Development of styrene divinyle benzene and alumina supported catalyst for hydrogen production from ammonia borane in liquid phase

As chemical hydrogen storage material, especially with high hydrogen capacity (mass ratio %19,6 H2) and high stability in aqueous solutions, ammonia borane (AB; NH3BH3) attracts a great deal of attention recently. In this study, the catalytic hydrolysis in heterogen phase of AB was performed to produce hydrogen from AB with high efficiency at lower temperatures. Experimental studies were conducted in three stages as follows; synthesize of catalyst, parametric reactions experiments and determining the kinetic parameters. Catalysts were prepared with impregnation and cation exchange techniques in this study where were chosen SDVB and Al2O3 as supporting material and Pt, Ru, Co, Cs, Sn as active material. Some characteristic specifications of synthesized catalyst were determined and seen that active materials the surface of support material by dispersing homogenously in nano-scale. In the second stage of study, the effects of initial concentration, amount of catalyst and temperature on hydrogen production from AB were investigated and the percent efficiency values of hydrogen productions for each catalyst were recorded at the end of the experiment. Results point out that, %1Pt/Al2O3, %1Ru/Al2O3, %2Sn/SDVB and %2Cs/SDVB catalysts at 50 C were determined catalyst with the highest performance by showing hydrogen production efficiencies of 87%, 84,4%, 84,4%, 84,4% respectively. It was also observed that Cs and Sn had high performance in SDVB support material but low in Al2O3. At the last stage, exponential kinetic for the expression of the observed reaction rate was presented and determined that %5Co/Al2O3 catalyst is zero order with respect to AB and the other catalysts are the first order. In addition, the result point out that there is a linear relation between the amount of catalyst in Pt, Ru, and Co catalysts and the reaction rate constant and the initial concentration of AB had no effect on catalyst of Ru and Co at 40 C but effective on Pt catalyst. For all catalysts, activation energies were determined and for %1Pt/Al2O3, %1Ru/Al2O3, %2Sn/SDVB and %2Cs/SDVB catalysts, activation energies were calculated as 32, 29, 30, 31 kj/mol respectively.