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 Co3O4-CeO2 catalysts on modified activated carbon (AC) for eliminating the trace CO from H2-rich gases. The effects of support modification by H2O2 oxidation treatment, catalyst calcination temperature, Ce/Co atomic ratio (nCe/Co), Co3O4-CeO2 loading and reaction parameters on catalytic properties of the Co3O4-CeO2/AC catalysts were investigated. Various characterization techniques like scanning electron microscopy (SEM), X-ray diffraction (XRD) and H2 temperature-programmed reduction (H2-TPR) were employed to reveal the relationship between catalysts nature and catalytic performance. Results illustrate that the supported Co3O4-CeO2 catalyst on modified AC exhibits excellent catalytic properties, which highly depends on dispersity and reducibility of Co3O4 affected by the time of support treatment (tp), calcination temperature, nCe/Co and loading. The supported 35 wt% Co3O4-CeO2 catalyst (1:8 of nCe/Co) on the modified AC with H2O2 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 CO2 and H2O in the feed. The optimized Co3O4-CeO2/AC may be a robust and promising catalyst for eliminating trace CO from H2-rich gases.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Optimized Co3O4-CeO2/AC may be a robust and promising catalyst for CO PROX reaction. ► The active species reducibility and dispersity strongly affect catalytic properties. ► H2O2 treatment markedly improves the catalytic activity of Co3O4-CeO2/AC catalyst. ► Optimal component and preparation parameters are essential to Co3O4-CeO2/AC. ► Formation of Co-Ce-O phase via Co–Ce interaction benefits for CO PROX reaction.