"Direct Injection" Bubble Growth Mediated by Nano-Interfaced Electrodes for Efficient Chlorine Production.

The chlor-alkali industry, with the chlorine evolution reaction (CER) as its core anodic process, accounts for nearly 4% of global electricity consumption. The development of energy-efficient and stable CER system is therefore urgently needed. Nano-interfaced electrodes exhibit superior catalytic performance, yet their mechanism for energy saving and system stability remains incompletely understood. Here, we combine a high-speed camera and confocal laser scanning microscope Platform to visualize and digitalize the bubble evolution and the bubble-induced overpotential (ƞbub). We provide direct visual evidence that the bubble-induced concentration gradients and fluid flow field disturbances are key regulators of overpotential, and that the nano-interfaced electrode exhibits an ƞbub of only approximately 49% of that of the flat-interfaced electrode. Specifically, the nano interface not only generates a stronger interfacial electric field and enhanced bubble-induced interfacial turbulence-which promote the Cl- migration to the electrode surface-but also induces a "direct-injection" mode of bubble growth that mitigates the accumulation of reaction products near the electrode. Moreover, the Cl- enrichment capacity of the nano interface endows the near-interface solution with ionic buffering capability, effectively suppressing potential fluctuations. This work demonstrates that regulating bubble dynamics is key to constructing energy-saving and stable gas-evolving electrochemical systems.