Effect of metal alloying on morphology and catalytic activity of platinum-based nanostructured thin films in methanol oxidation reaction

Abstract

Direct methanol fuel cells are considered to be promising sources of green power. However, their commercialization is seriously hindered by the high cost of Pt. The use of an alloy is an effective way to solve the problem. According to Duan and Lee et al., nanosheets and nanobranches (similar to dendrimers) are highly favored for superior catalytic performances due to their geometric properties. In this paper a facile and efficient approach for the synthesis of binary, ternary and tetrametallic alloy thin films at a liquid–liquid interface was demonstrated. Transmission electron microscopy exhibited a nanodendritic structure for PtPdNiFeFe₂O₃, a nanosheet structure for PtPdNi or PtPdNiZn, and spherical nanostructures for PdNi, PtNi and PtPdNiSn alloy thin films. The synthesized PtPdNiFeFe₂O₃ nanodendrimers, and PtPdNiZn and PtPdNi alloy nanosheets exhibit a higher electrocatalytic activity toward methanol oxidation than other binary alloy thin films such as a PdNi thin film, and monometallic Pt or Pd thin films which may be attributed to their large surface area. Due to simple implementation, the proposed approach can be considered as a general and powerful strategy to synthesize ternary and tetrametallic alloy electrocatalysts with high surface area.