Unveiling the role of counter-anions in amorphous transition metal-based oxygen evolution electrocatalysts
At the initial stage of the oxygen evolution reaction (OER) most electrocatalysts undergo structural and chemical surface reconstruction. While this reconstruction strongly influences their performance, it is frequently overlooked. Herein, we analyze the role of the oxidized anions, which is particu...
| Autores: | , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:271372 |
| Acceso en línea: | https://ddd.uab.cat/record/271372 https://dx.doi.org/urn:doi:10.1016/j.apcatb.2022.121988 |
| Access Level: | acceso abierto |
| Palabra clave: | Amorphous oxide Anion adsorption Structural reconstruction Leaching Oxygen evolution reaction |
| Sumario: | At the initial stage of the oxygen evolution reaction (OER) most electrocatalysts undergo structural and chemical surface reconstruction. While this reconstruction strongly influences their performance, it is frequently overlooked. Herein, we analyze the role of the oxidized anions, which is particularly neglected in most previous works. We introduce a range of different anionic groups (Cl, CHCOO, NO , SO ) on the surface of an amorphous ZnCoNiO catalyst by a facile proton etching and ion exchange method from a ZIF-8 self-sacrificial template. The structural and chemical properties of the obtained set of materials are thoroughly analysed and correlated with their electrocatalytic performance to study the effect of surface anionic groups, phase transition, metal leaching and defect generation on OER activity. Exploiting the control possibilities provided by the synthesis method here described and employing the uncovered property-performance correlations, the electrocatalyst is optimized. As a result, we produce ZnCoNiO-SO catalysts with outstanding OER performances, including a low overpotential of 252 mV at 10 mA cm with a small Tafel slope of 41.6 mV dec. Furthermore, this catalyst exhibits remarkable stability with negligible overpotential variation for 100 h. The excellent catalytic properties are rationalized using density functional theory calculations, showing that the surface-adsorbed anions, particularly SO , can stabilize the OOH* intermediate, thus enhancing the OER activity. This work offers new insight into the roles of metal leaching and surface-adsorbed anions in the OER progress and facilitates the rational design of highly-efficient electrocatalysts for OER. |
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