Abstract: 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.

Key words: Porous silicon, Pt nanoparticle, Cyclic voltammetry, Micro proton exchange membrane fuel cell