Deactivation behavior of a TiO₂-added Pd catalyst in acetylene hydrogenation

The deactivation behavior of a TiO₂-added Pd catalyst, reduced at 773 K, for the selective hydrogenation of acetylene showed that the added TiO₂ suppressed the formation of green oil and, consequently, improved the lifetime of the catalyst. The average number of carbon atoms per green oil molecule was smaller for the TiO₂-added catalyst than for the Pd-only catalyst because multiply coordinated Pd sites were suppressed on the TiO₂-added catalyst. The added TiO₂ also retarded the sintering of Pd particles during catalyst regeneration, presumably due to the anchoring effect of TiO₂, and suppressed green oil formation, even after the regeneration step.