Indium-based Catalysts for CO2 Hydrogenation to Methanol: Key Aspects for Catalytic Performance

Abstract

CO2 hydrogenation utilizing sustainably produced hydrogen and CO2 derived from industrial exhaust gas represents a pivotal technology for chemical energy storage and climate change mitigation. This work aims to identify the best combination of catalyst support, synthesis method and promotor for In2O3/ZrO2 catalysts in a typical fixed-bed configuration. Intense characterization using ICP-OES, XRD, XPS, N2-physisorption, CO2-TPD, H2-TPR and SEM-EDX provide molecular insights into the different effects caused by various synthesis methods and doping elements. Doping the most promising In2O3/ZrO2 (M-SG) catalyst with 0.7 wt. % NiO by wetness impregnation using an ethanol/water mixture as a solvent, an increased methanol production rate of 0.497 gMeOH ⋅ (Formula presented.) ⋅ h−1 could already be achieved at 250 °C. Hereby, the low amount of highly dispersed NiO promotes H2 activation via hydrogen spillover, leading to sustained catalytic activity for 100 hours of time-on-stream.