Synthesis and characterization of Co-La-Zr-B quaternary amorphous nano alloy: Kinetic study for hydrogen generation from hydrolysis of sodium borohydride

摘要

Co-La-Zr-B quaternary amorphous nano alloy was for the first time prepared in situ ultrasound-assisted reduction of Co(II), La(III) and Zr(IV) chloride by sodium borohydride aqueous solution. Obtained powder was characterized by XRD, BET, ICP, FE-SEM and TEM techniques. No distinct peak could be observed in XRD pattern of the obtained alloy indicating that the Co-La-Zr-B possessed amorphous structure. Regarding to the size, SEM and TEM images depict that the most of particles are lower than 10 nm and there is no significant aggregation. Co-La-Zr-B nano alloy 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 = 60.06 -kJ mol~(-1)) and effects of the catalyst dosage, amount of substrate, and temperature on the rate for the catalytic hydrolysis of sodium borohydride. Catalytic hydrolysis of NaBH_4 is first order with respect to the catalyst concentration and zero order respect to the NaBH_4 concentration in the case of Co-La-Zr-B quaternary amorphous nano alloy.