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

Abstract The efficiency of gold supported on Mn 2 O 3 -Fe 2 O 3 mixed oxides in the preferential oxidation of CO to CO 2 in H 2 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 Mn 2 O 3 and Fe 2 O 3 . 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.% O 2 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% CO 2 to the feed caused reduction in the conversion of CO, while the introduction of 8.8 vol% H 2 O did not affect CO conversion, but mitigated the negative effect of CO 2 . All catalysts showed complete CO conversion up to 250 °C in total CO oxidation experiments when sufficient oxygen was supplied to the system.