Composite Catalysts Of Pt-Co Alloy Prepared By Electrodeposition And Their Application To DMFC

Direct methanol fuel cells (DMFCs) are widely applied in transportation and in portable electronic devices because they are low-pollution and high efficiency cells which can be operated under room temperature. Although DMFCs are considered as one of the best energy conversion devices, their commercial applications are confined by the low catalytic activity and high cost of the anodic electrocatalysts. This article focused on the preparation of Pt-Co electrocatalysts with high catalytic activity by adding certain amount of electrolytes onto the carbon paper and CNT/carbon paper then using pulse current electrodeposition. The influences of particle sizes and dispersion to the electrocatalytic activity for methanol oxidation were analyzed by cycle voltammetry (CV), X-ray diffraction (XRD) and scanning electron microscope (SEM). The Pt-Co/CNT electrocatalysts were assembled to membrane electrode assembly (MEA) and single cell. The discharge properties were further evaluated.Pt-Co/carbon paper electrocatalysts were synthesized by pulse current electrodeposition using carbon paper as supporting material. The influences of experiment conditions, such as current density and concentrations of precursors to the particle sizes and dispersion were further studied. The results indicated that Pt-Co/carbon paper electrocatalysts with best electroactivity and anti-poisoning ability were obtained at peak current density of 500 mA·cm-2 with Pt and Co precursor's ratio of 1:1.Pt-Co/CNT electrocatalysts were synthesized by pulse current electrodeposition using Nafion-bonded CNTs as supporting material. The influences of experiment conditions, such as preparation methods of Nafion-bonded CNTs, electrodeposition conditions and concentrations of precursors to the particle sizes were further studied. The results indicated that Pt-Co/CNT electrocatalysts with best electroactivity and anti-poisoning ability were obtained at peak current density of 50 mA/cm2 with pulse on-time as 10 ms and pulse off-time as 30 ms on NBC with 2.0 mg/cm2 CNTs and 30.0 wt.% Nafion with Pt and Co precursor's ratio of 1:1.