Fully Amorphous Cerium/Carbon-Doped Manganese Oxides with Tailor-Made Pore and Electronic Properties for Superior Catalytic Ozone Decomposition
Jiaren Wang, Junrong Wu, Xingchen Guo, Jinqiang Sun, Wei Teng, Xiaoning Wang, Winston Duo Wu, Zhangxiong Wu
Abstract
Metal oxides are promising for catalytic ozone (O 3 ) decomposition to tackle the O 3 pollution problem. However, reported metal oxides for O 3 decomposition are predominantly crystalline and often suffer from low active site exposure and easy deactivation. Here, fully amorphous Ce/C-doped Mn 2 O 3 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 Mn 2 O 3 due to the Ce/C doping in the Mn 2 O 3 skeleton and the self-bubbling and reductive roles of histidine. They demonstrate superior activity and stability in O 3 decomposition under wide relative humidity (RH, 0–80%), capable of completely eliminating 50 ppm O 3 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 Mn 2 O 3 providing rich Mn 3+ sites and a high surface area for O 3 adsorption and activation, the Ce/C doping for promoting suitable electron transfer and inhibiting H 2 O and O 2 2– accumulation, and the macro-mesopore structure for enhancing mass transfer and weakening H 2 O adsorption and condensation.