Influence of metal oxide added to Cu catalysts on the catalytic activity for the low-temperature water-gas-shift (LT-WGS) reaction was investigated. The catalytic activities were linearly correlated with surface area of metallic copper in the identical copper-metal oxide system; however the activity per Cu0 surface area was changed by metal oxide added. CO2-TPD profile demonstrated that the amounts of strong basic site on Cu-ZnOx and Cu-AlOx catalysts with high activity for LT-WGS reaction were much less than those on Cu-FeOx and Cu-CeOx catalysts with low activity. The activity per Cu0 surface area increased with increasing the amount of weak basic site on Cu-AlOx and Cu-ZnOx catalysts. From the present results, it is suggested that basicity of catalyst is one of the factors controlling the catalytic activity of Cu-based catalysts for LT-WGS reaction in addition to Cu0 surface area. Influence of coexisting Al2O3 on the catalytic activity for LT-WGS reaction over Cu catalyst was also investigated. The catalytic activity of Cu/Al2O3 catalyst increased with decreasing mesopore size when S/C ratio was 2.2, whereas the catalytic activity with S/C ratio = 4.6 increased with increasing mesopore size. IR measurement combined with kinetic study suggested that the low catalytic activity of Cu/CeO2 catalyst comes from the restriction of CO adsorption on Cu0 by bidentate-type carbonate formed on the strong basic site of CeO2 support. On the other hand, it was found that bidentate-type carbonate was not formed on Cu/Al2O3 showing high catalytic activity for LT-WGS reaction.

Influence of coexisting metal oxide on the activity of copper catalyst for water-gas-shift reaction

249th National Meeting (2015)

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