Fabrication of BixPtyPdz alloy nanoporous plates with electro-catalytic activity

Abstract

We demonstrate the fabrication of Bi₂₁Pt₃₅Pd₄₄ alloy porous nanoplates by a galvanic replacement method using Bi₆₅Pt₃₅ bimetallic nanoplates as the sacrificial template. Bi₆₅Pt₃₅ nanoplates, prepared by reduction with diol (1,2-hexadecanediol) at low temperature (100 °C), were converted to the porous nanoplate structure by a K₂PdCl₄/water/ethanol (1/1, v/v) mixed solution via galvanic replacement between bismuth and palladium. The formation of Bi₂₁Pt₃₅Pd₄₄ porous nanoplates is attributed to disperse crystallization under conditions of high nucleation rate. The electro-chemically active surface area (ECSA) for the Bi₂₁Pt₃₅Pd₄₄ alloy porous nanoplate is measured to be 0.943 cm². This value is 3 times greater than the ECSA (0.283 cm²) of the commercial Pt/C (Alpha, Pt 20%) electrode. The electro-catalytic activity of the prepared porous nanoplates was examined for the oxidation of methanol in acidic solution. The Bi₂₁Pt₃₅Pd₄₄ porous nanoplates can effectively catalyze oxidation of methanol in acidic solution, probably owing to their larger surface area and many active reaction sites. The Bi₂₁Pt₃₅Pd₄₄ porous nanoplates provide a new form of unsupported catalysts in contrast to the traditional supported nanoparticle catalyst and can be uniformly synthesized and separated easily from the reaction mixtures without aggregation.