Activity enhancement of Cu-doped ceria by reductive regeneration of CuO–CeO 2 catalyst for preferential oxidation of CO in H 2-rich streams

Abstract

Effect of short periods of reduction, in CO and H 2 feed, on regeneration and activity enhancement of a 5.0 wt.% CuO–CeO 2 catalyst for preferential oxidation of CO in a H 2-rich stream at various temperatures is investigated. The catalyst was prepared by a co-precipitation method, calcined at 450 °C for 5 h, and characterized by XRD, FESEM, EDS, BET specific surface area, H 2-TPR and CO 2-TPD. It was found that fine crystallites/amorphous CuO are dispersed on CeO 2 particles with average size of about 33 nm. A gas mixture composed of 1% CO, 40% H 2 and 1% O 2 in N 2 was used as the feed for measurements of the catalyst performance at various temperatures. CO 2 and H 2O were also added to the feed, to study their inhibitive effects on the activity of the catalyst. The activity of the catalyst for CO oxidation significantly enhances after transient reduction in CO and H 2 feed. Higher activity enhancements are observed at lower temperatures and shorter reduction periods. Up to 35% enhancement is observed following 3 min reduction at 100 °C. The most reactive Cu 1+ species may have formed during the reduction period and regenerates the catalyst leading to higher CO oxidation activities.