Acetic acid steam reforming to hydrogen over Co–Ce/Al2O3 and Co–La/Al2O3 catalysts—The promotion effect of Ce and La addition

Steam reforming of acetic acid was investigated over Co–Ce/Al2O3 and Co–La/Al2O3 catalysts. Ce addition affected negligibly the activity of Co/Al2O3 catalyst but affected the product distribution significantly. The formations of acetone and ketene by-products were inhibited by the addition of Ce, resulting in much higher hydrogen yield. La addition remarkably enhanced low-temperature reforming activity. Both acetic acid and the by-products acetone and ketene could be steam reformed efficiently into hydrogen. Moreover, the Co–Ce/Al2O3 and Co–La/Al2O3 catalysts presented much better stability, due to the promotion of Ce and La on the catalyst resistivity to metallic phase oxidation and coke formation.

The significant amount of coke formation resulted in rapid deactivation of the Co/Al2O3 catalyst in the stability test, while the addition of Ce or La to Co/Al2O3 could effectively eliminate carbon deposition on the catalyst surface through inhibition of the reaction pathways for coke formation.Figure optionsDownload as PowerPoint slideResearch Highlights
► The addition of Ce to Co/Al2O3 shows negligible effect on catalytic activity but significantly suppresses production of the organic by-products: acetone and ketene.
► The addition of La to Co/Al2O3 catalyst enhances the dispersion of Co, and hence promotes both the reforming activity and hydrogen selectivity.
► Co–Ce/Al2O3 and Co–La/Al2O3 catalysts present much better stability, due to the promotion effects of Ce and La on the catalyst resistivity toward metallic phase oxidation and coke formation.