Oxidation of carbon monoxide over supported nickel oxide catalyst: kinetic model development and identification

• Published in: South African journal of chemical engineering 2022-01, Vol.39, p.106-116
• Main Authors: Maharaj, Christine, Lokhat, David, Rawatlal, Randhir
• Format: Article
• Language: English
• Subjects: Adsorption; Aluminum oxide; Analysis; Carbon monoxide; Carbon monoxide oxidation; Nickel; Nickel oxide catalyst; Oxidation-reduction reaction; Reaction kinetics
• ISSN: 1026-9185
• DOI: 10.1016/j.sajce.2021.12.001

•The oxidation rate of carbon monoxide (CO) over Ni/Al2O3 catalyst was found to be dependent on the reaction temperature and both the reactant partial pressures of oxygen and CO.•The CO oxidation rate was observed to increase with an increase in the reaction temperature and an increase in the reactant partial pressures.•The kinetic model based on low temperature non-competitive adsorption of reactant and product species onto catalyst surface sites better fit the experimental data than the models based on Langmuir-Hinshelwood and Eley-Rideal type reaction mechanisms.•This model displayed reasonable agreement with the experimental data with a coefficient of determination (R2) value of 0.717 being obtained. The kinetics of carbon monoxide oxidation over alumina supported nickel oxide was studied using a mechanistic approach to model development and identification. Langmuir-Hinshelwood and Eley-Rideal reaction schemes, together with an alternative scheme were investigated, using low temperature, differential rate measurements. Experimental results were found to be most consistent with the alternative scheme, supporting a reaction mechanism based on non-competitive adsorption of carbon monoxide and oxygen onto different catalyst sites without mutual displacement. The resulting kinetic model was observed to have reasonable agreement with the experimental findings and was found representative of the system.