Catalytic performance on CuO–Cr2O3–Ga2O3 mixed oxides for water gas shift reaction: Effects of Ga/Cr molar ratio

Water gas shift (WGS) reaction was carried out on the coprecipitated CuO–Cr2O3–Ga2O3 mixed oxides to elucidate the effects of Ga2O3 species to catalytic performances. WGS catalysts are prepared at a fixed molar ratio of Cu/(Cr + Ga) at 1.0/0.1 by varying Ga/Cr molar ratio from 0 to 4. The catalytic activities on CuO–Cr2O3–Ga2O3 are found to be in the shape of volcano curve in terms of Ga/Cr molar ratio and the highest activity was observed on the catalyst having equimolar ratio of Ga/Cr in all tested temperature ranges of 160–280 °C. The observed activities are strongly related with the metallic surface area of copper crystallites, and the high surface area of metallic copper could be obtained by controlling the formation rate of copper–chromium nuclei at an optimum Ga/Cr molar ratio on CuO–Cr2O3–Ga2O3 mixed oxides.

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► Water gas shift reaction was carried out on CuO–Cr2O3–Ga2O3 ternary mixed oxides.
► The activities are found to be in the shape of volcano curve with respect to Ga/Cr molar ratio.
► The highest activity was observed on the catalyst having an equimolar ratio of Ga/Cr.
► The activities are related with metallic surface area of copper adjusted by varying Ga/Cr ratio.