Hydrogen production via steam reforming of methanol using Cu/ZnO/Al2O3: Effect of catalyst synthesis method and Cu to Zn molar ratio on physico-chemical properties and catalytic performance

Abstract

This research investigates the steam reforming of methanol (SRM) using Cu/ZnO/Al2O3 catalysts synthesized via three distinct methods: coprecipitation, hydrothermal, and sol-gel methods. A comprehensive analysis of the catalysts' physicochemical, morphological, and thermal properties was conducted, and their catalytic performances were compared. The coprecipitation method yielded catalysts with desirable catalytic properties, including high specific surface area, increased Cu0 area, increased Cu dispersion, and improved reducibility, leading to the highest catalytic performance compared to the other methods tested. These catalysts exhibited the highest methanol conversions of 91.5% and H2 yield of 90.9%, with a low CO selectivity of 0.61% at 280 °C. In contrast, catalysts synthesized via hydrothermal and sol-gel methods showed lower methanol conversions of 39.2% and 73.5%, H2 yields of 39.0% and 72.7%, and CO selectivity of 1.46% and 0.91%, respectively, at the same temperature. Further investigation of the coprecipitated catalysts involved varying the Cu/Zn molar ratios. The results revealed a noteworthy influence Cu/Zn ratio on the characterization results and catalytic performance. Notably, a Cu/ZnO/Al2O3 catalyst with a Cu to Zn ratio of 1 emerged as the optimal catalyst composition, demonstrating the highest catalytic performance for SRM.