Fully Amorphous Cerium/Carbon-Doped Manganese Oxides with Tailor-Made Pore and Electronic Properties for Superior...

Metal oxides are promising for catalytic ozone (O₃) decomposition to tackle the O₃ pollution problem. However, reported metal oxides for O₃ decomposition are predominantly crystalline and often suffer from low active site exposure and easy deactivation. Here, fully amorphous Ce/C-doped Mn₂O₃ materials with tailor-made macro-mesopores and electronic properties are developed. The synthesis is enabled by forming amorphous metal-organic coordination composites between histidine and atomically mixed metal ions, which are thermally converted to hierarchically porous amorphous Mn₂O₃ due to the Ce/C doping in the Mn₂O₃ skeleton and the self-bubbling and reductive roles of histidine. They demonstrate superior activity and stability in O₃ decomposition under wide relative humidity (RH, 0-80%), capable of completely eliminating 50 ppm O₃ for >25 h at 60% RH and a high velocity of 600 L g^-1 h^-1. Spectroscopic and theoretical studies unravel the structure-performance correlation and reaction mechanism. The superior performance originates from the amorphous Mn₂O₃ providing rich Mn³⁺ sites and a high surface area for O₃ adsorption and activation, the Ce/C doping for promoting suitable electron transfer and inhibiting H₂O and O₂^2- accumulation, and the macro-mesopore structure for enhancing mass transfer and weakening H₂O adsorption and condensation.