Supported Co3O4-CeO2 catalysts on modified activated carbon for CO preferential oxidation in H2-rich gases

CO preferential oxidation (PROX) reactions were performed over the supported Co 3 O 4 -CeO 2 catalysts on modified activated carbon (AC) for eliminating the trace CO from H 2 -rich gases. The effects of support modification by H 2 O 2 oxidation treatment , catalyst calcination temperature, Ce/Co atomic ratio ( n Ce/Co ), Co 3 O 4 -CeO 2 loading and reaction parameters on catalytic properties of the Co 3 O 4 -CeO 2 /AC catalysts were investigated. Various characterization techniques like scanning electron microscopy (SEM), X-ray diffraction (XRD) and H 2 temperature-programmed reduction (H 2 -TPR) were employed to reveal the relationship between catalysts nature and catalytic performance. Results illustrate that the supported Co 3 O 4 -CeO 2 catalyst on modified AC exhibits excellent catalytic properties, which highly depends on dispersity and reducibility of Co 3 O 4 affected by the time of support treatment ( t p ), calcination temperature, n Ce/Co and loading. The supported 35   wt% Co 3 O 4 -CeO 2 catalyst (1:8 of n Ce/Co ) on the modified AC with H 2 O 2 oxidation treatment for 6   h demonstrates the best catalytic properties and the almost complete CO transformation takes place in a wide temperature range of 125–190   °C. Moreover, it is also found that the developed catalyst exhibits an outstanding catalytic stability, and 100% CO conversion can be maintained as the time on stream evolutes up to 1800   min even in the presence of CO 2 and H 2 O in the feed. The optimized Co 3 O 4 -CeO 2 /AC may be a robust and promising catalyst for eliminating trace CO from H 2 -rich gases.