Experimental work and kinetic modelling of CO₂ hydrogenation to methanol on CeO₂ supported In₂O₃ catalyst

This work investigates the kinetics of CO₂ hydrogenation to methanol on In₂O₃/ CeO₂ catalyst based on a dual-site Langmuir-Hinshelwood mechanism. Such studies on reaction kinetics and mechanism using In₂O₃ catalyst, which possesses high activity, selectivity and stability are limited. Thirteen sets of experimental data at steady-state using In₂O₃/ CeO₂ catalyst with varying temperature (200–300 °C), pressure (1–50 bars), gas hourly space velocity (5,893 hr⁻¹ −58,938 hr⁻¹) were analysed. The experimental data were modelled to determine the rate-determining step and the rate expression using the Most-Abundant Reaction Intermediate (MARI) analysis. The reaction mechanism for this catalyst was proposed based on a reported DFT study on In₂O₃. An optimisation procedure was performed to identify new kinetic parameters using MATLAB-based code with nonlinear regression analysis. A comparison of estimated kinetic parameters was made with reported values. The derived kinetic model can be applied for reactor modelling in the future for scaling up purposes.