Carbonate-enhanced catalytic activity and stability of Co3O4 nanowires for 1O2-driven bisphenol A degradation via peroxymonosulfate activation: Critical roles of electron and proton acceptors

• CO 3 2− enhanced catalytic activity and stability of Co 3 O 4 for PMS activation. • Faster catalysis occurred when solution pH exceeded but approached pH PZC of Co 3 O 4 . • The dominated reactive species switched from •OH/SO 4 •− to 1 O 2 after adding CO 3 2- . • CO 3 2− drove the catalytically active center migrating from Co(II) to Co(III). • Co(III) and CO 3 2− /OH - were electron and proton acceptors to promote 1 O 2 evolution. Transition-metal catalysts (TMCs) for peroxymonosulfate (PMS) activation suffer from low stability (i.e. severe metal leakage and poor reusability) when maintaining high activity in water decontamination. An innovative carbonate (CO 3 2− )-mediated method to synchronously enhance the catalytic activity and stability of TMCs was developed herein. In a model PMS/Co 3 O 4 nanowire system for bisphenol A (BPA) degradation, the first-order kinetic constant and total organic carbon removal ratio were increased by 202.27% and 71.32% upon adding CO 3 2− , respectively. Meanwhile, the cobalt release amount was significantly reduced from 4.90 to 0.03 mg/L, and the number of reuse with high efficiency (>90% of BPA removal within 10 min) was augmented from 1 to 3 times. The CO 3 2− buffered pH decline to repress metal leakage, and promoted Co(III) reduction into Co(II) to avoid the over-oxidation of catalyst. Under the driving of CO 3 2− , the dominated reactive species were switched from •OH/SO 4 •- to 1 O 2 accompanying the migration of catalytic center from Co(II) to Co(III). The Co(III) and CO 3 2− /OH - acted as electron and proton acceptors, respectively, to accelerate PMS decomposition into SO 5 •- and subsequent generation of vast 1 O 2 . This work proposes a green way to construct novel 1 O 2 -based catalytic systems with excellent activity and stability for pollution remediation.