Preferential oxidation of CO on copper-containing manganese oxides

Copper-containing manganese oxides (Cu/Mn (molar ratio) = 0–1/1) prepared by the sol–gel method were characterized by temperature-programmed desorption of CO (CO-TPD) and of H2 (H2-TPD), temperature-programmed reduction with H2 (H2-TPD), and competitive adsorption of CO and H2. Copper-containing manganese oxides (amorphous structure, mesopores of about 6 nm, and high surface areas of 170–230 m2 g−1) were used for preferential oxidation (PROX) of CO in a large excess of H2. It was observed that copper-containing manganese oxides could preferentially and totally oxidize 1 vol% CO at temperature lower than 100 °C. The reason for high O2 selectivity to CO oxidation was discussed. Preferential adsorption of CO to H2 on the highly active sites and low activity of the manganese oxide-based catalysts to oxidize H2 were the reasons for the favorable performance.

Copper-containing manganese oxides were studied for the preferential CO oxidation in H2-rich stream (1 vol% CO, 1 vol% O2, 60 vol% H2 and balance N2). Preferential and complete conversion of CO was attained at 75 °C with substantially 100% O2 selectivity. Preferential adsorption of CO on the highly reactive site and low H2-oxidation activity of the catalysts contributed to the excellent performance.Figure optionsDownload as PowerPoint slide