Double-Confined Ultrafine Cobalt Clusters for Efficient Peroxide Activation

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@mSiO2) via a double-confinement strategy. Compared with the unconfined counterpart, Co/NC@mSiO2 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@mSiO2 possessed strong peroxymonosulphate (PMS) adsorption and charge transfer capability, enabling the efficient O-O bond dissociation of PMS to HO center dot and SO4 center dot- radicals. The strong interaction between Co clusters and mSiO2 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.