Research on CuO/CeO2-ZrO2/SiC Monolithic Catalysts for Hydrogen Production by Methanol Steam Reforming

Hydrogen proton exchange membrane fuel cell is considered as the most cleanest way with high energy efficiency of hydrogen energy utilization. However, the high storage and transportation cost of hydrogen can always be the important factors hindering its development. Fortunately, on-site hydrogen production from methanol steam reforming can effectively solve this problem, which has low reforming temperature and CO content in reforming gas. Monolithic catalyst, a kind of catalytic material, on which the active components loaded on the formed support are generally honeycombed structures with multiple parallel channels. Therefore, compared to the traditional beaded catalytic materials, the monolithic catalytic material has lower pressure drop and higher mass transfer efficiency, which means that the monolithic catalysts have a certain practical application prospect. Ceria-zirconia solid solution was prepared by the sol-gel method, then a series xCuO/CeO2-ZrO2/SiC catalysts were prepared by incipient-wetness impregnation method, and demonstrated considerable catalytic activity at high velocity reaction conditions. The catalyst samples were characterized by X-ray diffraction (XRD), BET specific surface area test, H-2-temperature programmed reduction (H-2-TPR), X-ray photoelectron spectroscopy (XPS) techniques. According to the results, we proposed that the catalytic performances are mainly effected by the surface area of Cu, the interaction between active component and support, and the amount of oxygen vacancy. Among those catalysts, 5%CuO/CeO2-ZrO2/SiC had relatively higher copper specific surface area, stronger interaction between CuO and support, more oxygen vacancies, thus showing better catalytic activity. When the reaction temperature reached 360 degrees, with a water/methanol molar ratio of 1.2, methanol and water total gas hourly space velocity of 4840 h(-1), the methanol conversion reached 89.9%, and the H-2 production rate was 1556 L.m(-3).s(-1). When compared with the traditional bead catalyst, monolithic catalyst seems to be more suitable for high space velocity methanol steam reforming reaction, also the SiC support is chemical stable and has favorable thermal conductivity, which avoiding the device volume increase caused by the additional heating device, thus facilitating the integration of minitype reactors for hydrogen generation.