Nanostructured Pd/C catalysts prepared by grafting of model carboxylate complexes onto functionalized carbon

Pd(5 wt%)/C catalysts were prepared by grafting carboxylate precursors onto functionalized carbon. The functionalization of the support was carried out with HNO3 or H2O2, and the number and nature of oxygenated functions introduced were determined by a combination of simplified Boehmʹs titration, XPS, BET, and DRIFTS. These functions were then used as anchors for model Pd precursors through covalent bonding. The underlying ligand-exchange mechanism was elucidated through detailed XPS studies. The thermal activation of the grafted materials was followed by in situ mass spectrometry, which demonstrated that it consisted of ligand losses. The activated samples were characterized by SEM, XRD, CO chemisorption, and XPS and used in the reduction of 2-methyl-2-nitropropane (MNP) into t-butylamine (TBA). The catalytic activity was shown to be correlated with the initial carbon acidity and the Pd dispersion.