Production of hydrogen by partial oxidation of methanol over bimetallic Au–Cu/TiO 2–Fe 2O 3 catalysts

Abstract

Partial oxidation of methanol (POM) to produce H 2 was investigated over Au–Cu/TiO 2 and Au–Cu/TiO 2–Fe 2O 3 catalysts. The catalysts were prepared by deposition-precipitation method and characterized by XRD, TEM, HRTEM, ICP-AES, TPR, NH 3-TPD and XPS analyses. Detail study on the Au–Cu/TiO 2–Fe 2O 3 catalysts was performed to optimize Ti/Fe ratio, pH during preparation of the catalyst, calcination temperature and reaction temperature. The Au–Cu/TiO 2–Fe 2O 3 catalyst with Ti/Fe = 9/1 atomic ratio is more active and exhibits higher methanol conversion compared to the Au–Cu/TiO 2 catalyst. The higher activity of Fe-containing catalyst was attributed to the ability to supply reactive oxygen, thereby stabilize active gold species (Au δ+ ) in the catalyst. Studies on the optimization of pH during preparation of the Au–Cu/TiO 2–Fe 2O 3 catalyst and calcination temperature showed that the catalyst prepared at pH 7 and dried at 373 K (uncalcined) exhibited higher activity. The catalytic performance at various reaction temperatures shows that both methanol conversion and hydrogen selectivity are increased with increasing the temperature. A small increase in CO selectivity was observed beyond 523 K, which is due to the decomposition of methanol and reverse water gas shift at high temperatures.