Experimental and kinetic modeling of CO2 hydrogenation to methanol over Cu/ZnO/ZrO2 catalysts

Abstract

ABSTRACT With the change of the global climate, the technology of hydrogenation of CO2 to methanol has attracted considerable attention all over the world. In this work, the hydrogenation of carbon dioxide to methanol over Cu/ZnO/ZrO2 catalysts is carried out at atmospheric pressure. The effect of process conditions on the catalytic performance is examined to determine the most effective conditions. The reaction kinetics are then investigated by using two Langmuir–Hinshelwood (L–H) kinetic models. The kinetic parameters are determined and statistical tests and residual analyses indicate that both kinetic models are reliable. However, the fitting effects for CO2 and CO are different between the two models. Moreover, the structural characteristics of the catalytic under different conditions are examined by TEM, XRD, and XPS. It can also be found that oxygen vacancies can facilitate the activation of carbon dioxide and the desorption of methanol during the reaction. The reactants and products undergo reactions in which oxygen migrates and reoxidation occurs with surface oxygen vacancies, resulting in an increase in the concentration of oxygen vacancies.