Remarkable hydrodechlorination activity over silica supported nickel/gold catalysts

We compare, for the first time, gas phase catalytic 2,4-dichlorophenol hydrodechlorination (HDC) activity of Ni/SiO2 with a coimpregnated Ni-Au/SiO2 (Ni/Au atomic ratio = 10). The presence of Au lowered the temperature requirements for metal reduction and impacted on H-2 uptake/release. Ni-Au/SiO2 delivered a higher HDC activity and an unprecedented enhancement of HDC performance after thermal treatment. This response is linked, on the basis of TEM-EDX analysis to the creation of surface Ni-Au interactions. This effect did not extend to gas phase phenol hydrogenation where Ni-Au/SiO2 was less active and thermal treatment had no significant effect on activity/selectivity. (c) 2005 Elsevier B.V. All rights reserved.