Promotion of Sn on the Pd/AC catalyst for the selective hydrogenation of cinnamaldehyde

• PdSn type alloy NPs were prepared on AC support;
• Catalysts with PdSn type alloy NPs gave excellent selectivity toward CAL selective hydrogenation;
• The favorable adsorption of C = O bond on the uniform PdSn type alloy has been supported by means of DFT.

The effect of Sn on the Pd/AC catalysts for the selective hydrogenation of cinnamaldehyde (CALD) was investigated. TEM, EDX, XRD and XPS have been employed to characterize Pd–Sn/AC. 80% cinnamyl alcohol (COL) selectivity can be obtained at 96% CALD conversion, even 100% selectivity can be achieved at 3% conversion. The PdSn type alloy is responsible for the enhancement of unsaturated alcohol (UA) selectivity, as confirmed by XRD and EDX. XPS technique confirmed that the promoting effect of Sn was related to Pd–Sn interaction. The favorable adsorption of C = O bond on the PdSn has been supported by means of density functional theory.