Strong Electronic Oxide–Support Interaction over In 2 O 3 /ZrO 2 for Highly Selective CO 2 Hydrogenation to Methanol

Metal oxides are widely employed in heterogeneous catalysis, but it remains challenging to determine their exact structure and understand the reaction mechanisms at the molecular level due to their structural complexity, in particular for binary oxides. This paper describes the observation of the strong electronic interaction between In 2 O 3 and monoclinic ZrO 2 (m-ZrO 2 ) by quasi-in-situ XPS experiments combined with theoretical studies, which leads to support-dependent methanol selectivity. In 2 O 3 /m-ZrO 2 exhibits methanol selectivity up to 84.6% with a CO 2 conversion of 12.1%. Moreover, at a wide range of temperatures, the methanol yield of In 2 O 3 /m-ZrO 2 is much higher than that of In 2 O 3 /t-ZrO 2 (t-: tetragonal), which is due to the high dispersion of the In–O–In structure over m-ZrO 2 as determined by in situ Raman spectra. The electron transfer from m-ZrO 2 to In 2 O 3 is confirmed by XPS and DFT calculations and improves the electron density of In 2 O 3, which promotes H 2 dissociation and hydrogenation of formate intermediates to methanol. The concept of the electronic interaction between an oxide and a support provides guidelines to develop hydrogenation catalysts.