Triple the steady-state reaction rate by decorating the In2O3 surface with SiO for CO2 hydrogenation

Indium oxide (In2O3), as a promising candidate for CO2 hydrogenation to C1 products, often suffers from sintering and activity decline, closely related to the undesirable structural evolution under reaction conditions. Based on the comprehension of the dynamic evolution, this study presents an efficient strategy to alleviate the agglomeration of In2O3 nanoparticles by the surface decoration with highly dispersed silica species (SiOx). Various structural characterizations combined with density functional theory calculations demonstrated that the sintering resulted from the over-reduction, while the enhanced stability originated from the anchoring effect of highly stable In–OSi bonds, which hinders the substantial formation of metallic In (In0) and the subsequent agglomeration. 0.6Si/In2O3 exhibited CO2 conversion rate of 10.0 mmol g−1 h−1 at steady state vs. 3.5 mmol g−1 h−1 on In2O3 in CO2 hydrogenation. Enhanced steady-state activity was also achieved on Pd-modified catalysts. Compared to the traditional Pd/In2O3 catalyst, the methanol production rate of Pd catalyst supported on 0.6Si/In2O3 was enhanced by 23%, showing the potential of In2O3 modified by SiOx in serving as a platform material. This work provides a promising method to design new In2O3-based catalysts with improved activity and stability in CO2 hydrogenation.