CoO quantum dots anchored on P-doped carbon nitride improves peroxymonosulfate activation to degrade sulfamethoxazole

The development of highly dispersed and ultra-small size cobalt-loaded catalysts is crucial for achieving efficient and low secondary pollution in peroxymonosulfate (PMS) activation processes. Herein, a phosphorus-doped carbon nitride (PCN) loaded with CoO quantum dot catalyst (Co80-PCN) was derived from the mixture of BINAP-CoCl2 complex (BINAP = 1,1′-binaphthyl-2,2′-diphosphine) and carbon nitride (CN). Structural studies revealed that cobalt oxide quantum dots with an average diameter of 9.99 nm were evenly and securely attached to the PCN substrate. The optimal Co80-PCN/PMS system demonstrated an almost 100% degradation efficiency of sulfamethoxazole (SMX, 10 mg/L) within 15 min, with a reaction rate constant of 0.3341 min−1, which was 30.1 times higher than that of the CN/PMS system. This outstanding degradation performance could be primarily attributed to the enhanced catalytic activity of CoO quantum dots and the improved electronic structure resulting from P-doped CN. This work offers valuable insights for the future design of carbon material loaded quantum dot catalysts.