(Digital Presentation) Synthesis of Proton Exchange Membrane Fuel Cell Catalyst and Optimization of Membrane Electrode Assembly Preparation Parameters
Authors: Allikmäe Anna-Mai , Telpt Robert , Nerut Jaak , Teppor Patrick , Valk Peeter , Koppel Miriam , Aruväli Jaan , Lust Enn 
Published: September 2023

Reducing platinum content in proton exchange membrane fuel cells (PEMFCs) is one of the most essential development directions to secure the economic viability of PEMFC. Efforts are being made to synthesise new, more active catalysts and to optimise PEMFC assembly parameters. (1–4)
The study aimed to synthesise 60 wt% Pt/C catalyst and optimise catalyst loading on the electrodes, gasket thickness and coating strategy.
The catalyst was synthesised by depositing Pt nanoparticles on carbon black (Ketjenblack EC-300J) using ethylene glycol as a reducing agent and solvent (5–7). The studied catalyst was characterised by thermogravimetric analysis, X-ray diffraction and N2 sorption analysis. The synthesized catalyst material contained approximately 60 wt% of Pt, and the average platinum crystallite size was under 3 nm. The catalyst had a micro-mesoporous structure with a specific surface area of 320 m2 g−1.
For electrochemical characterisation, the measurements were performed in H2/air PEMFC. Using an ultrasonic coating system, the catalyst was deposited on the Nafion membrane or gas diffusion layer. A suitable gasket thickness was found using electrochemical measurements. The catalyst loading was varied on the anode between 0.05 and 0.50 mg cm−2 and on the cathode between 0.40 and 1.00 mg cm−2, leaving the catalyst loading constant on the non-variable electrode. Electrodes thickness depended linearly on the catalyst loading. The results showed that electrochemically active surface area does not depend on catalyst loading. Varying catalyst loading on the anode did not show a decrease in electrochemical activity; thus, the anode catalyst loading could be reduced to 0.05 mg cm−2. However, the electrochemical activity decreased at low cathode catalyst loadings. It was found that the cathode catalyst loading can be reduced to 0.60 mg cm−2.
Under optimised conditions, the electrochemical activity of the investigated material was excellent. The PEMFC current density was 0.81 A cm−2 at 670 mV, the maximum achieved power density 0.80 W cm−2 and the electrochemically active surface area 56 mPt
2 gPt
−1.

Acknowledgements

This work was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011) and the Estonian Research Agency project (personal research support group grant project No. PRG676).

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