Electrochemical characterization of Pt–Ru–Ni/C anode electrocatalyst for methanol electrooxidation in membraneless fuel cells

Abstract

In the present work, carbon-supported Pt–Ru, Pt–Ni and Pt–Ru–Ni electrocatalysts with different atomic ratios were synthesized by NaBH₄ reduction method. The synthesized electrocatalysts were characterized by TEM, EDX and XRD analyses. The Pt metal was the predominant material in all the samples, with peaks attributed to the face-centered cubic (fcc) crystalline structure. The TEM analysis indicated that the prepared catalysts had similar particle morphology, and their particle sizes were 3–5 nm. The electrocatalytic activities of the synthesized electrocatalysts were characterized by cyclic voltammetry (CV) and chronoamperometry (CA). During the experiments performed on single membraneless fuel cells, Pt₅₀Ru₄₀Ni₁₀/C performed better among all the catalysts prepared with power density of 38.2 mW cm⁻². The enhanced methanol oxidation activity by Ni in Pt₅₀Ru₄₀Ni₁₀/C can be attributed to the electronic effect as the result of the modification of electronic properties of Pt and the various oxidation states of Ni. In this work, for the first-time carbon-supported binary Pt–Ru, Pt–Ni and ternary Pt–Ru–Ni anode catalysts were successfully tested in a single membraneless fuel cell using 1.0 M methanol as the fuel and 0.1 M sodium perborate as the oxidant in the presence of 0.5 M H₂SO₄ as the electrolyte at room temperature.