Pt纳米粒子修饰的多孔硅电极的制备及其电催化性能

通过循环伏安法电沉积使直径约为7 nm的Pt纳米粒子均匀地分散于多孔硅表面, 拟用作微型质子交换膜燃料电池的催化电极. 与刷涂法相比较, 电沉积Pt纳米粒子的多孔硅电极(Pt/Si)呈现出高的Pt利用率和增强的电催化活性. 当Pt载量为0.38 mg•cm−2时, 其电化学活性比表面积高达148 cm2•mg−1, 是刷涂相近质量的纳米Pt/C催化剂的多孔硅电极Pt-C/Si的2倍多；该修饰电极对甲醇氧化也呈现了增强的催化性能和好的稳定性, 在0.5 V(vs SCE)极化1 h后电流密度为4.52 mA•cm−2, 而刷涂了相近Pt量的Pt-C/Si电极的电流密度只有0.36 mA•cm−2.

Preparation of Pt Nanoparticle Modified Porous Silicon Electrode and Its Electrocatalytic Performance

Porous silicon electrodes with electrodeposited Pt nanoparticles by cyclic voltammetry (Pt/Si) could be used as catalytic electrodes in micro proton exchange membrane fuel cells. As-deposited Pt nanoparticles with a mean diameter of ca 7 nm are highly dispersed on the surface of porous silicon. As compared to the electrode prepared by brushing nanosized Pt/C catalyst on the surface of porous silicon (Pt-C/Si), the Pt/Si modified electrodes exhibited high Pt utilization and enhanced catalytic performances for the hydrogen adsorption/desorption and for methanol oxidation. The maximum electrochemical specific area of ca 148 cm2•mg−1 was obtained with an electrodeposited Pt loading of ca 0.38 mg•cm−2, which is ca 2 times higher than that of the Pt-C/Si electrode with similar Pt loading of ca 0.40 mg•cm−2. Such a Pt/Si electrode showed an enhanced catalytic activity for methanol oxidation. After polarization at 0.5 V(vs SCE) for 1 h in 0.5 mol•L−1 CH3OH+0.5 mol•L−1 H2SO4, the obtained current density on this electrode was ca 4.52 mA•cm−2, which was much higher than the current density of 0.36 mA•cm−2 on Pt-C/Si electrode, again assessing high catalytic activity and good stability of electrodeposited Pt modified electrodes.