Tuning surface-interface structures of ZrO2 supported copper catalysts by in situ introduction of indium to promote CO2 hydrogenation to methanol

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Currently, highly efficient catalytic CO2 hydrogenation to produce methanol is attracting intensive attention. However, constructing high-performance catalysts for methanol synthesis that can be operated under mild reaction conditions is a challenging task. In this work, a series of indium-doped ZrO2 supported copper-based catalysts for CO2 hydrogenation were constructed via one-pot hydrogen bubble-assisted approach. It was manifested that the in situ introduction of indium facilitated the generation of interfacial defects in the form of Zr-Vo-In3+ structure (Vo: oxygen vacancy) and interfacial Cu+ sites, as well as surface basic sites originating from In-O pairs, and the catalytic performance of as-constructed In-doped Cu/ZrO2 catalysts could be efficiently promoted by tuning the indium content. Specifically, the Cu-based catalyst bearing the indium content of 4.0 wt% afforded the quite high space-time yield of methanol (0.398 gMeOH h−1·gcat−1) at 270 °C, while the one with the indium content of 8.0 wt% yielded an increased methanol selectivity by 1.8 times at 250 °C, compared with undoped one. Combining the structural characterizations with catalytic results, it was found that surface medium-strength and strong basic sites together with the contribution from interfacial defective oxygen vacancies and Cu+ sites played key promotional roles on the synthesis of methanol. This finding enables us to design new high-performance Cu-based catalysts for CO2 hydrogenation by finely turning their surface-interface structures.