Synthesis of bimetallic SnPt-nanoparticle catalysts for chemoselective hydrogenation of crotonaldehyde: Relationship between SnxPty alloy phase and catalytic performance.

Bimetallic SnPt-nanoparticle (SnPt-NP) catalysts with several types of Sn x Pt y alloy structures were prepared using a polyalcohol reduction process; the catalytic behavior of each Sn x Pt y alloy phase toward the selective hydrogenation of unsaturated aldehydes to the corresponding unsaturated alcohols was elucidated. Atomic absorption spectroscopy (AAS) and transmission electron microscopy (TEM) indicate that SnPt-NP catalysts with various Sn/Pt atomic ratios can be successfully prepared by a polyalcohol reduction process using Pt(acac) 2 and Sn(AcO) 2 as the metal precursors. X-ray diffraction (XRD) results reveal that the Sn 1 Pt 3 , Sn 1 Pt 1 , and Sn 2 Pt 1 alloy phases are formed through control of the Sn/Pt atomic ratio of the starting mixture during preparation. The Sn 1 Pt 3 alloy phase enhanced the hydrogenation of both the C C and C O bonds during the selective hydrogenation of crotonaldehyde. When only Sn 1 Pt 1 alloy phases (Sn/Pt = 1.40), accompanying with separated Sn phase, were formed in the SnPt-NP catalysts, the highest unsaturated alcohol (UOL) selectivity (71.5% at 37.6% conversion) was observed. The formation of the Sn 2 Pt 1 alloy phase led to decreased UOL selectivity. We suggest that the Sn 1 Pt 1 alloy phase is an effective bimetallic SnPt hydrogenation catalyst for the selective formation of unsaturated alcohols. [ABSTRACT FROM AUTHOR]