Hydroxyl-Induced\nElectronic Structure and Electron\nTransfer for Improved N<sub>2</sub>O Decomposition Activity of Co<sub>3</sub>O<sub>4</sub>

Hydroxyl groups (−OH) were loaded on the surface\nof Co<sub>3</sub>O<sub>4</sub> through hydrothermal treatment, which\nenhanced\nthe electron transfer process at the gas–solid interface and\nthe N<sub>2</sub>O decomposition performance. Hydrothermal treatment\ndoes not substantially alter the crystal structure or oxygen vacancy\ncontent of the Co<sub>3</sub>O<sub>4</sub> catalyst, while it slightly\nsuppresses the BET surface area and reducibility. These factors do\nnot primarily contribute to the enhanced N<sub>2</sub>O decomposition\nactivity of Co<sub>3</sub>O<sub>4</sub>. The −OH content peaks\nat 8 h of hydrothermal treatment, correlating with the highest catalytic\nactivity. Electronic structure analysis reveals that the −OH\ngroups raise the d-band center and narrow the band gap, thereby facilitating\nN<sub>2</sub>O adsorption and electron transfer. DFT simulations support\nthese findings, indicating that −OH groups enhance electron\ntransfer from Co to N<sub>2</sub>O, promoting N–O bond cleavage\nand lowering the activation barrier. This work provides an in-depth\nexploration of the mechanism by which hydroxyl groups facilitate electron\ntransfer processes, offering fundamental insights into catalytic science\nand providing guidance for new catalyst design.