Spillover hydrogen has been shown to contribute to gas phase aromatic hydrodechlorination and hydrogenation over Ni/SiO2 + SiO2 physical mixtures. The reaction rates (per unit mass Ni) are enhanced by extending the Ni/SiO2-SiO2 interface; a non-contiguous combination does not deliver any beneficial effect. The physical mixtures exhibited different selectivity trends for the conversion of 1,3,5-trichlorobenzene and served to prolong productive catalyst lifetime by inhibiting coke formation.