Hydrogen generation from hydrolysis of sodium borohydride by cubic Co-La-Zr-B nano particles as novel catalyst

摘要

Cubic Co-La-Zr-B nano particles were prepared in situ for the first time from the reduction of Co(Ⅱ), La(Ⅲ) and Zr(Ⅳ) chloride by sodium borohydride in methanol under reflux condition. Poly N-vinyl-2-pyrrolidone (PVP) as stabilizing agent was used for preparation of Co-La-Zr-B nano particles. Obtained powders were characterized by XRD, BET, ICP, SEM, TEM and UV-vis techniques. XRD patterns declare that under argon atmosphere only metalboride phase has been crystallized and it was not seen any oxide phase of metals. TEM image depicts that PVP stabilized nano particles are square shaped particles that containing many nanoclusters. Cubic Co-La-Zr-B nano particles were also confirmed by SEM image. Co-La-Zr-B is highly active catalysts for hydrogen generation from the hydrolysis of sodium borohydride. The reported work also includes the full experimental details for the collection of a wealth of kinetic data to determine the activation energy (E_a = 53 kJ mol~(-2)) and effects of the catalyst dosage, amount of NaBH_4, and temperature on the rate of the catalytic hydrolysis of sodium borohydride. Catalytic hydrolysis of NaBH_4 is first order with respect to the catalyst concentration and also first order to the NaBH_4 concentration in the case of cubic Co-La-Zr-B nano particles.