Restructuring of supported PtSn bimetallic catalysts during aqueous phase oxidation of 1,6-hexanediol

• Pt–SnOx interface moderately promotes the activity of 1,6-hexanediol oxidation.
• Treatment of Pt–SnOx in H2 at 673 K forms Pt–Sn alloy nanoparticles.
• Alloyed Pt–Sn nanoparticles are less active than Pt for 1,6-hexanediol oxidation.
• De-alloying of Pt–Sn nanoparticles occurs during reaction.

A series of carbon-supported bimetallic PtSn catalysts having various Pt/Sn molar ratios was prepared and tested in the oxidation of 1,6-hexanediol with 1 MPa dioxygen at 343 K in aqueous solvent. The PtSn/C catalysts, which were initially reduced with sodium borohydride, did not produce Pt–Sn alloy particles. Instead, the catalysts were composed of SnOx moieties that were well-dispersed on the surfaces of the carbon support and the Pt nanoparticles. Subsequent treatment in H2 at 673 K induced Pt–Sn alloy formation. Whereas addition of SnOx to the Pt nanoparticles promoted the initial 1,6-hexanediol oxidation rate by 39%, the formation of Pt–Sn alloy particles decreased the initial rate. Under 1,6-hexanediol oxidation conditions, however, the Pt–Sn alloy phase separated, leading to the recovery of the catalytic activity. No significant change of product distribution was observed on bimetallic PtSn catalysts, regardless of the composition and structure.

Figure optionsDownload high-quality image (83 K)Download as PowerPoint slide