Tailoring Dual High-Valence Cu–O–Mn Active Sites to Enhance VOC Catalytic Oxidation

Advancing the catalytic oxidation of volatile organic compounds (VOCs) requires ongoingly boosting of both low-temperature activity and durability. Our strategy was to tailor suitable Cu-O-Mn coordination environments across numerous types of widely used CuMn bimetallic oxides. Unexpectedly, Cu-O-Mn sites within the CuO phase ignited greater catalytic activity toward alkanes like cyclohexane under 5.0% relative humidity, with a lower T90 at 219 °C, and excellent stability over 48 h, compared to spinel phases noted for electron transfer. Doping CuO with high-valence Mn3+ and Mn4+ prefers to generate oxygen interstitials, facilitating the formation of dual high-valence Cu-O-Mn sites. Notably, optimal Cu3Mn1 simultaneously featured high-valence states of Cu1.98+ and Mn3.22+, as evidenced by the positive correlation between catalytic activity and valence state. Dual high-valence Cu-O-Mn sites within the CuO phase bolstered reactive oxygen species mobility, oxidizability, and replenishment, as well as acid sites, facilitating the Mars-van-Krevelen redox cycles. The resulting enhancement rapidly overcame the rate-limiting step of key intermediate benzene oxidation, endowing higher and sustainable reactivity. The superior performance could be validated through the catalytic oxidation of aromatics and alkenes represented by benzene and 1,3-butadiene, respectively. This work offers insights for catalyst design and promotes the practical application of CuMn bimetallic oxides in the VOC disposal.