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

Abstract

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 Pd_xS_y/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 Pd_xS_y/C catalysts.