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Accueil > Séminaires > Archive des séminaires d’Utinam > 2020

Bruno Georges Pollet

The Use of Sound for the Development of Water Electrolyser and Fuel Cell Electrocatalysts

Séminaire conjoint UTINAM-plateforme MIFHySTO

jeudi 13 février 2020, 14h-16h

amphithéatre du bâtiment transfert de l’ENSMM

Bruno Georges Pollet

Hydrogen Energy and Sonochemistry research group
Department of Energy and Process Engineering, Faculty of Engineering
Norwegian University of Science and Technology (NTNU), Trondheim, Norvège

Résumé :

This presentation highlights some of the research works undertaken over the years by the Pollet ́s groups in Birmingham, Cape Town and Trondheim in the application of power ultrasound for the fabrication of electrolyser and fuel cell catalysts, electrodes and hydrogen production. The publication of ‘The use of ultrasound for the fabrication of fuel cell materials’ in the International Journal of Hydrogen Energy in 2010 [1] triggered an international interest in the use of power ultrasound (20 kHz – 1 MHz), sonochemistry (the use of ultrasound in chemistry) and sonoelectrochemistry (the use of ultrasound in electrochemistry) [2] [3] [4] for the synthesis of energy materials and useful gases [5]. This is due to the fact that these techniques allow the generation of nano-energy materials of controlled sizes and shapes in a one-pot synthetic approach [6]. Furthermore, these methods do not require intensive labour as well as the use of large amounts of toxic and environmentally hazardous solvents that are often used in conventional chemical methods. In 2009, Zin, Pollet and Dabalà published the first paper in the literature highlighting the synthesis of platinum (Pt) nanoparticles from aqueous solutions using sonoelectrochemistry [7].
Recently, Karousos et al. [8] showed that Vulcan XC-72 carbon black (CB) substrate can be decorated with sonoelectrochemically produced Pt in a one-pot-one-step process by combining galvanostatic pulsed electrodeposition and power ultrasound (20 kHz). In other studies, Pt and IrO2 nanoparticles were synthesized sonoelectrochemically at room temperature in a three-electrode set up using a ultrasonicating working electrode or sonoelectrode generating very short applied current pulses (a few ms) triggered and followed immediately by short ultrasonic pulses (a few ms at 24kHz) [9], [10]. Later on, Pollet et al. [11], [12]] showed that power ultrasound can be used for the in-situ fabrication of PEMFC electrodes [11] and Gas Diffusion Electrodes (GDEs) [11]. The electrodeposition of Pt on Gas Diffusion Layer (GDL) surfaces in dilute chloroplatinic acid solutions was performed potentiodynamically in the absence and presence of ultrasound (20kHz) at various ultrasonic powers. It was found that Pt electrodeposition required a substantial overpotential to drive the formation of Pt nuclei on GDL surfaces ; however, under sonication, Pt electrodeposition became more facile due to lower concentration and nucleation overpotentials, and overall currents were significantly increased compared to silent conditions. It was also observed that the ECSA was improved for Pt/GDL electrodes prepared under sonication. In 2011, a research collaboration with SonoTek Corporation (USA) led to a novel ultrasonic-spray (US) method for preparing GDEs on various commercial woven and non-woven GDLs at several Pt loadings in the range of 0.40–0.05mg cm −2 [13]. It was found that the GDEs prepared by the US method exhibited better performances compared to those prepared commercially, especially at low Pt loadings.

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Version imprimable du résumé (PDF)
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Brève biographie de Bruno Georges Pollet