Texas Materials Institute & Department of Mechanical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
Langmuir. 2017 Jun 13;33(23):5652-5656. doi: 10.1021/acs.langmuir.7b00913. Epub 2017 May 31.
The induction time for the nucleation of hydrates can be significantly reduced by electronucleation, which consists of applying an electrical potential across the hydrate precursor solution. This study reveals that open-cell aluminum foam electrodes can reduce the electronucleation induction time by 150× when compared to nonfoam electrodes. Experiments with tetrahydrofuran hydrates show that aluminum foam electrodes trigger near-instantaneous nucleation (in only tens of seconds) at low voltages. Furthermore, this study suggests that two distinct interfacial mechanisms influence electronucleation, namely, electrolytic bubble generation and the formation of metal ion complex-based coordination compounds. These mechanisms (which depend on the electrode material and polarity) affect the induction time to vastly different extents. Coordination compound formation (verified via detection of metal ions in solution) exerts a much greater influence on electronucleation than the mechanistic effects associated with bubble generation. This work uncovers the benefits of using foams to promote electronucleation and shows that foams lead to more deterministic (as opposed to stochastic) nucleation when compared with nonfoam electrodes.
水合物成核的诱导时间可以通过电成核显著缩短，电成核包括在水合物前体溶液中施加电势。本研究表明，与非泡沫电极相比，开孔泡沫铝电极可以将电成核诱导时间缩短 150 倍。使用四氢呋喃水合物的实验表明，泡沫铝电极在低电压下引发近乎瞬时成核（仅需数十秒）。此外，本研究表明，两种不同的界面机制影响电成核，即电解气泡的生成和基于金属离子配合物的配位化合物的形成。这些机制（取决于电极材料和极性）在很大程度上影响诱导时间。配位化合物的形成（通过检测溶液中的金属离子来验证）对电成核的影响远大于与气泡生成相关的机械效应。这项工作揭示了使用泡沫来促进电成核的好处，并表明与非泡沫电极相比，泡沫会导致更确定的（而不是随机的）成核。
