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Investigation of mixed-metal (oxy)fluorides as a new class of water oxidation electrocatalysts.
Chemical Science ( IF 7.6 ) Pub Date : 2019-09-10 , DOI: 10.1039/c9sc04027g
Kévin Lemoine 1 , Jérôme Lhoste 1 , Annie Hémon-Ribaud 1 , Nina Heidary 2 , Vincent Maisonneuve 1 , Amandine Guiet 1 , Nikolay Kornienko 2
Affiliation  

The development of electrocatalysts for the oxygen evolution reaction (OER) is one of the principal challenges in the area of renewable energy research. Within this context, mixed-metal oxides have recently emerged as the highest performing OER catalysts. Their structural and compositional modification to further boost their activity is crucial to the wide-spread use of electrolysis technologies. In this work, we investigated a series of mixed-metal F-containing materials as OER catalysts to probe possible benefits of the high electronegativity of fluoride ions. We found that crystalline hydrated fluorides, CoFe2F8(H2O)2 and NiFe2F8(H2O)2, and amorphous oxyfluorides, NiFe2F4.4O1.8 and CoFe2F6.6O0.7, feature excellent activity (overpotential for 10 mA cm-2 as low as 270 mV) and stability (extended performance for >250 hours with ∼40 mV activity loss) for the OER in alkaline electrolyte. Subsequent electroanalytical and spectroscopic characterization hinted that the electronic structure modulation conferred by the fluoride ions aided their reactivity. Finally, the best catalyst of the set, NiFe2F4.4O1.8, was applied as anode in an electrolyzer comprised solely of earth-abundant materials, which carried out overall water splitting at 1.65 V at 10 mA cm-2.

中文翻译:

混合金属(氧)氟化物作为新型水氧化电催化剂的研究。

用于氧气析出反应(OER)的电催化剂的开发是可再生能源研究领域的主要挑战之一。在这种情况下,混合金属氧化物最近已成为性能最高的OER催化剂。为了进一步提高其活性,对它们进行结构和成分修饰对于电解技术的广泛应用至关重要。在这项工作中,我们研究了一系列混合的含F的材料作为OER催化剂,以探究氟化物离子高电负性的可能益处。我们发现结晶水合氟化物CoFe2F8(H2O)2和NiFe2F8(H2O)2以及无定形氟氧化物NiFe2F4.4O1.8和CoFe2F6.6O0.7具有出色的活性(10 mA cm-2的超电势低至270 mV)和稳定性(扩展性能> 碱性电解液中的OER约250小时,活性损失约40 mV。随后的电分析和光谱表征表明,氟离子赋予的电子结构调节有助于它们的反应性。最后,将一组最好的催化剂NiFe2F4.4O1.8用作仅由富含稀土的材料构成的电解槽中的阳极,该电解槽在1.65 V的电压下于10 mA cm-2进行了总水分解。
更新日期:2019-10-17
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