Properties of Pd/SiO2 catalyst doubly promoted with La oxide and Si for acetylene hydrogenation

Pd/SiO2 for acetylene hydrogenation was doubly promoted with La oxide and Si, the latter being selectively deposited on Pd instead of on SiO2. La oxide promoted the ethylene selectivity of the catalyst due to its strong interaction with Pd after the catalyst had been reduced at high temperature, e.g., 500 °C, and Si prevented the migration of La oxide in the catalyst when the reduced catalyst was exposed to air. Consequently, the doubly promoted catalyst showed high ethylene selectivity comparable to that of 500 °C-reduced Pd–La/SiO2 even when the catalyst had been oxidized and subsequently reduced at low temperature, e.g., 300 °C.

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► Si was added to La oxide-promoted Pd/SiO2 as an anchor promoter.
► Added Si effectively suppressed La oxide migration during oxidation.
► Added Si preserved enhanced performance of the high-temperature reduced Pd-La/SiO2.
► Pd-La-Si/SiO2 showed high ethylene selectivity even after low-temperature reduction.