调制脉冲电沉积法制备质子交换膜燃料电池铂催化电极

通过调制脉冲电流在质子交换树脂(Nafion)粘接的无催化多孔碳电极(UCE)上电沉积Pt 催化剂, 对所沉积Pt 催化电极性能及负载量用循环伏安法(CV)、X 射线衍射仪(XRD)、透射电镜(TEM)及分光光度法进行了表征. 结果表明, 通过调制电沉积过程的脉冲参数, 能够实现质子交换膜燃料电池(PEMFC)电极Pt催化剂的直接电化学沉积, 能够调控电沉积Pt粒径, 并能有效地缓解电沉积过程中析氢对沉积金属催化剂铂的干扰, 所沉积的Pt 催化剂利用率较传统Nafion 粘接Pt/C催化电极要高. 脉冲导通时间ton 为300 μs、断通时间toff 为1200 μs, 脉冲峰值电流密度jp 为100 mA·cm-2 时, 电沉积120 s制得的电极的Pt 晶粒约5-8 nm, Pt 表面利用率为43.14%, 沉积Pt的电流效率为45%.

PEMFC Electrodes Platinized by Modulated Pulse Current Electrodeposition

Proton exchange membrane fuel cells (PEMFC) electrodes were platinized by a modulated pulse current electrodeposition. An uncatalyzed carbon electrode (UCE), on which a layer of Nafion-bonded carbon was dispersed in advance, was served as a substrate for electrodeposition. The platinized electrode by electrodeposition was assessed by cyclic voltammetry, X-ray diffraction, transmission electron microscopy. The preliminary results showed that the height and width of deposition pulse current were critical for the properties of Pt deposit. For instance, as the on-time and off-time were fixed at 300 μs and 1200 μs, respectively, and deposition time fixed at 120 s, the electrode prepared at a peak current density of 100 mA·cm-2 exhibited the best performance, and meanwhile the particle size of the Pt deposits was as small as 5-8 nm. The Pt utilization efficiency of such an electrode was as high as 43.14%. The current efficiency for Pt deposition, in this case, was about 45%.