Tailoring supported palladium sulfide catalysts through H2-assisted sulfidation with H2S

Supported palladium sulfide catalysts are of great interest in selective hydrogenation reactions. In this work, “Pd4S”, “Pd3S”, “Pd16S7” and “PdS” supported on activated carbon were selectively synthesized by tailoring the H2-assisted sulfidation of Pd/C with H2S at 150–750 °C, and were characterized by means of XRD, XPS, TEM, HRTEM, EDS, BET and H2-TPR techniques. The results indicated that the sulfidation atmosphere, the sulfidation temperature and the metal–support interaction all played important roles in determining the crystal structure and composition of the PdxSy/C catalysts, which in turn gave different catalytic performances in the synthesis of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) by the reductive N-alkylation of aromatic amines. PdS/C showed the highest selectivity (>97%) and stability among all the PdxSy/C catalysts.