초록 ▼

A gas diffusion electrode for a proton exchange membrane fuel cell is prepared by electrodeposition of a catalytic metal in nanocrystalline form on a substrate by contacting an electrically conductive substrate and a counterelectrode with a plating bath containing ions of a metal to be deposited on

A gas diffusion electrode for a proton exchange membrane fuel cell is prepared by electrodeposition of a catalytic metal in nanocrystalline form on a substrate by contacting an electrically conductive substrate and a counterelectrode with a plating bath containing ions of a metal to be deposited on the substrate and passing a pulsed electric current between the substrate and counterelectrode having pulses that are cathodic with respect to the substrate and have a short on-time and/or a short duty cycle with a frequency from about 10 hertz to about 5000 hertz. In a preferred embodiment the electric current is a modulated reversing electric current having pulses that are cathodic with respect to the substrate and pulses that are anodic with respect to the substrate, the cathodic pulses having a short on-time and/or short duty cycle, the charge transfer ratio of the cathodic pulses to the anodic pulses being greater than one, and the frequency of the pulses ranging from about 10 hertz to about 5 kilohertz.

대표청구항 ▼

[ We claim:] [47.] A gas diffusion electrode for a proton exchange membrane fuel cell comprisinga gas-permeable electrically conductive backing layer;a catalyst layer supported on said backing layer, said catalyst layer having a thickness in a range of from about 0.1 micrometer to about 15 micromete

[ We claim:] [47.] A gas diffusion electrode for a proton exchange membrane fuel cell comprisinga gas-permeable electrically conductive backing layer;a catalyst layer supported on said backing layer, said catalyst layer having a thickness in a range of from about 0.1 micrometer to about 15 micrometers and comprisinga particulate, electrically conductive catalyst support dispersed in a proton exchange resin and in electrical contact with said backing layer, anda catalytic metal in finely divided form in electrical contact with said particulate catalyst support, said catalytic metal being present in the form of fine particles having diameter of from about 3.0 nanometers to about 8.0 nanometers and the loading of said catalyst being from about 0.1 mg/cm.sup.2 to about 1.0 mg/cm.sup.2.