Boosting ethyl acetate low-temperature deep oxidation by tuning the initial status of Ag over MnO₂: Intrinsic role of Ag nanoparticles and ions

Promoting activity while inhibiting hazardous byproduct formation remains a great challenge in oxygenated volatile organic compounds (OVOCs) purification. Here, we found that the low-temperature oxidation of ethyl acetate (EA) and the generation rate of CO₂ were enhanced by controlling the initial Ag precursor (ions vs. nanoparticles) to engineer catalysts with distinct active site configurations. The reaction rate and TOF_Ag of Ag nanoparticles/310MnO₂ (Ag-NP/310MnO₂) are 4.3 and 4.1 times higher, respectively, than those of Ag ions/310MnO₂ (Ag-IS/310MnO₂) at 150 °C. And Ag-NP/310MnO₂ further shows a 1.9-fold higher CO₂ selectivity compared to that of Ag-IS/310MnO₂. The adsorption ability of EA is much stronger than that of O₂ at Ag site, while the opposite trend is observed at oxygen vacancy. The synergy between Ag site (EA adsorption) and oxygen vacancy (O₂ dissociation) in Ag-NP/310MnO₂ accelerates O₂ activation and subsequent EA oxidation. Moreover, abundant active oxygen species (*O) promote the rate-limiting step of acetic acid decomposition, contributing to superior low-temperature CO₂ selectivity. However, due to the fierce competition from EA, limited O₂ is adsorbed at Ag site-occupied oxygen vacancy, which is difficult to dissociate especially at low temperature, leading to inferior activity of Ag-IS/310MnO₂. This work provides a vital scientific basis for enhancing the low-temperature deep oxidation of OVOCs, showcasing remarkable environmental significance.