Revealing the excellent catalytic combustion ability of Cu1.5Mn1.5O4 (222) crystal facet with octahedrally coordinated Mn(Ⅳ)O6 site

In this study, Cu 1.5 Mn 1.5 O 4 spinel with Mn(Ⅳ)O 6 coordination was synthesized by evaporation and combustion method. CuMn-500-1 catalyst was obtained by acid etching, which significantly promotes the catalytic oxidation of toluene (lowering ≈ 30℃ regarding T 100 ). Characterization results demonstrate that the enhanced performance can be attributed to the increased exposure of (222) crystal facet of a more rod-like Cu 1.5 Mn 1.5 O 4 spinel, independent of surface area and oxygen vacancy (which remained almost unchanged). In addition, the rate-determining steps were proved to be the ring-opening reaction of phenol by in-situ DRIFTS experiment. Density functional theory calculation further shows that the Mn(Ⅳ)O₆ site exhibits stronger capacity for toluene adsorption. In addition, the main cause underlying the enhanced performance of CuMn-500-1 is further corroborated: specifically, the (222) crystal surface demonstrates stronger catalytic performance compared to other crystal faces. This strategy provides a new method in enhancing the VOCs removal efficiency of catalyst.