Double-Confined Ultrafine Cobalt Clusters for Efficient Peroxide Activation

[Image: see text] The construction of highly active catalysts presents great prospects, while it is a challenge for peroxide activation in advanced oxidation processes (AOPs). Herein, we facilely developed ultrafine Co clusters confined in mesoporous silica nanospheres containing N-doped carbon (NC) dots (termed as Co/NC@mSiO(2)) via a double-confinement strategy. Compared with the unconfined counterpart, Co/NC@mSiO(2) exhibited unprecedented catalytic activity and durability for removal of various organic pollutants even in extremely acidic and alkaline environments (pH from 2 to 11) with very low Co ion leaching. Experiments and density functional theory (DFT) calculations proved that Co/NC@mSiO(2) possessed strong peroxymonosulphate (PMS) adsorption and charge transfer capability, enabling the efficient O–O bond dissociation of PMS to HO(•) and SO(4)(•–) radicals. The strong interaction between Co clusters and mSiO(2) containing NC dots contributed to excellent pollutant degradation performances by optimizing the electronic structures of Co clusters. This work represents a fundamental breakthrough in the design and understanding of the double-confined catalysts for peroxide activation.