Tailoring Oxygen Vacancies in Co3o4 Yolk-Shell Nanospheres Via for Boosted Peroxymonosulfate Activation: Single-Electron Transfer and High-Valent Co-Oxo Species-Dominated Non-Radical Pathways Publisher



Khiem TC¹ ; Huy NN^{2, 3} ; Kwon E⁴ ; Waclawek S⁵ ; Ebrahimi A⁶ ; Oh WD⁷ ; Ghotekar S⁸ ; Tsang YF⁹ ; Chen WH^{10, 11, 12} ; Lin KYA^{1, 13} Show Affiliations
Source: Chemical Engineering Journal Published:2023

Abstract

As Co3O4 represents a promising material for peroxymonosulfate (PMS) activation, a yolk-shell-structured nanosphere, Co3O4-x-0.20, is developed here for maximizing its catalytic activity by governing electronic structures via tailoring oxygen vacancies (OV) of Co3O4. This OV-tailored Co3O4 enables single-electron transfer and generates high-valent cobalt-oxo species (Co(IV) = O) to achieve the fastest phenol degradation. The single-electron transfer is unraveled by an electron donation of Co atoms near OV to O2 to form O2[rad]− followed by O2 evolution after 1O2 and the charge balance maintained by an electron acquisition from phenol by the electron-deficient Co atoms. Meanwhile, the generation of Co(IV) = O by the cleavage of the S[sbnd]O bond in the Co(II)-O-SO3-OH complex accepts electrons from phenol to turn back to Co(II) and Co(III), causing phenol oxidation. These results demonstrate the pre-eminence of Co3O4-x-0.20 over the reported catalysts for phenol degradation and also offer insights into the mechanism of OV triggering electron donation and enhancing Co(IV) = O generation. © 2023 Elsevier B.V.