Hydrogen Spillover from Ni to CuNi Alloys

Determination of metal particle size of highly dispersed Rh, Ir, and Pt catalysts by hydrogen chemisorption and EXAFS

“…Other, often lower, hydrogen pressures have been used in the literature. According to Crucq et al, the hydrogen adsorption isotherms of supported Pt (49) and Rh 50catalysts are Temkin-like (showing a linear relation between log(P) and H/M over a wide pressure range) due to a strongly decreasing heat of adsorption with coverage. Therefore they recommended the measurement of a single adsorption point at P > 13 kPa at room temperature, to obtain the amount of adsorbed hydrogen close to monolayer coverage.…”

“…Moreover, we feel that the amount of weakly adsorbed hydrogen is difficult to determine objectively, as it depends on the apparatus, pump, and evacuation time used (49). To obtain an idea of the amount of hydrogen which is relatively weakly bound to the metal under our conditions, measurements were done for the 0.81 wt% Ir/A1203 catalyst.…”

Templated synthesis of nickel nanoparticles: Toward heterostructured nanocomposites for efficient hydrogen storage

“…Volumetric and gravimetric hydrogen density of hydrogen storage materials. 9 Hydrogen spillover can occur between a metal and a metal oxide 18 or between two metals 26 and is believed to occur through three principal steps (Scheme 2): (1) Dissociative chemisorption of hydrogen gas on a metal surface, (2) migration of hydrogen atoms to the metal-substrate interface, (3) and diffusion of hydrogen atoms across the metal-substrate interface. 27 Often times, the rate-limiting step and key species in hydrogen spillover are surface diffusion of hydrogen atoms across the metal-substrate interface, or more generally the activator-acceptor interface ( Figure 4).…”

New insights into structure–activity relationships for propane hydrogenolysis over Ni–Cu bimetallic catalysts

“…27 But Cu sites could be possibly occupied by atomic hydrogen by hydrogen spillover from Ni to Cu on bimetallic catalysts, as Crucq et al observed hydrogen spillover from Ni to Cu on Ni-Cu alloys in their hydrogen adsorption isotherms. 28 Recently we got direct evidence that hydrogen spillover from oversaturated Ni sites to Cu sites. 12 As suggested by Goodman and coworkers the possible hydrogen spillover on bimetallic catalysts could results in over counting active sites and failure in the hydrogen selective chemisorptions on bimetallic catalysts.…”