Dynamic Restructuring of Rh/In ₂ O _{3– <i>x</i>} on ZrO ₂ Support for Promoted Selective Hydrogenation of CO ₂ to Methanol

The Rh/In2O3/ZrO2 ternary catalyst exhibits higher activity for the selective CO2 hydrogenation to methanol compared to the Rh/In2O3 catalyst. The dynamic structural and chemical evolution of In2O3 under reaction conditions plays a pivotal yet underexplored role in governing the catalytic behavior of Rh/In2O3/ZrO2. Through comparative investigations of Rh/In2O3/ZrO2 and Rh/ZrO2 catalysts, the critical role of In2O3 is elucidated in modulating the structural and electronic configurations of the active sites. The analyses with in situ transmission electron microscopy (TEM), in situ Raman spectroscopy, and quasi in situ X-ray photoelectron spectroscopy (XPS) reveal the transformation of cubic In2O3 into disordered In2O3–x nanolayers on ZrO2, creating abundant In2O3–x/ZrO2 interfaces enriched with oxygen vacancies. Simultaneously, the restructured Rh/In2O3–x interface induces pronounced metal–support interactions, synergistically enhancing CO2 chemisorption while maintaining the H2 dissociation capability. This dual functionality preferentially stabilizes HCOO* intermediates, dramatically shifting product selectivity from methane (97.0%) over Rh/ZrO2 to methanol (81.0%) with ignorable methane formation on Rh/In2O3/ZrO2, at 300 °C and 5 MPa, as an example. This work shows the effect of the In2O3-mediated dynamic reconstruction on the selection of the reaction pathway for CO2 hydrogenation. The new insights into the structure–activity relationship of the Rh/In2O3/ZrO2 catalyst are provided.