Microfibrous-Structured Pd/AlOOH/Al-Fiber with Hydroxyl-Enriched Surfaces for the Catalytic Semihydrogenation of Acetylene

Thin-sheet Al-fiber-felt-structured Pd/AlOOH/Al-fiber catalysts are developed for the back-end process of semihydrogenation of acetylene. A series of AlOOH/Al-fiber substrates were synthesized by endogenous growth and subsequent annealing in air. Palladium was then dispersed onto the as-obtained substrates by impregnation. The catalyst activity and stability show interesting substrate annealing temperature dependence. The preferred catalyst, obtained by dispersing lower than 0.05 wt % Pd onto the AlOOH/Al-fiber annealed at 100 °C, exhibits a high specific activity with the turnover frequency (measured at 40 °C) of 0.0167 s–1, being two times as high as that (0.0083 s–1) for the catalyst using a high substrate annealing temperature of 600 °C. Low AlOOH/Al-fiber annealing temperature enables the catalysts with hydroxyl-rich surfaces that not only promote the hydrogen activation on Pd but also strengthen the adsorption of acetylene. Notably, the Pd–hydroxyl interaction obviously suppresses carbonaceous deposition, thereby getting the stability improved by a large extent.