Highly dispersed Fe-Ce mixed oxide catalysts confined in mesochannels toward low-temperature oxidation of formaldehyde

Catalytic oxidation of formaldehyde (HCHO) is regarded as a promising strategy to eliminate this indoor air pollutant. The design of a highly active and cost-effective catalyst is still pivotal to improve the performance for HCHO oxidation. Herein, we report an Fe-Ce-O solid solution catalyst supported on ordered mesoporous silica (SBA-15) prepared by simple two-step impregnation-calcination, achieving highly efficient HCHO elimination at a low temperature. This strategy brings about the formation of small solid solution nanoparticles (7-12.9 nm) with good dispersion in confined spaces. Meanwhile, the catalysts possess large surface areas (∼500 m2 g-1) and pore volumes (0.5 cm3 g-1) with a pore size of ∼7.5 nm. The results show that Fe content and calcination temperature have great effects on the generation of oxygen vacancies in the catalyst, and further on the catalytic performance. The 20% FeOx-CeOx/SBA-15-350 catalyst displays superior catalytic activity with 65% and 94.9% conversion at 30 °C and 60 °C with a low concentration of HCHO (9.8 μg L-1), respectively, comparable to that for many reported precious metal catalysts. The high ratio of Ce3+ due to the formation of an Fe-Ce-O solid solution and highly dispersed active sites by the spatial confinement is favorable for more oxygen vacancy generation, which mainly contributes to the excellent performance. This work opens up an avenue to design highly efficient non-noble metal nanocatalysts for volatile organic compound (VOC) elimination.