Frenzel Ninett, Hartley Jennifer, Frisch Gero
Institut für Anorganische Chemie, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany.
Phys Chem Chem Phys. 2017 Nov 1;19(42):28841-28852. doi: 10.1039/c7cp05483a.
Ionic liquids and deep eutectic solvents have great potential in metallurgical applications as specialised solvents. In order to design ionometallurgical electrowinning and electrorefining processes, it is essential to characterise the electrochemical behaviour of metal complexes and compare potentials between relevant solvents. For such investigations, a universal reference redox couple would be desirable. In this study we investigate the speciation and electrochemical behaviour of ferrocenium/ferrocene and hexacyanoferrate(iii/ii) as possible reference couples for 15 different ionic media on platinum (Pt), glassy carbon (GC) and gold (Au) working electrodes. Amongst other parameters, formal electrode potentials, charge transfer coefficients, and rate constants were calculated. It was found that neither ferrocene nor hexacyanoferrate are universally suitable as redox standards in the liquids investigated. Nevertheless, hexacyanoferrate exhibits clear advantages in most of the strongly coordinating ionic liquids studied here.
离子液体和深共熔溶剂作为特殊溶剂在冶金应用中具有巨大潜力。为了设计离子冶金电解沉积和电解精炼工艺，表征金属配合物的电化学行为并比较相关溶剂之间的电位至关重要。对于此类研究，需要一个通用的参比氧化还原电对。在本研究中，我们研究了二茂铁鎓/二茂铁和铁氰酸盐（III/II）在铂（Pt）、玻碳（GC）和金（Au）工作电极上作为15种不同离子介质的可能参比电对的形态和电化学行为。除其他参数外，还计算了形式电极电位、电荷转移系数和速率常数。结果发现，在所研究的液体中，二茂铁和铁氰酸盐都不是普遍适合作氧化还原标准的。然而，铁氰酸盐在此处研究的大多数强配位离子液体中表现出明显优势。
