Hydrothermal temperature-regulated interface effects in Ce@Mn core-shell catalysts for efficient formaldehyde removal

In this paper, a series of Ce@Mn core-shell catalysts were synthesized via a two-step hydrothermal method. Hydrothermal temperature significantly influenced the structure formation of catalysts. The Ce@Mn-150 catalyst, synthesized at 150 °C exhibited a well-defined core-shell structure. Moreover, it converted approximately 35 % of HCHO into CO 2 and H 2 O at ambient temperature, and achieved 90 % conversion of HCHO at 90 °C. Through structural characterization of the catalysts, distinct morphological differences were observed across all samples. The Ce@Mn-150 catalyst, which demonstrated the optimal catalytic activity, exhibited the most complete core-shell structure. The formation of the core-shell structure promoted the generation of Ce-Mn interfacial effects, which in turn modulated the interactions between Ce and Mn species . Elemental valence state characterization revealed that the well-defined core-shell structure facilitated the generation of Mn 3+ and Ce 3+ species, along with enhanced concentrations of surface-adsorbed oxygen (O ads ) and oxygen vacancies (O v ), which collectively enhanced HCHO adsorption and activation. H 2 -TPR results indicated that the core-shell structure enhanced the low-temperature reducibility of the catalyst and preserved abundant oxygen vacancies. This study revealed the influence of core-shell structures and intermetallic interactions at the core-shell interface on the catalytic performance of the catalyst, providing insights for designing efficient non-noble metal catalysts for HCHO removal.