Study on factors controlling catalytic activity for low-temperature water–gas-shift reaction on Cu-based catalysts

Influence of metal oxide added to Cu catalysts on the catalytic activity of the low-temperature water-gas-shift (LT-WGS) reaction was investigated. Catalytic activity was linearly correlated with both surface area of metallic copper (Cu0) and surface Cu content in the identical copper-metal oxide system. However, activity per Cu0 surface area changed depending on the metal oxide added. CO2-TPD profile demonstrated that the amount of strong basic sites on Cu–ZnOx and Cu–AlOx catalysts with high activity LT-WGS reactions was much less than those on Cu–FeOx and Cu–CeOx catalysts with low activity. Activity per Cu0 surface area increased with increasing amount of weak basic sites on Cu–AlOx and Cu–ZnOx catalysts. From these results, it is suggested that in addition to Cu0 surface area, basicity of a catalyst is one of the factors controlling the catalytic activity of Cu-based catalysts for LT-WGS reaction.

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► The linear correlation between WGS activity and Cu0 surface area was observed for each Cu-metal oxide system.
► WGS activity per Cu0 surface area was changed by metal oxide coexisting in Cu catalyst
► WGS activity per Cu0 surface area increased with increasing the amount of weak basic site.
► The amount of strong basic site on catalyst showing high activity was much less than that on catalyst showing low activity.