Gas-phase hydrogenation of acetonitrile over Pt and Pt-Pd supported on mesoporous solids: influence of the metallic precursor

Gas-phase hydrogenation of acetonitrile has been chosen as a test reaction to evaluate the catalytic behaviour of supported bimetallic catalysts prepared from dinuclear complexes precursors. Thus, Pd/Pt supported on zirconium doped mesoporous silica catalysts, with total metal loading of 1 and 2 wt.%, have been obtained by incipient wetness impregnation by using [PdPtCl2(μ-dppm)2], after removing the ligands by calcination and subsequent reduction with H2. These catalysts have been compared with supported platinum or palladium/platinum catalysts with similar metal loadings prepared from classical inorganic salts ([Pt(NH3)4](NO3)2, PdCl2 and H2PtCl6·6H2O). The metal-based catalysts have been characterized by powder XRD, adsorption-desorption of N2 at 77 K, TEM, H2-TPR and NH3-TPD. A remarkable high degree of metal dispersion was attained when using the dinuclear precursor, giving rise to the highest yield of triethylamine in the gas-phase hydrogenation of acetonitrile, with a selectivity toward this tertiary amine close to 100%.