Hydroxyl-Induced Electronic Structure and Electron Transfer for Improved N₂O Decomposition Activity of Co₃O₄

Hydroxyl groups (−OH) were loaded on the surface of Co3O4 through hydrothermal treatment, which enhanced the electron transfer process at the gas–solid interface and the N2O decomposition performance. Hydrothermal treatment does not substantially alter the crystal structure or oxygen vacancy content of the Co3O4 catalyst, while it slightly suppresses the BET surface area and reducibility. These factors do not primarily contribute to the enhanced N2O decomposition activity of Co3O4. The −OH content peaks at 8 h of hydrothermal treatment, correlating with the highest catalytic activity. Electronic structure analysis reveals that the −OH groups raise the d-band center and narrow the band gap, thereby facilitating N2O adsorption and electron transfer. DFT simulations support these findings, indicating that −OH groups enhance electron transfer from Co to N2O, promoting N–O bond cleavage and lowering the activation barrier. This work provides an in-depth exploration of the mechanism by which hydroxyl groups facilitate electron transfer processes, offering fundamental insights into catalytic science and providing guidance for new catalyst design.