Hydrogen Bubble Formation at Hydrogen-Insertion Electrodes

Abstract

Here we report a fundamental study of the H 2 bubble formation mechanism on a model hydrogen-insertion material, Pd. We demonstrated that the current required for H 2 bubble formation at Pd electrodes was over 10 times higher than that at nonhydrogen-insertion metal electrodes (Au and Pt). Using a newly developed nanoelectrode platform, we measured the critical condition for H 2 bubble formation on different electrode materials. We discovered, for the first time, that the bubble formation on Pd required nearly the same supersaturation of dissolved H 2 on the electrode surface as Au and Pt. The suppressed bubble generation on Pd relative to Au and Pt is caused merely by the hydrogen insertion into bulk Pd rather than the different surface energies of electrode materials. Our study provides new insights into the nanoscale H 2 bubble generation mechanism on hydrogen-insertion materials.

Lowering Interfacial Dissolved Gas Concentration for Highly Efficient Hydrazine Oxidation at Platinum by Fluorosurfactant Modulation

“…To investigate the impact of modulated surface tension on the dissolved-gas concentration at HzOR interface, we fabricated Pt nanoelectrodes following a previously published method. [18][19][20] First, a Pt tip with a nanometer-sized sharp end was fabricated in CaCl 2 solution through applying a sinusoidal wave of 110 Hz frequency and 4.3 V amplitude. Figure S6 shows the representative scanning electron microscopy (SEM) images of a sharpened Pt tip.…”

Recent progress in gas nanobubble electrochemistry

“…多种电催化产气反应体系, 并观测到了单个O 2 [29,30] 、 N 2 [31] 、CO 2 [32] 和D 2 [33] . 尽管循环伏安法在单纳米气泡成核研究中可以给 出丰富的稳态传质和电极反应动力学信息 [36] , 但在时 German等人 [37,38] 设计了一种电流阶跃法, 得以在恒定 [39] ; (b) 对应于单个H 2 气泡电化学成核的循环伏安曲线; (c) 不同尺寸Pt纳米电极表面H 2 气泡电化学行为的循环伏安曲线 [28] ; (d) Pt纳米电极上不同气体(H 2 、O 2 、N 2 、CO 2 、D 2 )纳米 气泡电化学成核电流(i p nb )与电极半径(a)的依赖关系; (e) 不同金属(Pt, Au, Pd)纳米圆盘电极上H 2 纳米气泡成核电流与电极半径 的依赖关系 [35] ; (f) 恒流法测定单纳米气泡成核诱导时间 [37] ; (g) 不同恒电流下纳米气泡成核诱导时间与累积概率分布图; (h) 来自循环伏安曲线的气泡成核电流的分布函数及理论预期对比 [39] (网络版彩图) 对于半径介于10至100 nm的球形气泡, 其寿命时 间介于1至100 μs. 而许多实验观察到的界面纳米气泡 具有较长的生命周期 [13] .…”

“…(d) Dependence of the voltammetric peak current on the Pt nanodisk radii for different gas bubbles: H 2 , O 2 , N 2 , CO 2 and D 2 . (e) Dependence of the voltammetric peak current for H 2 bubble nucleation at different nanoelectrodes: Pt, Au and Pd[35]. (f) Study of a H 2 bubble nucleation using a current step[37].…”

Editors' Choice—Critical Review—Mathematical Formulations of Electrochemically Gas-Evolving Systems

“…Significant progress in modeling of electrochemically gas-evolving bubbles has been presented, however, in most of these studies the modeling is focused on one or two stages of the bubble life cycle such as bubble formation, 156 growth, 157 or on simulating two-phase flows. 108 However, full understanding of the nature of these bubble demands taking into account all the associated physics for the entire life cycle.…”