Bismuth modified Au-Pt bimetallic catalysts for dihydroxyacetone production

•Carbon supported AuPt alloyed NPs were modified by different amount of Bi.•The catalysts were active in glycerol base-free oxidation.•Selectivity depends on the presence of Bi modifier which is able to direct the reaction toward the production of dihydroxyacetone, an important chemical.•Bi-AuPt/AC catalyst showed an improved stability in terms of both activity and selectivity with respect to commercial Bi-Pt/AC.

Bi has been employed as a modifier for AuPt/AC alloy based catalysts for the base-free glycerol oxidation. The addition of Bi has a significant effect on the selectivity of the reaction. Indeed, in the absence of Bi, the oxidation of the primary alcohol function is favored with the production of glyceric acid as main product. On the contrary, the addition of Bi promotes the oxidation of the secondary OH function leading to the production of dihydroxyacetone (DHA) as the main product (selectivity of 63% at 80% conversion). Differently from the gold-free catalyst Bi-Pt/AC, which suffers from Bi leaching, the Au modified one, namely Bi-AuPt/AC, enhances the catalyst stability by limiting the Bi leaching thus resulting in a good selectivity to DHA even at high conversion.

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