Rich oxygen vacancies in In2O3/ZnO heterostructure for boosting CO2 hydrogenation to methanol

Abstract

The hydrogenation of carbon dioxide aims to reduce the concentration of carbon dioxide in the atmosphere and convert it into valuable chemicals or fuels. This reaction is of great significance in addressing climate change, reducing greenhouse gas emissions, and achieving carbon dioxide recycling. In the reaction of carbon dioxide hydrogenation to methanol, efficient and stable catalyst is one of the important factors for the efficient conversion of carbon dioxide to methanol. However, the currently reported catalysts basically need to play a catalytic role at higher temperatures and pressures. Therefore, the development of a catalyst that can maintain high activity at lower temperatures and pressures remains an urgent challenge. In this study, In₂O₃/ZnO heterostructure catalysts were prepared by water bath combined with subsequent Solvothermal method. At 250 °C and 2 MPa, the CO₂ conversion of In₂O₃/ZnO-2 catalyst was 13.5 %, the methanol selectivity was 83.3 %, and the methanol space-time yield (STY) was 0.437 g·g_cat⁻¹·h⁻¹, which was 4.8 times and 2.9 times that of pure In₂O₃ (0.091 g·g_cat⁻¹·h⁻¹) and CP-In₂O₃/ZnO (0.151 g·g_cat⁻¹·h⁻¹), respectively. The formation of In₂O₃/ZnO heterostructure, large specific surface area and more exposed active sites, as well as abundant oxygen vacancies in the material, promote the good catalytic performance of In₂O₃/ZnO-2 catalyst. It is expected that this novel In₂O₃/ZnO heterostructure catalyst will provide new ideas and inspiration for the design and development of bimetallic oxide catalysts with high activity and selectivity for carbon dioxide hydrogenation to methanol at lower temperatures and pressures.