Grant: Strategic Projects - Group

A fuel cell is an energy conversion device that cleanly and efficiently converts chemical energy (fuel + air) directly into electrical power. In the current era of ever depleting oil and natural gas reserves, concerns regarding greenhouse gas emissions and climate change, and increasing attention to air quality, fuel cells address these issues by offering very high efficiency of operation with less CO2 production, and no emission of pollutants such as particulates, NOx or SOx. Proton exchange membrane (PEM) fuel cells, developed in Canada by Ballard Power Systems, operate by passing pure hydrogen through a porous anode layer and air through a porous cathode. Both electrodes consist of a mixture of ion conducting polymer and small particles of carbon decorated with nanoparticles of platinum (Pt) catalyst. Oxygen reduction, forming water as the product at the cathode, is the rate (power) limiting process in PEM fuel cells. Our research is aimed at improving the cathode performance, specifically by developing new types of very high surface area carbon support materials (ordered mesoporous carbons, OMC) that allow far better dispersion of the Pt catalyst, thus effectively decreasing the amount of Pt needed to generate the same amount of electricity for a given amount of fuel. Containing pores of uniform size ranging from 5 to 50 nanometers in diameter, the OMCs developed in this work will allow Pt nanoparticles to be better distributed, stabilized and utilized, thus increasing the overall rate of oxygen reduction. To better control their interactions with Pt, polymer phase, oxygen and produced water, the surfaces and pores of the carbon will be chemically modified. These approaches will allow lower quantities of Pt to be used so that the cost of PEM fuel cells is lowered overall. Another problem in conventional PEM fuel cells is that the carbon powders are susceptible to oxidation under certain operating conditions, thus degrading the performance of the fuel cell over time. By modifying the crystalline nature and surface properties of the OMCs, we will increase the resistance of the carbon supports to this type of corrosion, thus increasing PEM fuel cell durability.