Liquid phase hydrodechlorination of chlorinated aromatics at lower temperature on highly defective Pd sites

摘要

Pd catalyst supported on ordered mesoporous silica-carbon nanocomposites (Pd/MSC) was used in hydrodechlorination (HDC) of chlorinated phenol and aromatics at low temperature. Characterization of XRD, XPS, HRTEM and H-2-TPD shows Pd nanoparticles of 13.4nm at nanocrystal joining areas and edge steps on hybrid support of carbon and silica. A large amount of reactive H species exists on Pd/MSC, which exhibits high activity for HDC of chlorinated aromatics at a lower temperature under normal hydrogen pressure. At 258K, the TOFs for 4-chlorophenol and chlorobenzene are 26.3 and 49.6min(-1), respectively. Using triethylamine as a probe, the HDC of chlorophenols was promoted by reactive H species through the formation of sigma-complex of Pd with chlorophenols.