Pt/Nafion界面氧还原电极动力学

Electrode Kinetics of Oxygen Reduction at Pt/Nafion Interfaces

针对质子交换膜燃料电池所用的含有铂黑或碳载铂电催化剂的多孔气体扩散电极，采用循环伏安技术和塔菲尔曲线法，以氢、氧为反应气，对不同温度和压力下的Pt/Nafion界面的氧还原电极动力学进行了研究．解释了铂含量和浸入Nafion对电极动力学参数的影响．当电流密度小于1A／cm2时，与温度、氧压力和电极类型无关，塔菲尔斜率约为-60mA/dec.氧的反应级数为1级．在电极催化层内浸入Nafion只是增大了电化学活性表面积，对电极动力学参数无影响．

The electrode kinetics of oxygen reduction at the Pt/Nafion interface was investigated as function of temperature and pressure. The studies were conducted using porous gas diffusion electrodes, containing unsupported platinum (6mg/cm2) or carbon-supported platinum (0.8mg/cm2), in proton exchange membrane fuel cell, using H2 and O2 as reaCtants. The effects of platinum loading and of Nafion inpregnation on the electrode kinetic parameters were elucidated. When current densities lower than 1000mA/cm2, the Tafel slope was about -60mV per decade and was practically independent of temperature, O2 pressure and types of electrode. The effect of Nafion inpregnation was to increase the platinum utilization by increasing the three dimensional reaction zone.