Partial Oxidation of Methanol (POM) over Transition Metal-Promoted Nanostructured Gold Catalysts Supported on CeO2-ZrO2

Partial methanol oxidation (POM) is one of the possible routes for H-2 generation onboard for fuel cell-driven vehicles. The reaction was carried out with a stoichiometric ratio of CH3OH to O-2 in the feed following the equation CH3OH + 1/2O(2) -> CO2 + 2H(2). Transition metals (Fe, Ni, Co, Cu, and Zn) were used as a promoter over Au/CeO2-ZrO2 to catalyze POM reaction in the temperature range of 325-450 degrees C. The support was prepared from mechanically mixing of CeO2 and ZrO2. Transition metals were deposited using the impregnation method, and the deposition-precipitation method was used to deposit Au on the samples containing transition metals. A combination of methods like low-temperature N-2 adsorption, powder XRD, TPR with H-2, and XPS were used to evaluate the physicochemical, structural, and surface properties of the synthesized catalysts. Fe- and Cu-promoted catalysts were found less attractive due to low H-2 selectivity. Ni- and Co-promoted catalysts showed a promising H-2 selectivity but suffered from high CO selectivity. Interestingly, over 83% selectivity toward H-2 and less than a 16% CO selectivity with 95% CH3OH conversion were found for Zn-modified Au/CeO2-ZrO2 samples at 450 degrees C, giving the highest yield for H-2 (similar to 80%) among all the investigated catalysts in this study, which makes it a promising catalyst for this process. Moreover, below 400 degrees C, Zn-promoted catalyst showed the lowest CO selectivity compared to Co- and Ni-promoted one.

Automated summary

Partial methanol oxidation (POM) is a possible route for hydrogen generation in fuel cell-driven vehicles. Transition metals (Fe, Ni, Co, Cu, and Zn) were used as promoters over Au/CeO2-ZrO2 to catalyze the POM reaction. Among them, Zn-modified Au/CeO2-ZrO2 samples showed the highest yield for hydrogen (around 80%) with over 83% selectivity and less than 16% CO selectivity at 450 degrees C, making it a promising catalyst for the process.