Polymer nanofilm-coated catalysis: An approach for enhancing water-resistance of Co-Fe oxide nano-catalysts under moisture-rich condition

Abstract

Water-induced deactivation of the oxides catalysts (especially for the Co3O4-based catalysts) is a challenging problem. For this reason, highly effective, long-term stable, moisture-resistant polymer nanofilm-coated FeaCobOx catalysts were synthesized by a solid-phase method mediated with oxalic acid (OA)/ethlyene glycol (EG) for low-temperature CO oxidation. The effects of the Fe, OA and EG amounts and calcination temperature on the physicochemical and catalytic properties of the FeaCobOx catalysts were investigated by various characterization techniques. The results demonstrate that the FeaCobOx catalysts are structurally mesoporous, and nanostructured FeaCobOx and polymer nanofilm coating play major roles on their high catalytic activity and stability. The nanofilm-coated Fe3Co16Ox nanoparticles prepared under an optimized synthetic condition and calcined at 250°C possesses higher surface area (134m2/g), Co3+/Co2+ ratio (1.89) and oxygen vacancy (20.5%), and thus exhibits the excellent catalytic performance for CO oxidation, such as, T50 of −114°C under normal moisture (3–10ppm) and T50 of 47°C under moisture-rich (∼0.6vol.%) conditions. Remarkably, compared with the published results, its much-improved long-term catalytic stability (>1month) can be observed even at a very high moisture level (3.1vol.%) and relatively low temperature (90°C). The deactivation of the catalyst at lower temperature resulted from accumulated water and carbonates on the catalyst surface can also be substantially minimized, through the water vapor-resistant with the help of gas-permeable polymer nanofilm coating.