High performance hydrogen fuel cells with ultralow Pt loading carbon nanotube thin film catalysts

Fuel cell membrane electrode assemblies with Pt loading of 0.2 ing pt/cm(2) at the anode and ultralow Pt loadings of 6 mu g pt/cm(2) and 12 mu g pt/cm(2) at the cathode have been fabricated using thin films of multiwalled carbon nanotube supported Pt catalysts (Pt/MWNTs) at the cathode. The Pt/MWNTs have a Pt weight loading of 26.8 wt % and a uniform and small Pt particle size of 2.1 nm. The MWNTs used are 360 mu m long. This thin film cathode catalyst layer with a loading of 6 mu g Pt/cm(2) is about 1.3 mu m thick, contains no ionomer, and exhibits surprisingly high performance in a hydrogen proton exchange membrane fuel cell. The peak power density for a membrane electrode assembly with a cathode loading of 12 mu g pt/cm(2) when tested at 70 degrees C with hydrogen and oxygen is 613 mW/cm(2). A mass activity (ampere per milligram of Pt) based on the cathode Pt loading greater than 250 A/mg Pt is achieved with 6 mu g Pt/cm(2), and this is among the highest reported to date.