Self-Assembly of Ce/Cu-MOFs on Attapulgite for Enhanced Low-Temperature CO Oxidation: Interfacial Engineering and Reaction Mechanism

Attapulgite (ATP) is a natural, low-cost material with a stable framework, abundant pore channels, and surface functional groups, making it an ideal catalytic support. Still, single-component ATP has a limited CO adsorption capacity. Herein, ATP modified with organic ligands was used to anchor the highly dispersed Me (Me=Ce/Cu) metallic species through a self-assembly strategy. We discovered that the strong interfacial interaction between the surface functional groups of ATP and Me-MOF (Me=Ce/Cu) enhanced the dispersion and stability of active Cu and Ce species. Accordingly, four catalysts were prepared, including ATP@CeCuOx-M, Ce-ATP@CuOx-M, Cu-ATP@CeOx-M through a self-assembly strategy, and ATP@CeCuOx through impregnation synthesis. The results of activity evaluation indicated that ATP@CeCuOx-M catalyst exhibited an excellent low-temperature catalytic activity (T90=140 oC) and water resistance (△COCon=31.84%) for the catalytic oxidation of CO. Multiple characterizations confirmed that the excellent low-temperature redox, the surface rich Ce3+ and Cu0/Cu+ species, and adsorbed oxygen species played the key factors in enhancing the catalytic activity of CO. In situ infrared spectroscopic analysis of ATP@CeCuOx-M catalyst indicated that there was no significant difference in the reaction pathways under dry and humid conditions, and the introduction of water could decrease the adsorption temperature of reaction intermediates. This study provided a feasible approach for the design and preparation of highly efficient CO oxidation catalysts based on natural ATP.