Synthesis And Performance Study Of Nanocatalysts Toward Hydrogen Decomposition From Novel Chemical Hydrogen-storage Material

This thesis mainly studies the catalysts for hydrolytic dehydrogenation of ammoniaborane—the novel chemical hydrogen storage material, including the designing, synthesis,characterization and application of the catalysts. The main achievements are outlined asfollowing：First, in consideration of the advantages of noble metal as catalysts, the in situ preparednoble nanocatalysts were studied. As the result, Pt was screened out as the potential catalystfor catalytic dehydrogenation of ammonia borane. In addition, to obtain well-dispersed Ptnanocatalysts, the surfactant was added during the synthetic process, resulting in the enhancedcatalytic activity (7.5min, Pt/AB=1/100).Then, the polyol reduction method was adopted to prepare active carbon supported Ptnanoparticles with high dispersity, which possessed small dimension (mean particle size:2.19nm) and narrow size distribution. Compared with Pt/C catalyst synthesized by commonlyused impregnation-NaBH4reduction process， the as-prepared catalyst exerted superiorcatalytic activity toward hydrolytic dehydrogenation of ammonia borane (6min,Pt/AB=1/200). Furthermore, the detailed factors affecting the activity were also concerned.Next, for the purpose of preparing Pt nanoparticles with extremely small size, narrowsize distribution and high dispersity, the unique photo-induced reduction process was appliedto synthesize graphene supported Pt nanocatalyst. The mean size of the obtained Ptnanoparticles was only1.41nm, rendering the catalyst with high active surface area. Theas-prepared catalyst not only reduces the dosage of Pt, but also gives full play to the catalyticefficacy (18.3min, Pt/AB=1/1000).Finally, taking advantage of the different reduction potential between noble andnon-noble metals, ammonia borane was used to in situ synthesize graphene supported Pd@Cocore-shell nanocatalyst. It was proven that the cooperative synergetic effect between grapheneand nanostructures facilitated ammonia borane decomposition [3.5min,(Pd0.1Co0.9)/AB=1/50]. Combined with the merits of low-cost and magnetically recyclability,the as-synthesized catalyst had the capability of practical application.