Highly selective hydrodechlorination of CCl4 into CHCl3 on Ag–Pd/carbon catalysts

A series of Ag–Pd/C catalysts with different Ag/Pd molar ratios were prepared by impregnation and characterized by N2 adsorption and XPS. The catalytic performance was investigated in the hydrodechlorination of carbon tetrachloride into chloroform. High selectivity toward chloroform, near 100%, was obtained over Ag–Pd/C bi-metal catalysts. A very pronounced surface enrichment with Ag in Ag–Pd/C catalysts determined by XPS may be responsible for the high selectivity of chloroform. It is suggested that hydrodechlorination of carbon tetrachloride into chloroform occurs on the surface of Ag in the Ag–Pd alloy and the role of Pd is to supply H atoms necessary.