Catalysis for Low Temperature Fuel Cells

Much of the performance still to be gained in proton exchange membrane fuel cells (PEMFCs) in use today is available from improvements to the cathode, traditionally made from unsupported or carbon-supported platinum. The search for improved cathode electrocatalysts has resulted in the development of platinum alloys which if tailored to the desired stack operating conditions can double the activity for oxygen reduction. Recently, advances have been made in cathode design which have raised performance levels in PEMFCs. The new electrocatalysts and cathode designs have increased electrical efficiency and power densities to the PEMFC stack, needed for commercial use. Improvements have also been achieved at the anode, by developments in platinum-ruthenium anodes for carbon monoxide and cell reversal tolerance. In this first paper, new cathode materials and designs are discussed; a second paper to be published in the April issue will look at anode advances.