Iodine adlayer mediated gold electrooxidation in bis(trifluoromethylsulfonyl)amide-based ionic liquids
Iodine adlayer mediated gold electrooxidation in bis(trifluoromethylsulfonyl)amide-based ionic liquids
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DOI：
10.1016/j.electacta.2021.137811
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发表时间：
2021-03
影响因子：
6.6
通讯作者：
H. Ueda;Koichi Nishimori;Tomohiro Hisatomi;Y. Shiraishi;Soichiro Yoshimoto
中科院分区：
文献类型：
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作者：
H. Ueda;Koichi Nishimori;Tomohiro Hisatomi;Y. Shiraishi;Soichiro Yoshimoto
湿法蚀刻金的传统络合配体是危险的，使其难以大规模应用。特别是，必须尽量减少这些材料造成的环境风险。为了解决这一问题，开发了一种以双（三氟甲基磺酰）酰胺（[Tf2N] -）为基的离子液体（ILs）电化学蚀刻金的方法。在这里，只需要一层常规络合配体，即金上的碘，就可以在正电极电位下实现金的连续溶解。此外，蚀刻行为涉及牺牲阳极电解（SAE）以生成金纳米颗粒（AuNPs）。研究发现，金的电化学氧化与卤化物离子的类型密切相关，碘修饰的金电极在[Tf2N] -基ILs中产生了较大的氧化峰。碘修饰金电极的伏安谱表明，电化学氧化过程中所消耗的电子电荷受IL阳离子和金的晶体取向的影响，分别随着铵<咪唑<吡啶和Au(111) < Au(100) < Au（110）而增加。在本研究评估的IL阴离子中，仅在基于[Tf2N]的IL中观察到碘修饰金电极的明显氧化峰，这表明[Tf2N]阴离子促进了金的络合并起到了配体的作用。此外，显微和光谱测量提供了电化学氧化后金溶解和金配合物形成的证据，随后产生aunp。研究结果揭示了[Tf2N]基il中碘催化金电化学氧化的机理。本文报道的金在IL中的电解为获得具有IL阴离子和aunp的新型金酸盐开辟了途径。
Conventional complexing ligands for the wet etching of gold are hazardous, making large-scale utilization problematic. In particular, the environmental risks caused by these materials must be minimized. To address this problem, an electrochemical etching method for gold using bis(trifluoromethylsulfonyl)amide ([Tf2N]–)-based ionic liquids (ILs) has been developed. Here, only one layer of conventional complexing ligand, that is, iodine on gold, is required to achieve the continuous dissolution of gold under a positive electrode potential. In addition, the etching behavior involves sacrificial anode electrolysis (SAE) to generate gold nanoparticles (AuNPs). It was found that the electrochemical oxidation of gold is strongly dependent upon the type of halide ion, and the iodine-modified gold electrode produced a large oxidation peak in [Tf2N]–-based ILs. The voltammetric profiles of iodine-modified gold electrodes reveal that the electronic charge consumed during the electrochemical oxidation is affected by the IL cation and the crystallographic orientation of gold, increasing as ammonium < imidazolium < pyrrolidinium and Au(111) < Au(100) < Au(110), respectively. Of the IL anions evaluated in this study, the apparent oxidation peak was only observed for iodine-modified gold electrode in [Tf2N]–-based ILs, suggesting that [Tf2N]–anions promote gold complexation and act as ligands. Further, microscopic and spectroscopic measurements provide evidence of gold dissolution after electrochemical oxidation and the formation of gold complexes, followed by the generation of AuNPs. The results reveal a mechanism for the iodine-catalyzed electrochemical oxidation of gold in [Tf2N]–-based ILs. The electrolysis of gold in the ILs reported here opens avenues for acquiring novel aurate salts with IL anions and AuNPs.