Performance of catalysts CuO-ZnO-Al2O3, CuO-ZnO-Al2O3-Pt-Rh, and Pt-Rh in a small reformer for hydrogen generation

This study experimentally investigates the performances of catalysts CuO-ZnO-Al2O3, CuO-ZnO-Al2O3-Pt-Rh, and Pt-Rh in a reformer designed to generate hydrogen from a solution of methanol and water for proton exchange membrane (PEM) fuel cell. The results show that both of the methanol conversion and the hydrogen yield rates increase with temperature. For the three catalysts tested, catalyst CuO-ZnO-Al2O3 provides the best performance at temperatures lower than 320 °C. However, at higher temperatures, the performance of this catalyst deteriorates, while that of CuO-ZnO-Al2O3-Pt-Rh and Pt-Rh continue to improve. It suggests that the addition of Pt and Rh to the original CuO-ZnO-Al2O3 catalyst has a stabilizing effect upon the reforming process under higher temperature conditions. The results also show that a higher methanol feed rate reduces the methanol conversion rate, but increases the hydrogen yield rate. It is found that both of the methanol conversion and the hydrogen yield rates reduce as the steam-to-methanol ratio is increased. Finally, the performance can be significantly improved by introducing a turbulence inducer upstream of the catalyst carrier and by increasing both the length and the cell density of the honeycomb structure.