“…The strong interaction of Pd and the surface p sites of C-A and C-AN was previously shown to lead to modification of the chemical properties of Pd [33]. Two adsorption configurations of phenol on Pd are known [34]: one is r-adsorption via oxygen, and the other is p complexation via the aromatic ring. For both configurations, phenol adsorption on Pd is weakened if the electron density of Pd is increased.…”
The influence of the acid treatment on cyclohexanone selectivity of phenol hydrogenation over Pd on active carbon was studied in liquid phase reaction and by temperature-programmed desorption. Acid treatment of activated carbon led to an increased cyclohexanone/cyclohexanol ratio. Acid modification of the carbon support enriched the electron density of Pd, and enhanced the desorption of the phenoxy species, which resulted in improved cyclohexanone selectivity in phenol hydrogenation.
“…The strong interaction of Pd and the surface p sites of C-A and C-AN was previously shown to lead to modification of the chemical properties of Pd [33]. Two adsorption configurations of phenol on Pd are known [34]: one is r-adsorption via oxygen, and the other is p complexation via the aromatic ring. For both configurations, phenol adsorption on Pd is weakened if the electron density of Pd is increased.…”
The influence of the acid treatment on cyclohexanone selectivity of phenol hydrogenation over Pd on active carbon was studied in liquid phase reaction and by temperature-programmed desorption. Acid treatment of activated carbon led to an increased cyclohexanone/cyclohexanol ratio. Acid modification of the carbon support enriched the electron density of Pd, and enhanced the desorption of the phenoxy species, which resulted in improved cyclohexanone selectivity in phenol hydrogenation.
“…By analogy with phenol, the fate of the chlorophenol molecule upon chemisorption on metallic surfaces is believed to involve O-H bond fission (its weakest bond) and the resulting formation of a surface phenoxy species [108][109][110]. In a DFT study which used a single CuO dimer to represent a CuO surface it was found that the formation of 2-chlorophenoxy from O-H fission in the 2-chlorophenol molecule was rendered facile by the CuO dimer and the overall process was significantly exothermic, in contrast to the uncatalyzed gaseous process [111].…”
Section: Catalytic Formation Of Pcdd/fs From Precursorsmentioning
“…Possible C-derived orbitals (if any) cannot be identified, partly due to their weak cross sections in He I and their overlap with OH, partly due to the three-dimensional character of the carbonaceous overlayer [6] which shields the Pt-C bands from detection. Very weak carbon signals were reported for a residual carbonaceous overlayer after annealing adsorbed aromatic adlayers [18]. Individual UP spectral features have their counterparts in the O ls XP spectral region (compare figs.…”
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