Enhancing the Catalytic Oxidation of Carbon Monoxide Using K-OMS-2 by Surface Modification with Binary Oxides of Copper and Other Metals

With the goal of finding low-cost materials that can completely substitute the precious- and noble-containing catalysts and be active toward the oxidation of CO at low temperatures (around 100 °C), transition metal oxide-doped cryptomelane (e.g., K-OMS-2, MeOx/K-OMS-2, and CuOx-MeOx/K-OMS-2; Me = Ni, Fe, Cd, Sn, Mn, Cr, Co, Zn, and Al) were obtained by the impregnation method with different synthesis conditions. The synthesized samples were then tested for CO conversion and characterized by means of powder X-ray diffraction, elemental mapping and composition, as well as scanning electron microscopy. It was demonstrated that the K-OMS-2 support doped by a composite of CuOx-NiOx (promoter) and calcined at 400 °C gave higher catalytic activity than the other samples, with a 90