Nucleation behavior and kinetics of single hydrogen nanobubble in ionic liquid system

Abstract

Bubbles generated on the electrode surface have been considered one of important factors limiting the efficiency of hydrogen evolution reaction (HER). However, the bubble formation behaviors have not been clearly defined, especially nanobubbles in ionic liquid system. In this work, single H2 nanobubbles generation characters are well investigated using platinum nanoelectrodes in ionic liquid (IL) during HER. The crucial factors (i.e., critical condition, geometry, and nucleation rapid of the H2 nanobubbles) are quantitatively conducted from the voltammograms. The results reveal that the H2 nanobubbles have a small contact angle (from 152° to 160°) and large bubble height (0.5–1.1 nm), which are favorable for subsequent detachment from nanoelectrode surface. Moreover, higher nucleation energy (7.5–15.3 kT) indicates that IL can suppress bubble formation. This work has gained a fundamental insight into the dynamic formation behaviors of H2 nanobubble in IL, which can guide us to study H2 bubbles in the HER influenced by various factors.