Remediation of CO by oxidation over Au nanoparticles supported on mixed metal oxides

Abstract

The efficiency of gold supported on Mn2O3-Fe2O3 mixed oxides in the preferential oxidation of CO to CO2 in H2 rich streams and in total oxidation is influenced by the particle size of gold. The mixed oxide precursors were prepared by co-precipitation. Gold nanoparticles were supported on the mixed oxides by deposition-precipitation technique using urea. X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD) analysis confirmed that the oxides formed during calcination of oxide precursors at 550 °C were Mn2O3 and Fe2O3. Gold particles with an average size of 3.7 nm produced a 99.5% CO conversion in the presence of hydrogen at 80 °C using 1 vol.% CO and 2 vol.% O2 with a gas hourly space velocity (GHSV) of 12 000 h−1 for preferential oxidation. The catalysts were also tested in a simulated reformate feed stream. The addition of 15 vol% CO2 to the feed caused reduction in the conversion of CO, while the introduction of 8.8 vol% H2O did not affect CO conversion, but mitigated the negative effect of CO2. All catalysts showed complete CO conversion up to 250 °C in total CO oxidation experiments when sufficient oxygen was supplied to the system.