Miniature H₂/O₂ fuel cells using TiO₂ nanotube substrates and sputtered Pt catalyst

Modified designs for a miniature H₂/air fuel cell are described using Pt sputtered on titanium oxide nanotube (Pt/TONT) as a catalyst at low mass loadings. Titanium microgrids or Ti evaporated onto a silicon substrate with holes at the center were used as substrates that were then anodized in fluoride-containing electrolytes to form the TONT arrays. Self-organized tubes grew as anodizing time increased, resulting in the highly enhanced surface area for electrochemical reactions. High cathodic current on cyclic voltammogram of Pt/TONT catalyst indicated high catalytic activity for the oxygen reduction reaction (ORR). The miniature fuel cells were successful, and showed high power densities up to 9.64 mW cm^-2 at potentials from 0.7 V to 0.2 V.