Unsupported Ni(Pt‐Pd) Electro‐catalysts Synthesized by Hydrazine Reduction under the Assistance of a Magnetic Field

Abstract

AbstractThe synthesis of unsupported Ni(Pt−Pd) catalysts via a two‐step process under the assistance of a magnetic field in the presence and absence of sodium citrate was investigated. In absence of the complex agent, sandspur‐like (Ni‐SS(PtPd)) particles of about 90 nm with thorns of ca. 40 nm in length were obtained, while in the presence of citrate anion the catalyst showed the occurrence of nanowires (Ni‐NW(PtPd)), with lengths in the range of 1–10 μm formed by grains of about 45 nm in size. The catalysts prepared in‐house were tested for ethanol electro‐oxidation in alkaline medium at room temperature. The activity of Ni‐NW(PtPd) electrode was almost 32 % higher than that of Ni‐SS(PtPd) material, while the poisoning rate was smaller at the same potential range. Hence, considering that both catalysts have practically the same composition, it is interesting to note that Ni‐NW(PtPd), which has the smallest electroactive surface area, is the one that presents the highest activity for the ethanol oxidation reaction (EOR). This result could be attributed to the lattice strain and electronic effects derived from the particle structure and morphology of the particles, and the electron transport rate through the materials.