Catalytic materials for fuel cell electrodes and method for their production

摘要

Layered catalyst structures for fuel cells, particularly for a Proton Exchange Membrane Fuel Cell (PEMFC), are produced by a reactive spray deposition technology process. The catalyst layers so produced contain particles sized between 1 and 15 nm and clusters of such particles of a catalyst selected from the group consisting of platinum, platinum alloys with transition metals, mixtures thereof and non-noble metals. The catalyst layers without an electrically conducting supporting medium exhibit dendritic microstructure, providing high electrochemically active surface area and electron conductivity at ultra-low catalyst loading. The catalyst layers deposited on an electrically conducting medium, such as carbon, exhibit three-dimensional functional grading, which provides efficient utilization as a catalyst, high PEMFC performance at the low catalyst loading, and minimized limitations caused by reactant diffusion and activation. The catalytic layers may be produced by a single-run deposition method.

主权项

1. A catalyst layer structure for a fuel cell electrode, the structure comprising a catalyst layer comprising catalyst particles 1-15 nm in size, the layer having a catalyst loading not more than 0.1 mg/cm2 and rendering PEM fuel cell performance of at least 0.6 W/cm2, the catalyst layer further comprising a proton conducting ionomer, and the structure having a catalyst concentration gradient in at least the z direction, the concentration increasing towards the membrane/catalyst layer interface, the gradient being linear at rates of 50-300 mg/cm2-cmz-direction, and wherein the gradient rates could follow other rates of change selected from parabolic and logarithmic rates of change.