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Blomme R, Ramesh R, Henderick L, Minjauw M, Vereecken P, Adriaens M, Detavernier C, Dendooven J. Atomic layer deposition for tuning the surface chemical composition of nickel iron phosphates for oxygen evolution reaction in alkaline electrolyzers. NANOTECHNOLOGY 2024; 35:235401. [PMID: 38417172 DOI: 10.1088/1361-6528/ad2e48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/28/2024] [Indexed: 03/01/2024]
Abstract
Transition metal phosphates are promising catalysts for the oxygen evolution reaction (OER) in alkaline medium. Herein, Fe-doped Ni phosphates are deposited using plasma-enhanced atomic layer deposition (PE-ALD) at 300 °C. A sequence offFe phosphate PE-ALD cycles andnNi phosphate PE-ALD cycles is repeatedxtimes. The Fe to Ni ratio can be controlled by the cycle ratio (f/n), while the film thickness can be controlled by the number of cycles (xtimes (n+f)). 30 nm films with an Fe/Ni ratio of ∼10% and ∼37%, respectively, are evaluated in 1.0 M KOH solution. Remarkably, a significant difference in OER activity is found when the order of the Ni and Fe phosphate PE-ALD cycles in the deposition sequence is reversed. A 20%-45% larger current density is obtained for catalysts grown with an Fe phosphate PE-ALD cycle at the end compared to the Ni phosphate-terminated flavour. We attribute this to a higher concentration of Fe centers on the surface, as a consequence of the specific PE-ALD approach. Secondly, increasing the thickness of the catalyst films up to 160 nm results in an increase of the OER current density and active surface area, suggesting that the as-deposited smooth and continuous films are converted into electrolyte-permeable structures during catalyst activation and operation. This work demonstrates the ability of PE-ALD to control both the surface and bulk composition of thin film electrocatalysts, offering valuable opportunities to understand their impact on performance.
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Affiliation(s)
- Ruben Blomme
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
| | - Rahul Ramesh
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
| | - Lowie Henderick
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
| | - Matthias Minjauw
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
| | - Philippe Vereecken
- IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
- KU Leuven, Department of Microbial and Micromolecular Systems (M2S), cMACS, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- Energyville, Thor Park 8320, B-3600 Genk, Belgium
| | - Mieke Adriaens
- Ghent University, Department of Chemistry, Faculty of Sciences, B-9000 Ghent, Belgium
| | - Christophe Detavernier
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
| | - Jolien Dendooven
- Ghent University, Department of Solid State Sciences, Conformal Coating of Nanostructures (CoCooN), Krijgslaan 281 S1, B-9000 Ghent, Belgium
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