Oxygen Vacancies Engineering of Co3O4 to Modulate the Adjacent Environment: Boosted Singlet Oxygen Generation in Peroxymonosulfate-Mediated 2-Chlorophenol Degradation

Peroxymonosulfate-based advanced oxidation processes are promising for removing organic pollutants but precisely generating singlet oxygen ( 1 O 2 ) as nonradical reactive oxygen species is difficult. Herein, a porous Co 3 O 4 nanosheet was synthesized and further tailored by the bulk doping of Mn and the surface loading of Ru. The abundant oxygen vacancies (O v ) could be created by the Mn doping and then facilitated the precise anchoring of Ru, which in turn contributed to the construction of the adjacent heteronuclear diatomic adsorbed sites (Co–O v –Ru). In the base MnCoO x /peroxymonosulfate (PMS) system, the electron transfer occurred between the ≡Co(III)–(O)OSO 3 – complex and free HSO 5 – to produce the O 2 •– and subsequently the adjacent O 2 •– trapped on the O v disproportionates into 1 O 2, whereas the anchoring of Ru occupied the O v and high-selectively boosted the self-combined generation of 1 O 2 through the heteronuclear diatomic-adsorbed PMS (SO 5 •– –Co–O v –Ru–SO 5 •– ). The optimized Ru/MnCoO x demonstrated wide pH adaptability, high efficiency, and salinity tolerance for the degradation of 2-chlorophenol, and it removes over 99% of contaminants in complex water matrices even after 36 h in fixed-bed operation. This work provided a new protocol for PMS activation through a distinctively structured and easily scaled Co 3 O 4 -based catalyst and contributed to understand the tuning generation of singlet oxygen and guide the design of metal oxide catalysts.