Production and Utilization of Hydrogen Carriers by Using Supported Nickel Catalysts

Utilization of hydrogen carriers is an important method for the storage and transportation of hydrogen energy. We have investigated supported nickel catalysts for methane production from hydrogen and carbon dioxide, and hydrogen production from ammonia. In the methane production, methane yield was drastically enhanced at 225-250 °C and reached maximum at 300-350 °C for most catalysts tested. CO2 desorption behavior over the catalysts indicated that moderate basic sites should positively affect the catalytic activity for the reaction. According to the infrared spectroscopic analyses, CO2 methanation over Ni/Al2O3 proceeded via the formation of CO intermediate, whereas the formate adsorbate would be the main intermediate over Ni/Y2O3. For the hydrogen production from ammonia, rare-earth oxide-supported catalysts showed relatively high performance despite the low surface area of the support materials. Ammonia conversion over Ni/Y2O3 reached 87 % at 550 °C. Rare-earth components were also effective as additives for the Ni/Al2O3 catalyst. These results were derived from the alleviation of hydrogen inhibition by rare-earth materials.