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

Water-induced deactivation of the oxides catalysts (especially for the Co 3 O 4 -based catalysts) is a challenging problem. For this reason, highly effective, long-term stable, moisture-resistant polymer nanofilm-coated Fe a Co b O x 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 Fe a Co b O x catalysts were investigated by various characterization techniques. The results demonstrate that the Fe a Co b O x catalysts are structurally mesoporous, and nanostructured Fe a Co b O x and polymer nanofilm coating play major roles on their high catalytic activity and stability. The nanofilm-coated Fe 3 Co 16 O x nanoparticles prepared under an optimized synthetic condition and calcined at 250 °C possesses higher surface area (134 m 2 /g), Co 3+ /Co 2+ ratio (1.89) and oxygen vacancy (20.5%), and thus exhibits the excellent catalytic performance for CO oxidation, such as, T 50 of −114 °C under normal moisture (3–10 ppm) and T 50 of 47 °C under moisture-rich (∼0.6 vol.%) conditions. Remarkably, compared with the published results, its much-improved long-term catalytic stability (>1 month) can be observed even at a very high moisture level (3.1 vol.%) 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. [ABSTRACT FROM AUTHOR]