On the promoting effect of Au on CO oxidation kinetics of Au–Pt bimetallic nanoparticles supported on SiO2: An electronic effect?

Bimetallic AuPt nanoparticles prepared by radiolysis with Au/Pt atomic ratios of 1.2 and 1.8 were deposited onto silica and calcined to remove the stabilizing polymers. During this sequence, they lose their core–shell structure and restructure as alloys. FTIR and XPS provide evidence for further AuPt NP restructuring under CO exposure and CO oxidation with Pt surface enrichment. A promoting effect of Au is found on the CO oxidation kinetics in the AuPt catalyst with the lower Au/Pt ratio. This effect is attributed to an electron enrichment of the Pt surface atoms due to charge transfer from Au to Pt, as indicated by XPS and CO-FTIR.

A promoting effect of Au is reported on the kinetics of CO oxidation over Pt on AuPt bimetallic nanoparticles supported on SiO2. This is attributed to a greater electron density of the Pt surface atoms due to charge transfer from Au to Pt, as indicated by XPS and CO-FTIR.Figure optionsDownload high-quality image (74 K)Download as PowerPoint slideHighlights
► Supported core–shell AuPt NPs transform into alloys after being thermally treated (not preserved).
► CO-FTIR and XPS provide evidence for AuPt NP restructuring under CO or CO oxidation.
► A promoting effect of Au is found on the CO oxidation kinetics in the AuPt catalyst.
► This effect is attributed to electron enrichment of Pt.