Hydrogen Generation From Methanolysis Of Sodium Borohydride And The Performance Catalysts

Hydrogen generation from methanolysis of sodium borohydride has thefollowing advantages: high hydrogen generation and storage efficiency, highhydrogen purity, fast start-up reaction speed, easy control, and high safety. Inaddition, the byproduct NaB（OCH3）4can be easily dissolved in methanol andrecycled. More important, the methanolysis reaction can be carried out below0oC due to the low freezing point of methanol, making it to be the idealhydrogen sources for the fuel cells. At present, the researches related to themethanolysis of sodium borohydride are rather limited. Therefore, the studies oncatalysts and kinetics of the methanolysis reaction were conducted in this paper,which is expected to provide theoretical basis and technical support for theapplication of this new method of hydrogen generation.In this article, the studies were mainly focused on the Co/γ-Al₂O₃prepared byimpregnation-reduction method and nonmetal oxide modified P₂O₅/γ-Al₂O₃catalyst.The structure and morphology of the catalysts were characterized by X-raydiffraction （XRD）, scanning electron mictroscopy （SEM） fourier transform infraredspectroscopy （FTIR） and N₂adsorption-desorption. The effects of various factors,such as the reduction conditions, calcination temperature and time, on the structureand performance of the catalysts were mainly investigated. In addition, the effcts ofreaction temperature, concentration of sodium borohydride, concentration ofmethanol, and catalyst on the kinetics of the methanolysis reaction were alsostudied. The result shows that the methanolysis reaction can be effectively acceleratedby using Co/γ-Al₂O₃catalyst at solution temperature of0oC and provide a desirablehydrogen generation rate. The catalytic activity of Co/γ-Al₂O₃towards NaBH4methanolysis can be further improved by appropriate calcination treatment. Theγ-Al₂O₃catalyst modified with P also has a remarkable catalytic activity for themethanolysis reaction of sodium borohydride. Both the spontaneous and catalyticmethanolysis reaction of NaBH4were found to follow first-order kinetics withrespect to NaBH4concentration during0and40℃.