Study of CO chemisorption on graphite-supported Ru–Cu and Ni–Cu bimetallic catalysts

Modification of catalytic properties over carbon supported Ru–Cu and Ni–Cu bimetallics

“…The reason for this later effect is probably due to the fact that at such high values of Cu content, there is sintering of part of the Cu particles which are no longer decorating the surface of the Ru particles but are forming separate particles. This is in agreement with the results obtained when microcalorimetric studies were carried out on these same catalysts [28] and it was said that in the catalysts with lower Cu content Cu was decorating the Ru surface.…”

“…This only confirms our results obtained with these catalysts employing microcalorimetric technique, where the decrease in heat of adsorption with increasing Cu content gave us hints on the interaction between Ni and Cu particles due to alloy formation [28].…”

“…As Cu was introduced and increased along the series, there was an increase in the binding energy of the Ni 0 as well as of the Ni 0 /Ni 2+ ratio (from about 0.2 to 1). Like the Ru-Cu catalysts, this series was also studied by the microcalorimetric technique and in this case alloy formation was observed [28]. Therefore, this increase in binding energy (from 852.6 to 854.5 eV) is due to a decrease in electron density of Ni aggregates caused by the interaction between Ni and Cu particles which results in a decrease in the ensemble size of the Ni particles (which will give rise to lower electron density of this ensemble).…”

“…We shall characterize these catalysts with the aid of hydrogen chemisorption measurements, temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). Microcalorimetry of the CO adsorption on the metal aggregates was carried out on both series [28] in order to study the interaction between the metallic elements. These catalysts will be applied in two hydrogenation reactions so as to observe the selectivity tendencies in both cases which strongly depends on the Cu content in each of the catalysts belonging to the series and on the difference in interaction between the two elements that exists in both series.…”

Synthesis of highly thermostable copper-nickel nanoparticles confined in the channels of ordered mesoporous SBA-15 silica

“…by ensemble and/or electronic effects). [47][48][49][50] Few studies on supported CuNi/SBA-15 catalysts prepared by IWI have been reported. 29,30,36,42 However, the effect of thermal conditions during calcination and reduction on the dispersion and stability of oxidic and catalytic metallic phases has not been specifically investigated.…”