Low Ag concentration Ag/CeO₂ catalysts prepared with various CeO₂ precursors in carbon monoxide oxidation reaction

Ag/CeO₂ catalysts for the CO oxidation reaction were synthesized by the metal-vapor method. Highly dispersed cerium dioxide used as a carrier was obtained by precipitation of Ce⁺³ ions with various (NH₄OH, (NH₄)₂CO₃ and H₂C₂O₄) precipitators and subsequent calcination in an oxidizing atmosphere. CeO₂ particles were formed with different morphologies depending on the precipitator used. When using NH₄OH, mainly spheroidal particles are formed, while the shape of platelets is typical for the use of H₂C₂O₄. The samples were characterized by EDX, SEM, TEM, XPS, low-temperature nitrogen adsorption. Catalytic testing of the samples was carried out in an oxidation reaction using gas chromatography. It was found that the catalytic activity of the samples decreases in a series Ag/CeO_2carb > Ag/CeO_2oxal > Ag/CeO_2hydr. Ag/CeO_2oxal catalysts demonstrated relatively high activity and the most stable operation over 10 cycles.