Water–gas shift reactions on potassium- and zirconium-promoted cobalt molybdenum carbide catalysts

The preparation of carburized CoMo with alumina, potassium or zirconium added and their activity for the water–gas shift reaction at 453 K were investigated on the basis of XRD, temperature-programmed desorption (TPD) after H218O adsorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The carburized 5 wt% Al2O3/Co46.5Mo46.5K2Zr5 catalyst exhibited the highest CO conversion and TOF. The TPD experiment after H218O adsorption showed that the Zr-containing catalysts produced Co6Mo6C1 from β-Mo2C and Co metal, but the catalyst without zirconium produced MoO2 and Co3Mo. The presence of potassium significantly promotes water dissociation while zirconia prevented the oxidation of β-Mo2C. The Al2O3KZr-promoted CoMo catalyst exhibited a higher distribution of Co0 and Co2+ than the catalysts containing either zirconium or potassium in the presence of the Co3+ ions. The Al2O3KZr-promoted CoMo catalyst contained β-Mo2C, small Co metal particles and Co6Mo6C1 along with zirconia, potassium and alumina.

The preparation of carburized CoMo with alumina, potassium or zirconium added and their activity values for the water–gas shift reaction at 453 K were investigated. The presence of potassium significantly promoted water dissociation and that of zirconia prevented the oxidation of β-Mo2C during reaction on the carburized 5 wt%Al2O3/Co46.5Mo46.5K2Zr5 catalyst.Figure optionsDownload high-quality image (62 K)Download as PowerPoint slide