Performance of Pd–Ag/Al2O3 catalysts prepared by the selective deposition of Ag onto Pd in acetylene hydrogenation

The performance of Ag-promoted Pd/Al2O3 catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed a higher ethylene selectivity than the one prepared by impregnation, because SR allowed both the preferential deposition of Ag on the low-coordination sites of Pd and a greater electronic modification of Pd by Ag.

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► Ag was selectively deposited onto Pd/Al2O3 by a surface redox (SR) method.
► The ethylene selectivity was highly increased when Ag was added by SR.
► Ag was preferentially deposited on the low-coordination Pd sites by SR.
► Pd was more effectively modified by Ag due to intimate Pd–Ag interactions