Adsorption-desorption kinetics of H2 from supported nickel catalysts

Downshift of the Ni d band center over Ni nanoparticles in situ confined within an amorphous silicon nitride matrix

“…Lee et al reported that the higher coverage of hydrogen atoms – the lower E des value of hydrogen atoms – was observed in the Ni/SiO 2 sample ( E des ranging from 89 kJ mol −1 at low coverage to 55 kJ mol −1 at high coverage). 37 Although the coverage of hydrogen atoms onto Ni is low in the Ni/a-Si 3 N 4 sample as shown in Fig. S6,† the E des value is interestingly lower in the Ni/a-Si 3 N 4 sample.…”

Amorphous Ni–B/SiO2 catalyst prepared by microwave heating and its catalytic activityin acrylonitrile hydrogenation

“…The H 2 chemisorption was performed using a dynamic pulsed method. 15 After the sample was purged with an Ar stream (purity 99.99%, deoxygenated by an Alltech Oxy-trap filter) for 1.0 h at 473 K, which was below its crystallization temperature, H 2 pulses were injected at 303 K until the calculated areas of consecutive pulses were constant. According to H 2 chemisorption, the surface active area was calculated by assuming H/Ni (s) = 1 and a surface area of 6.5 × 10 −20 m 2 per Ni atom, based on an average of the area for the (100), (110) and (111) planes.…”

Nickel-embedded zeolite subcrystal catalyst: rapid enhancement of activity and metal impurity resistance in the hydrodesulfurization of 4,6-dimethyldibenzothiophene

“…For instance, noble metals, being heavy elements with high atom volume and polarizability, tend to disperse well in the micropores of zeolites owing to their strong van der Waals interactions with the zeolite pore walls. 8 In contrast, lighter elements such as Ni, which are widely employed in hydrogenation processes because of their exceptional H 2 dissociation and chemisorption capabilities, [9][10][11] face challenges in achieving high dispersion on zeolite supports. 12 Ni species possess a large surface energy and low polarizability, which weaken their interactions with the pore walls of zeolite supports.…”