Formic acid electro-oxidation on carbon supported PdxPt1-x (0 ≥ x ≥ 1) nanoparticles synthesized via modified polyol method

Carbon supported nanoparticle catalysts of PdxPt1-x (0 >= x >= 1) were synthesized using a modified polyol method and poly(N-vinyl-2-pyrrolidone) (PVP) as a stabilizer Resulting nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS) cyclic voltammetry (CV) and chronoamperommetry (CA) study for formic acid electro-oxidation Surface composition of the synthesized nanoparticles found from XPS revealed the Pt surface segregation even for the Pd-rich compositions It is suggested that the surface segregation behavior in PdPt nanoparticles supported on carbon may be influenced in addition to the difference in Pd and Pt surface energies by particle size and particle interaction with the support According to CA the carbon supported Pd nanoparticles show the highest initial activity towards formic acid electro-oxidation at the potential of 0 3 V (RHE) due to the promotion of the direct dehydrogenation mechanism However its stability is quite poor resulting in the fast deactivation of the Pd surface Addition of Pt considerably improves the steady-state activity of Pd in 12 h CA experiment CA measurements show that the most active catalyst is Pd-0 Pt-5(0) (5) of 4 nm size which displays narrow size distribution and Pd to Pt surface atomic ratio of 27-73 (C) 2010 Elsevier Ltd All rights reserved