Highly active Mn-V_O-Co sites by cobalt doping on cryptomethane for enhanced catalytic decomposition of N₂O

Direct catalytic decomposition has shown great promise in controlling the greenhouse gas N₂O. Herein, we synthesize a series of cobalt-doped cryptomethane (OMS-2) catalysts for N₂O catalytic decomposition by a mild one-step sol-gel method. The Co_0.1-OMS-2 exhibits superior catalytic performance with 90% N₂O conversion at 398 °C, which is attributed to the formation of the Mn-V_O-Co structure served as active sites. The increased electron density on oxygen vacancies promotes the electron transfer between oxygen vacancies and N₂O molecules, in turn facilitating the adsorption and activation of N₂O. Moreover, Co doping reduces the formation energy of oxygen vacancies. However, excessive Co doping results in the decrease of highly active Mn-V_O-Co sites and the formation of Co₃O₄, which makes Co_0.3-OMS-2 exhibit poor catalytic activity. The DFT calculation illustrates that Langmuir-Hinshelwood is the primary reaction mechanism over Co_0.1-OMS-2. This study broadens the materials applicable for the catalytic decomposition of N₂O, offering an effective approach to modulate the electronic structure at oxygen vacancies.