Preparation of an octahedral PtNi/CNT catalyst and its application in high durability PEMFC cathodes

Abstract

In order to promote the application of proton exchange membrane fuel cells (PEMFCs) in electric vehicles (EVs), it is important to improve the activity of cathode catalysts and the corrosion resistance of carbon supports under high potentials formed during transient vehicle operating conditions. An octahedral PtNi/CNT catalyst with a well-defined structure and enhanced oxygen reduction reaction (ORR) performance was prepared through a surfactant-assisted solvothermal method. Its mass activity and specific activity reach 5.5 and 8.5 times those of the commercial Pt/C catalyst, respectively, and its stability is also higher after durability testing. In addition, the membrane electrode assembly (MEA) fabricated using the octahedral PtNi/CNT catalyst in a cathode exhibits extremely outstanding durability under high potential, and the attenuations of its maximum power density and cell voltage at 600 mA cm-2 are only 4.8% and 3.6%, respectively, which are far below those of the control prepared with commercial Pt/C. These results demonstrate that carbon materials with a graphite structure exhibit actual application potential in the preparation of octahedral catalysts. These carbon-supported octahedral catalysts are expected to be applied in PEMFC cathodes after the materials and preparation process are further improved.