FT-IR CHARACTERIZATION OF ALKALI-DOPED PD CATALYSTS FOR THE SELECTIVEHYDROGENATION OF PHENOL TO CYCLOHEXANONE

A detailed FT-IR investigation of CO, phenol and cyclohexanone adsorbe d on alkali-doped Pd catalysts has been carried out in order to get in formation on the influence of the support and of the addition of promo ters (alkali or alkaline earth metals) on the catalytic performance of Pd-supported catalysts in the selective hydrogenation of phenol. The obtained results are consistent with a mechanism that involves the rea ction of phenol, adsorbed on the support as a phenolate species, locat ed nearby Pd sites on which hydrogen is activated, The basicity of the support plays an important role in the adsorption of the phenol, Prom oters have been found to modify the electronic properties of the palla dium sites.