineering for the development of highly efficient catalyst and reveals the activity enhancement mechanism for PMS activation.