Enhanced performance for proton conducting fuel cells at low temperature

A platinum-cobalt-iron ternary alloy is deposited on a TiO₂─ coated multi-walled carbon nanotube support (PtCoFe/MWCNT─TiO₂) using a two-step hydrothermal method and evaluated as an anode catalyst for direct methanol fuel cells. Catalysts with different weight ratios of Pt:Co:Fe (3:1:1, 1:1:1 and 1:3:3) on MWCNT─TiO₂ are prepared and examined. The Pt₃Co₁Fe₁/MWCNT─TiO₂ catalyst shows higher catalytic activity and stability compared to the 1:1:1 and 1:3:3 catalysts for the methanol oxidation reaction in acidic media. Cyclic voltammetry analysis shows a maximum mass activity for Pt₃Co₁Fe₁/MWCNT─TiO₂ of 4.17 A mg⁻¹_Pt (vs. Ag/AgCl) with a low onset potential in 0.4 M H₂SO₄ and 0.3 M CH₃OH solution. A single fuel cell based on Pt₃Co₁Fe₁/MWCNT─TiO₂ anode catalyst exhibits a maximum power density of 117.94 mW cm⁻² at 50 °C in 1.3 M CH₃OH, which is significantly higher than that of the Pt₁Co₁Fe₁/MWCNT─TiO₂, Pt₁Co₃Fe₃/MWCNT─TiO₂, and Pt/MWCNT catalysts.