- The full article entitled “Confinement-driven hydrogen evolution reaction on gold surface” can be found at the Electrochimica Acta website at https://doi.org/10.1016/j.electacta.2025.146930
- Authors: Tzu-Hsuan Huang, Valentina Wieser, Dominik Dworschak, Hsiu-Wei Cheng*
Owing to growing concerns about global warming, the demand for clean and sustainable energy carriers, such as hydrogen, has become increasingly urgent. One way to produce hydrogen is through electrochemical water splitting. It should be noted that the reactivity of hydrogen production in this reaction is strongly influenced by the local environment at the electrode. Although current research focuses primarily on modifying electrode materials to enhance reactivity, the significance of confined geometries near the electrode remains unexplored. In this work, we utilized an Electrochemical Surface Force Apparatus (EC-SFA) to construct a precise confinement geometry between a gold and mica surface with nanometer precision. Our results show that this confined geometry significantly promotes HER reactivity, shifting the bubble evolution potential by approximately 200 mV towards more positive values compared to unconfined conditions. We further explored potential mechanisms underlying this phenomenon, including the overlapping of electric double layers (EDLs) between mica and gold surfaces, the nonuniform surface potential distribution under confinement, and changes in bubble kinetics. Our findings provide deeper insight into how confinement geometry near electrodes can be leveraged to improve catalytic performance, thus providing a novel strategy for optimizing water-splitting electrocatalysis.
