Controlled preparation of porous silicon as diffusion layer for miniature fuel cell

Porous silicon (PS) due to its porous structure and large surface-to-volume ratio is prospective to substitute the traditional diffusion layer materials such as carbon paper or car- bon cloth in miniaturized fuel cell based on MEMS technology.On singal-crystalline silicon n＜100＞(0.04-0.15Ω.cm) PS film was prepared.In order to make the preparation controllable, the effects of various experimental conditions including HF concentration,current density and anodization duration on porosity,pore depth and anodization rate were systematically examined. The C-V curves of PS film with 40% porosity,500-700nm aperture and 60μm depth in 0.5mol/L H_2SO_4 solution indicate that PS electrode surfaces exhibit comparable catalytic activity with that of carbon paper.Therefore,the PS film shows potential application value inμPEMFCs.