Semi-Covalent Interaction-Induced Electron Transfer in Single-Atom Alloy Catalysts Enhance Singlet Oxygen Generation...

Selectively producing singlet oxygen (¹O₂) through peroxymonosulfate (PMS) activation holds significant promise for sustainable water pollution control. Single-atom alloy catalysts (SAACs) possess unique active sites and electronic structures, demonstrating strong potential to enhance ¹O₂ generation. However, the effect of single atom metal insertion on the electronic structures of SAACs and their catalytic performance of activated PMS remains unclear. Herein, a series of SAACs (M-Co₃O₄/C), in which metal atoms M (M = Mn, Fe, Cu, or Ni) are atomically dispersed on carbon-supported hollow dodecahedral Co₃O₄ are synthesized. These catalysts exhibit exceptional catalytic activity in mediating PMS self-decomposition to selectively generate ¹O₂ for the degradation of bisphenol A (BPA), with the k_obs of the Cu-Co₃O₄/C/PMS (2.90 min^-1) being 4.32 times higher than that of Co₃O₄/C. Experimental and computational studies reveal that the remarkable catalytic activity of M-Co₃O₄/C/PMS systems originates from the semi-covalent coupling between M and Co, which induces electron transfer from Co to the M site. This electron redistribution enhances PMS adsorption at the electron-rich M site and lowers the reaction energy barrier for efficient pollutant degradation. This study offers atomic-scale insights into PMS activation mechanisms, providing guidance for designing advanced SAACs to enhance pollutant degradation efficiency.