Effect of Conversion, Temperature and Feed Ratio on In2O3/In(OH)3 Phase Transitions in Methanol Synthesis Catalysts: A Combined Experimental and Computational Study

Abstract

AbstractCatalytic hydrogenation of CO2 to methanol has attracted lots of attention as it makes CO2 useable as a sustainable carbon source. This study combines theoretical calculations based on the dummy catalytic cycle model with experimental studies on the performance and degradation of indium‐based model catalysts for methanol synthesis. In detail, the reversibility of phase transitions in the In2O3/In(OH)3 system under industrial methanol synthesis conditions are investigated depending on conversion, temperature and feed ratio. The dummy catalytic cycle model predicts a peculiar degradation behavior of In(OH)3 at 275 °C depending on the water formed either by methanol synthesis or the competing reverse water‐gas‐shift reaction. These results were validated by dedicated experimental studies confirming the predicted trends. Moreover, X‐ray diffraction and thermogravimetric analysis proved the ensuing phase transition between the indium species. Finally, the validated model is used to predict how hydrogen drop out will affect the stability of the catalyst and derive practical strategies to prevent irreversible catalyst degradation.