Investigation of carbon and alumina supported Pd catalysts during catalyst preparation

The preparation by a deposition-precipitation method (using Na2PdCl4 as palladium precursor and Na2CO3 as basic agent) of Pd catalysts supported on γ-Al2O3 and on two different types of activated carbons has been studied by EXAFS and TPR as a function of Pd loading from 0.5 to 5.0 wt%. Independently from the support, neither reduced metal fraction nor crystalline phase has been observed. EXAFS shows that the Pd local environment of the final catalysts changes slightly as a function of the Pd loading from 0.5 to 2.0 wt%: at higher loadings no further modification has been observed.