Pt−Co Bimetallic Catalyst Supported on Single-Walled Carbon Nanotubes: Effect of Alloy Formation and Oxygen Containing Groups

Pt monometallic and Pt−Co bimetallic catalysts have been prepared on single-walled carbon nanotubes (SWNT) with and without HNO 3 treatment. The HNO 3 treatment introduced oxygen containing groups (OCGs), which affect both the structure and activity of the catalyst. The introduction of OCGs does not affect the structure of Pt monometallic catalysts but increased the dispersion in the bimetallic catalysts. The aqueous phase re-forming (APR) activity of the bimetallic catalysts is also affected by the OCGs, because the local concentration of the reactant around the SWNT support with OCGs is less than the case without OCGs. The two effects act on activity in opposing directions so the bimetallic catalysts on the two supports give similar APR yields, but this discovery gives us direction and a basis for the future design and improvement of SWNT supported catalysts.