Hydrogen generation from methanol oxidation on supported Cu and Pt catalysts: Effects of active phases and supports

Catalytic partial oxidation (CPO) of methanol was studied over Cu/ZnO and Pt/ZrO2 catalysts. These catalysts gave different results, with Cu/ZnO producing more CO2 and Pt/ZrO2 producing more CO. To explain this difference, the kinetics of four reactions (CPO, methanol decomposition (MD), methanol steam reforming (MSR), and water-gas shift (WGS)) were measured and used in a packed-bed model of the experimental reactor. For both catalysts, oxidation reactions were much faster than other reactions, so oxidation dominates the process until all of the oxygen is consumed. Once oxygen was depleted, MD dominated on Pt/ZrO2, keeping selectivity of CO high. On Cu/ZnO, however, MD was much slower, so MSR and WGS were dominant after oxygen had been consumed. In addition, deactivation of Cu/ZnO was investigated and it can be attributed to the existence of CH3O species or formate ions on the catalyst's surface. The effect of catalyst support was studied by adding ceria to Pt/ZrO2. While ceria addition appeared to enhance the importance of WGS, increased ceria loading led to higher selectivities of CO2 and H2O.

Graphical abstractCatalytic partial oxidation (CPO) of methanol was studied over Cu/ZnO and Pt/ZrO2 catalysts. The differences between these two are attributed to the reaction rates of CPO and methanol decomposition (MD). A packed-bed model was derived to predict the catalytic behaviors. In addition, deactivation of Cu/ZnO may be ascribed as deposition of methoxy species or formate ions on the catalyst's surface. Figure optionsDownload full-size imageDownload as PowerPoint slide