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Summary The development of highly active and cost effective catalysts for hydrolysis of sodium borohydride (NaBH4) is the main aim for practical usage of NaBH4 for fuel cells. Herein, we investigated the addition of various amounts of Triton during chemical reduction process on the NiB catalytic activity. The experimental results indicated that the catalytic performance of Triton stabilized NiB catalysts was significantly higher than that of NiB catalysts. Furthermore, the highest hydrogen generation rate in NaBH4 hydrolysis was obtained with 25 μL Triton addition as 8970 mL.min−1.g−1cat at 338 K. The activation energy of the hydrolysis for NiB25 and NiB catalysts were calculated as 48.05 and 58.91 kJ mol−1, respectively. In the second part of this study, the kinetic performance of NaBH4 hydrolysis was experimentally studied, and subsequently generated hydrogen from the hydrolysis reaction was fed directly to the fuel cell and the performance analysis were investigated. It was found that the power density of pure hydrogen was lower than the hydrogen generated by the NiB25 catalysts. Our results clearly indicated that Triton possessed a significant effect on the catalytic activity of NiB catalyst. [ABSTRACT FROM AUTHOR]

NaBH with catalytic amounts of NiB as an additive reagent reduced aromatic and aliphatic nitro compounds to the corresponding amines in high to excellent yields. Reduction reactions were carried out in HO within 3-30 min at room temperature or 75-80 °C. The catalytic activity of NiB as an additive reagent was superior to using the in situ precipitated one. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] NiB, PVP-NiB and PVP-NiB/SiO2 catalysts were prepared with chemical reduction. [•] PVP-NiB/SiO2 catalysts with amorphous alloy structure, high B content and larger S BET were obtained. [•] PVP-NiB/SiO2 could improve the cleavage of bridge bonds and the hydrogenation of aromatic rings and unsaturated bond. [•] The electrolytic yield of coal with PVP-NiB/SiO2 catalyst could reach up to 57%. [ABSTRACT FROM AUTHOR]

Abstract: Surfactant-stabilized NiB catalysts (ME-NiB) were prepared using the chemical reduction method in the ternary microemulsion system of water/cetyl-trimethyl-ammonium bromide (CTAB)/n-hexanol. The surfactant molecules could adsorb onto the surface of the formed particles, and acted as a protective agent to stabilize and restrict the growth of particles. The size of the nanoparticles was not fully determined by the size of the microemulsion droplets, which depended on the composition of the microemulsion system. Additionally, the particle sizes and the reactivities of the ME-NiB nanoparticles depended on the concentration of nickel salt, the amount and speed of addition of NaBH4 and the temperature. The ME-NiB samples were characterized by X-ray diffraction (XRD) as an amorphous structure and by transmission electron microscopy (TEM) as having particle size distributions in the range 3–8nm, which was much smaller than that of NiB (20–50nm) prepared by the typical chemical reduction method. The ultrafine catalyst of ME-NiB was markedly more active than NiB in the hydrogenation of carbonyl and olefinic groups. A good yield of citronellal/citronellol was obtained from the selective hydrogenation of citral at a low temperature of 30°C over the ME-NiB catalyst. [Copyright &y& Elsevier]

A series of NiP xB y nanomaterials were prepared by a chemical reduction method under various preparation parameters. Experiment results show that the different preparation parameters affected the morphology, particle size, surface area and the composition of the sample. However, they did not influence the electronic state of nickel. The type of solution showed significant influence on the properties of the sample, whereas, the type of nickel salt did not. The particle size of NiPB, NiB, and NiP were 10–30 nm. The NiP sample prepared in the aqueous solution had the largest particle size 50–150 nm. If the solvent was 50% ethanol in water, the surface area of the sample significantly increased nine fold for NiP and four fold for NiPB powders. In contrast, the surface area of NiB did not increase. The NiPB, NiB, and NiP powders had a spherical morphology if they were prepared with aqueous solution. The NiPB prepared in 50% ethanol solution showed floss morphology and had a very high surface area. [ABSTRACT FROM AUTHOR]