Fluorination-enabled Reconstruction of NiFe Electrocatalysts for Efficient Water Oxidation.
basic_science · Level V
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- Record sourced from PubMed, PMID 33258608.
- Also identified by DOI 10.1021/acs.nanolett.0c03950.
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Abstract
Developing low-cost and efficient electrocatalysts to accelerate oxygen evolution reaction (OER) kinetics is vital for water and carbon-dioxide electrolyzers. The fastest-known water oxidation catalyst, Ni(Fe)O<sub><i>x</i></sub>H<sub><i>y</i></sub>, usually produced through an electrochemical reconstruction of precatalysts under alkaline condition, has received substantial attention. However, the reconstruction in the reported catalysts usually leads to a limited active layer and poorly controlled Fe-activated sites. Here, we demonstrate a new electrochemistry-driven F-enabled surface-reconstruction strategy for converting the ultrathin NiFeO<sub><i>x</i></sub>F<sub><i>y</i></sub> nanosheets into an Fe-enriched Ni(Fe)O<sub><i>x</i></sub>H<sub><i>y</i></sub> phase. The activated electrocatalyst shows a low OER overpotential of 218 ± 5 mV at 10 mA cm<sup>-2</sup> and a low Tafel slope of 31 ± 4 mV dec<sup>-1</sup>, which is among the best for NiFe-based OER electrocatalysts. Such superior performance is caused by the effective formation of the Fe-enriched Ni(Fe)O<sub><i>x</i></sub>H<sub><i>y</i></sub> active-phase that is identified by <i>operando</i> Raman spectroscopy and the substantially improved surface wettability and gas-bubble-releasing behavior.