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

Indium oxide (In 2 O 3 ), as a promising candidate for CO 2 hydrogenation to C 1 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 In 2 O 3 nanoparticles by the surface decoration with highly dispersed silica species (SiO x ). 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 (In 0 ) and the subsequent agglomeration. 0.6Si/In 2 O 3 exhibited CO 2 conversion rate of 10.0 mmol g −1  h −1 at steady state vs. 3.5 mmol g −1 h −1 on In 2 O 3 in CO 2 hydrogenation. Enhanced steady-state activity was also achieved on Pd-modified catalysts. Compared to the traditional Pd/In 2 O 3 catalyst, the methanol production rate of Pd catalyst supported on 0.6Si/In 2 O 3 was enhanced by 23%, showing the potential of In 2 O 3 modified by SiO x in serving as a platform material. This work provides a promising method to design new In 2 O 3 -based catalysts with improved activity and stability in CO 2 hydrogenation.