C2-oxygenates synthesis through CO hydrogenation on SiO2-ZrO2 supported Rh-based catalyst: The effect of support

Rh-Mn-Li catalysts supported on SiO2, ZrO2 and SiO2-ZrO2 mixed oxides with various molar ratios of Si/Zr were prepared and tested for the synthesis of C2-oxygenates from syngas. Compared with pure SiO2 and ZrO2 supported catalysts, catalysts supported on SiO2-ZrO2 mixed oxides showed higher activity and C2-oxygenates selectivity, in which Rh-Mn-Li/SiO2-ZrO2 (molar ratio of Si/Zr = 1:3) exhibited the best yield of C2-oxygenates. The effect of the support on the performance of the Rh-based catalysts was investigated comprehensively by XRD, N2 adsorption-desorption, H2 and CO uptakes, FT-IR, XPS, H2-TPR, TPSR and CO-TPD techniques. The results indicated that the chemical state of Rh, CO adsorption species, dispersion of Rh and the ability of CO hydrogenation varied over catalysts supported on SiO2, ZrO2 and SiO2-ZrO2 mixed oxides, which led to the diverse catalytic activity toward C2-oxygenates synthesis.

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► SiO2-ZrO2 supported catalyst exhibited better activity and C2 oxygenates selectivity.
► SiO2-ZrO2 supported catalyst has higher dispersion of Rh.
► SiO2-ZrO2 supported catalyst has more Rh+ sites for CO insertion.
► SiO2-ZrO2 supported catalyst promotes CO dissociation.
► SiO2-ZrO2 supported catalyst has moderate ability for hydrogenation.