Influence of Metal Particle Size in Nickel-on-Aerosil Catalysts on Surface Site Distribution, Catalytic Activity, and Selectivity

Pd/Mg(Al)O catalysts obtained from hydrotalcites: investigation of acid–base properties and nature of Pd phases

“…In contrast, the ratio between linearly and bridged bonded species is high for PdMgAlx(ac) samples, as generally observed for polycrystalline Pd systems supported on various oxides [38][39][40][41]. In fact, the relative concentration of linear and bridged CO chemisorption sites is particle-size dependent, the former increasing at the expense of the latter on decreasing the Pd particle sizes [38,39]. This different behavior with respect to Pd single crystals is likely due to the presence of additional crystal facets and of higher amounts of low coordinated sites (terraces, edges, and corners) in polycrystalline systems.…”

“…In contrast, the ratio between linearly and bridged bonded species is high for PdMgAlx(ac) samples, as generally observed for polycrystalline Pd systems supported on various oxides [38][39][40][41]. In fact, the relative concentration of linear and bridged CO chemisorption sites is particle-size dependent, the former increasing at the expense of the latter on decreasing the Pd particle sizes [38,39].…”

Stereoselective Synthesis of Alicylic Amines

“…As the particle size decreases so the activity decreases and if we extrapolate both lines back to zero activity the size of the particle can be estimated to be 0.4 nm (0.27 and 0.45 nm). This is in good agreement with the particle size where face atoms decrease to zero (0.6 nm) [4,5] supporting the concept that the hydrogenation of the aromatic ring takes place on the face atoms. A similar effect has been seen with phenol hydrogenation [6,7] where as particle size decreased the activity of the catalyst also decreased.…”

An infrared spectroscopic study of the adsorption of carbon monoxide on silica-supported copper particles

“…Van Hardeveld and Hartog [1], e.g., demonstrated this with nickel-on-silica catalysts. They found that different sites on the nickel surface gave rise to different absorption bands in the infrared spectrum of adsorbed carbon monoxide.…”