Metal-Foam-Based Ultrafast Electronucleation of Hydrates at Low Voltages

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.