Effect of Pre-Reduction on the Properties and the Catalytic Activity of Pd/Carbon Catalysts: A Comparison with Pd/Al2O3
The effect of pre-reduction in solution with chemical reagents on the catalytic performance and catalyst properties of Pd/carbon catalysts was systematically investigated with a multitechnique approach. The results are critically discussed in comparison to those recently obtained on analogous Pd/alumina catalysts. It was proved that the Pd phase on the carbon surface is characterized by a high mobility, opposite to what occurs on alumina. As a result, the Pd particles on carbon aggregate together during pre-reduction, with a consequent decrease in available metal surface. Pd particles remain aggregated also in reaction conditions; the decreased Pd dispersion negatively affects the catalyst …
Formation and growth of palladium nanoparticles inside porous poly(4-vinyl-pyridine) monitored by operando techniques: The role of different reducing agents
In this work we followed the formation of palladium nanoparticles, starting from palladium (II) acetate precursor, inside a poly(4-vinylpyridine-co-divinylbenzene) polymer in presence of different reducing agents. The formation and growth of palladium nanoparticles in presence of H-2 was followed as a function of temperature by simultaneous XANES-SAXS techniques, coupled with DRIFT spectroscopy in operando conditions. It was found that the pyridyl functional groups in the polymer plays a fundamental role in the stabilization of the palladium (II) acetate precursor, as well as in the stabilization of the palladium nanoparticles. The effect of a thermal treatment in alcohol (ethanol and 2-pro…