A facile synthesis of high activity cube-like Pt/carbon composites for fuel cell application

Abstract

High activity catalyst with simple low-cost synthesis is essential for fuel cell commercialization. In this study, a facile procedure for the synthesis of cube-like Pt nanoparticle (Pt_Cube) composites with high surface area carbon supports is developed by mixing precursor of Pt with carbon supports in organic batches, hence, one pot synthesis. The Pt_Cube grow with Vulcan XC-72 or Ketjen black, respectively, and then treated for 5.5 h at 185ºC (i.e., Pt_Cube5.5/V and Pt_Cube5.5/K). The resulting particle sizes and shapes are similar; however, Pt_Cube5.5/K has a larger electrochemical active surface area (EASA) and a remarkably better formic acid (FA) oxidation performance. Optimization of the Pt_Cube/K composites leads to Pt_Cube10/K that has been treated for 10 h at 185ºC. With a larger EASA, Pt_Cube10/K is also more active in FA oxidation than the other Pt_Cube/K composites. Impedance spectroscopy analysis of the temperature treated and as-prepared (i.e., untreated) Pt_Cube/K composites indicates that Pt_Cube10/K is less resistive, and has the highest limiting capacitance among the Pt_Cube/K electrodes. Consistently, the voltammetric EASA is the largest for Pt_Cube10/K. Furthermore, Pt_Cube10/K is compared with two commercial Pt/C catalysts, Tanaka Kikinzoku Kogyo (TKK), and Johnson Matthey (JM)Pt/C catalysts. The TKK Pt/C has a higher EASA than Pt_Cube10/K, as expected from their relative particles sizes (3–4 nm vs. 6–7 nm for Pt_Cube10/K), however, Pt_Cube10/K has a significantly better FA oxidation activity.

Keywords

synthesis / cube-like Pt / Pt/C composite / catalyst / impedance

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg