Abstract
Pt-supported on multi-walled carbon nanotubes (MWCNT) and N-modified MWCNT (N-MWCNT) catalysts are synthesized by pyrolysis from emeraldine solution and microemulsion. Their electrochemical properties and carbon corrosion resistance in a Proton Exchange Membrane Fuel Cell (PEMFC) are compared with a commercial Pt/Vulcan catalyst through I–V curves, cyclic voltammetry and CO stripping. The initial fuel cell performances of the Pt/(N-)MWCNT catalysts are superior to Pt/Vulcan. The corrosion of the catalysts is quantified by the continuous measure of the CO2 release by online-mass spectrometry during potentiodynamic cycling between 0.1 and 1.6 V at 80 °C. The results show that Pt/MWCNT (with the lowest double-layer capacity) is the most stable catalyst followed by Pt/N-MWCNT and Pt/Vulcan, initially losing carbon at a rate of 1.1, 3.4 and 4.7 μgC (mg Ctot)−1 cycle−1, respectively. After about 30% carbon loss (50–70 cycles) all catalysts corrode at an approximate rate of 5.5 μgC mg−1 cycle−1. At this stage, all show similar electrochemical surface area and double-layer capacity. However, the substantial diminution of the initially very thick and porous Pt/(N-)MWCNT catalyst layers after corrosion consequences in lower fuel cell performance compared to the structurally less affected Pt/Vulcan electrode. The results clearly reveal that CNT-based catalyst supports are more corrosion resistant compared to state-of-the-art Vulcan. Moreover, the performance of the corroded electrodes envisages the importance of electrode porosity.
Original language | English |
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Article number | 135384 |
Journal | Electrochimica Acta |
Volume | 332 |
DOIs | |
Publication status | Published - 1 Feb 2020 |
MoE publication type | A1 Journal article-refereed |
Funding
Dr. J. Solla-Gullon (Universidad de Alicante) is thanked for introducing the emulsion synthesis methods. PK gratefully acknowledges Jenny and Antti Wihuri Foundation for funding the research and postdoctoral visit at KTH Stockholm. Aalto University acknowledges the funding from DEMEC, SUPER and CloseLoop projects of Academy of Finland (n:o 13286266 , 13292554 , 13303452 ). The provision of facilities and technical support by Aalto University at OtaNano - Nanomicroscopy Center (Aalto-NMC) is also acknowledged. From the KTH’s side the governmental initiative “StandUp for Energy” is acknowledged as well as the Swedish Energy Agency FFI project 37806-3. Appendix A
Keywords
- Carbon corrosion
- Carbon nanotubes
- Mass spectrometry
- Oxygen reduction
- PEMFC