Abstract
The anti-corrosion properties of the carbon substrates of cathode catalysts play a vital role in the commercialization of fuel cell vehicles. Our report reveals the enhanced durability of graphitized carbon black catalyst substrates in polymer electrolyte membrane fuel cells (PEMFCs), tested under simulated start-stop cycling and high potential holding conditions. Graphitized carbon treated at various temperatures is used as the support for Pt catalysts. The catalyst utilizing graphitized carbon treated at 1800 °C demonstrates superior antioxidation properties and the inhibition of Pt particle coarsening. The decay ratio of the potential at 1000 mA cm−2 has been reduced from 34.9% (commercial Pt/C) to 0.5% during high potential holding accelerated stress testing. Correspondingly, the growth of Pt particles is reduced from 0.95 nm (commercial Pt/C) to 0.08 nm; that is, the coalescence of Pt particles is effectively alleviated upon using graphitized carbon black.
Highlights
The Pt/ECG1800 catalyst with the carbon support with the most complete graphite lattice was more resistant to electrochemical corrosion than catalysts with a defective graphite lattice support (Pt/EC-G1600) or structurally disordered carbon supports (Pt/EC and Pt/C-JM) during both stress testing protocols
During RDE testing, the Pt/EC-G1800 catalyst displayed the lowest amount of electrochemically active surface area (ECSA) loss and the lowest attenuation rate, less than half of the decay rate of commercial Pt/C-JM (18.1% vs. 38.6%)
According to the results following start-stop and highpotential accelerated stress test (AST) protocols using single cells, the catalyst particles on the graphitized carbon supports underwent the smallest amounts of growth among all the samples
Summary
Polymer electrolyte membrane fuel cells (PEMFCs) are regarded as a promising, clean power source for automobiles due to their high efficiency, high output power density, low operation temperature, and near-zero emissions.[1,2,3,4,5] Recently, Pt and Ptbased ultrasmall particles supported on carbon matrices have shown state-of-the-art performance toward the oxygen reduction reaction (ORR).[6,7,8] durability is still one of the major obstacles preventing the commercialization of PEMFCs.[9,10,11,12] There are numerous studies on the degradation of cathode catalysts; in these, Pt particle dissolution and agglomeration, and carbon support corrosion are considered the main reasons for this degradation.[13,14,15,16,17] the stability and anticorrosion properties of carbon supports for cathode catalysts play a vital role in the commercialization of PEMFCs.For automobile applications, the local cathode potential can reach as high as 1.5 V during starting and stopping due to the H2/air frontier, which accelerates the oxidization of the carbon support and speeds up the degradation of the PEMFC.[18,19] When carbon oxidation occurs, oxygen-containing functional groups are generated on the surface of the carbon support, weakening the interactions between the platinum particles and the carbon support. The platinum particles will migrate and agglomerate, nally detaching from the carbon support.[20,21] The interfacial structure formed between the Pt nanoparticles and carbon support changes because of the functional groups generated on the carbon surface.[22,23] The electrons in Pt nanoparticles near
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