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

Abstract

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.