Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH₂PO₄

We demonstrate cathodes for solid acid fuel cells fabricated by vapor deposition of platinum from the metalorganic precursor Pt(acac) 2 on the solid acid CsH 2 PO 4 at 210 °C. A network of platinum nanoparticles with diameters of 2−4 nm serves as both the oxygen reduction catalyst and the electronic conductor in the electrode. Electrodes with a platinum content of 1.75 mg/cm 2 are more active for oxygen reduction than previously reported electrodes with a platinum content of 7.5 mg/cm 2 . Electrodes containing <1.75 mg/cm 2 of platinum show significantly reduced catalytic activity and increased ohmic resistance indicative of a highly discontinuous catalytic-electronic platinum network.