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Abstract: Catalyst in the form of Co-B nanoparticles supported on mesoporous silica particles (MSP) was synthesized by chemical impregnation–reduction method. This catalyst powder was used for hydrogen production by hydrolysis of Ammonia Borane (AB) and was compared with Co-B catalyst supported on non-porous silica particles (NSP) and unsupported Co-B powder. It was found that the MSPs synthesized in the present studies have average pore size of about 3.1nm which were efficient to anchor the Co-B particles with average size of ~8nm on the surface to provide high active surface area and improved degree of dispersion. MSP-supported Co-B catalyst was able to produce expected amount of H2 gas from hydrolysis of AB with significantly superior generation rate, about 3 times higher than that produced by unsupported and NSP-supported Co-B catalyst. Availability of a large number of under-coordinated Co active atoms owing to the size of nanoparticles, better dispersion, high surface area and good stability against agglomeration during the reaction are the main features acquired by the Co-B nanoparticles supported on MSP that exhibit high catalytic efficiency. [Copyright &y& Elsevier]

Abstract: Co-P-B catalyst coatings have been synthesized on Ni-foam by using electroless deposition (ED) and their catalytic activity was investigated by catalytic dehydrogenation of ammonia borane (AB, NH3BH3) for H2 generation. Co-P-B catalyst (both in form of powder and coating) showed superior catalytic activity in hydrolysis reaction of AB than that of Co-B powder, with complete evolution of H2 (97%) at very high rate (2l/min/gcatalyst). This was mainly attributed to synergic effect caused by B and P over Co active sites to lower the activation energy of the process. For thermolysis reaction, it was observed that AB loaded on Co-P-B/Ni catalyst releases first mole of H2 at considerably low temperature starting at 50°C and with desorption peak centered at 80°C. To our knowledge this value is the lowest reported for solid state catalyst. Moreover, the catalytic thermolysis did not present any induction time and minimizes the formation of undesirable byproduct like borazine and ammonia. The present result suggests that Co-P-B coated on Ni is a highly efficient and low cost catalyst and can be used for both hydrolysis as well as thermolysis reaction of NH3BH3 with the important advantage that it can be easily recovered and repeatedly reused. [Copyright &y& Elsevier]