2016

One of the most important challenges in decarbonizing the industry and creating sustainable mobility is the mass production of green H2. As long as electricity is renewable and electrolyzer technology satisfies OPEX and CAPEX performance, water electrolysis is the preferred technology in this situation
Proton Exchange Membrane Water Electrolysis (PEMWE) is one of the most promising technologies among various water electrolysis processes because it can (i) operate at close to room temperature (<100°C), (ii) at high current densities (>1 A/cm2), and (iii) produce extremely pure H2. Additionally, it can be connected to variable renewable energy sources. However, PEM water electrolysis has certain drawbacks, especially because it is expensive and requires platinum group metal (PGM) electrocatalysts [1,2,3]. Our strategy relies on implementing non-PGM electrocatalysts. Among them, we work on nanostructuration of electrodes further combined with either a little quantity of metal nanoparticles (Pt, Pd…) or cost-effective precious metal-free catalytic complexes based on Mo-S clusters (chalco-metal complexes or oxothiometallates) or Metal Organic Framework (MOF) in order to enhance their electrocatalytic turnover [4,5]. These electrocatalysts are either adsorbed or grafted to the nanostructured electrode using different techniques such as drop-casting, deep-coating, electrografting or spray-coating. Their morphology, chemical composition and crystal structure are characterized by electron microscopies, X-ray diffraction and X-ray photoelectron spectroscopy. Several reactions of great societal interest such as water splitting are considered and their electrocatalytic performances systematically evaluated for their implementation in the so-called Proton Exchange Membrane (PEM) technology. Moreover, the correlation between topography and electrochemical response at the electrocatalytic active sites scale is evaluated by AFM-SECM (Figure 1) [6]. This powerful technique allowed to determine the topological orientation effect of the catalysts on their electrochemical performance towards the hydrogen evolution reaction. Once the best material has been identified and optimized, it is prepared as a Membrane Electrode Assembly (MEA) and implemented in larger scale PEM electrolysis cells (5 to 250 cm2).

[1] A. C. Bhosale, P. C. Ghosh, L. Assaud, Renewable and Sustainable Energy Reviews 2020, 133, 110286
[2] I. Saad, S.-I. El Dek, M.-F. Eissa, L. Assaud, M. R. Abukhadra, W. Al Zoubi, J.-H. Kang, R. M. Amin, Inorganic Chemistry Communications 2024, 165, 112474
[3] M. Chatenet et al, Chem. Soc. Rev. 2022, 51, 4583
[4] J. Al Cheikh, A. Villagra, A. Ranjbari, A. Pradon, M. Antuch, D. Dragoe, P. Millet, L. Assaud, Appl. Cat. B : Environ. 2019, 250, 292-300
[5] S.-M. You, W.-M.-A. El Rouby, L. Assaud, R.-A. Doong, P. Millet, Hydrogen 2021, 2, 58-75
[6] A. Polyakov, S. Albacha, W. El Rouby, B. Munkhbat, L. Assaud, P. Millet, B. Wickman, T. Shegai, Materials Today Nano 2024, 25, 100467