Is single-atom catalyzed peroxymonosulfate activation better? Coupling with metal oxide may be better

ABSTRACT Single-atom catalysts (SACs) as a new class of peroxymonosulfate (PMS) activator are still limited by the low metal loading and activity. Here, we introduce a new strategy of interfacial coupling SACs with metal oxides to fine-tune the active single-atom sites and improve the atomic utilization efficiency. Taking Co 3 O 4 @Co 1 /C 3 N 5 as a case, the formation of heterostructures enhanced the activity of outer-sphere SACs for PMS activation , further upgrading the kinetics of diclofenac sodium degradation. The degradation rate of the composite increases by up to approximately 28.0 and 2.5 times compared to Co 3 O 4 and Co 1 /C 3 N 5 , respectively. The Co 1 –O (Co 3 O 4 ) and Co–N (Co 1 /C 3 N 5 ) bonds between Co 1 /C 3 N 5 and Co 3 O 4 make a tightly coupled interface for charge migration, which synergically optimizes the PMS adsorption configuration toward reactive species generation with lower activation energy . Co 3 O 4 @Co 1 /C 3 N 5 also exhibits excellent reusability and can be employed in broad application scenarios.