Preparing a catalyst layer in magnetic field to improve the performance of proton exchange membrane fuel cells

Electro catalyst Pt-Co/multi-walled C nano-tubes were synthesized by using the modified polyol method with glycol as reducer. The magnetic-field-assisted fabrication of membrane electrode assemblies (MEAs) for proton exchange membrane fuel cells (PEMFCs) was proposed, to orient catalyst layers and increase the efficiency of catalyst utilization. PEMFCs with the magnetic-field-treated MEA (M-MEA) exhibited significant performance improvement over common MEA (C-MEA) without magnetic-field treatment. Under the same operating conditions, the maximum power density of MEA increased from 149.6 to 223.8 mW cm(-2) when C-MEA was replaced by M-MEA. Scanning electron microscope images showed that catalysts exhibited a "cluster-like structure'' in M-MEA opposed to a chaotic arrangement in C-MEA. Electrochemical impedance spectroscopy measurements revealed that M-MEA reaction resistance was lower than that of C-MEA. Cyclic voltammetry data showed an increment of almost 29.6 % in electrochemical surface area as a result of the magnetic-field treatment.