Dry and Steam Reforming of CH4 on Co-Hexaaluminate: On the Formation of Metallic Co and Its Influence on Catalyst Activity

• Published in: Industrial & engineering chemistry research Vol. 59; no. 42; pp. 18790 - 18797
• Main Authors: Giehr, Andreas, Maier, Lubow, Angeli, Sofia, Schunk, Stephan A, Deutschmann, Olaf
• Format: Journal Article
• Language: English
• Published: American Chemical Society 21.10.2020
• Subjects: Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.0c03522

Dry and steam reforming of methane is studied over Co-hexaaluminate as a prospective coking-resistant transition-metal catalyst. Kinetic measurements and X-ray diffraction investigations reveal that the formation of metallic Co and the activity of the catalyst are strongly affected by the gas composition. While co-feeding of H2 proves to be beneficial to the conversion of methane, decreasing the ratio of CH4 to the oxidant in the feed gas is found to be detrimental to the activity of the catalyst. A considerable inhibition effect is demonstrated particularly in the presence of H2O. As the local gas composition inside the reactor varies with conversion, axial changes in the degree of Co reduction are observed. A microkinetic model is proposed, which accounts for the varying fractions of oxidic and metallic Co by means of oxygen surface coverages, to perform steady-state reactor simulations. Strengths and weaknesses of the approach are critically evaluated by comparing experimental and simulation results.