High specific surface area Ce0.8Zr0.2O2 promoted Pt/C electro-catalysts for hydrogen oxidation and CO oxidation reaction in PEMFCs

Preparation of a Graphitized-Carbon-Supported PtNi Octahedral Catalyst and Application in a Proton-Exchange Membrane Fuel Cell

In this work, PtNi/GC octahedral nanocrystal catalysts are prepared using graphitized carbon (GC) to solve the problems of cathode catalysts in catalytic performance and proton-exchange membrane fuel cell application. The as-prepared supported catalysts exhibit well-crystallized octahedral morphologies and graphite layer structures with high corrosion resistance. Their mass activities and specific activities are 5 and 7 times higher than those of the commercial Pt/C. The sample with the best performance shows the cell voltage at 1000 mA cm^-2 of 0.672 V and maximum power density of 817.6 mW cm^-2 in the single-cell test, which are increased by 23 mV and 13.2 mW cm^-2 compared to the control. Especially after a high potential test, the above two parameters of this sample are reduced by only 5.6 and 8.4%, which are significantly lower than the attenuation of the control fabricated using Vulcan XC-72 carbon black. The work reveals that the GC-supported PtNi octahedral catalysts can give better consideration to the improvement of electrochemical and single-cell performances.

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

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.

The as-prepared octahedral PtNi/CNT catalyst exhibits enhanced ORR performance and single cell durability under high potential.