Pollet Bruno G, Foroughi Faranak, Faid Alaa Y, Emberson David R, Islam Md H
Hydrogen Energy and Sonochemistry Research Group, Department of Energy and Process Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
Hydrogen Energy and Sonochemistry Research Group, Department of Energy and Process Engineering, Faculty of Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
Ultrason Sonochem. 2020 Dec;69:105238. doi: 10.1016/j.ultsonch.2020.105238. Epub 2020 Jun 26.
In this study, we investigated the effects of power ultrasound (26 kHz, up to ∼75 W/cm, up to 100% acoustic amplitude, ultrasonic horn) on the hydrogen evolution reaction (HER) on a platinum (Pt) polycrystalline disc electrode in 0.5 M HSO by cyclic and linear sweep voltammetry at 298 K. We also studied the formation of molecular hydrogen (H) bubbles on a Pt wire in the absence and presence of power ultrasound using ultra-fast camera imaging. It was found that ultrasound significantly increases currents towards the HER i.e. a ∼250% increase in current density was achieved at maximum ultrasonic power. The potential at a current density of -10 mA/cm under silent conditions was found to be -46 mV and decreased to -27 mV at 100% acoustic amplitude i.e. a ΔE shift of ∼+20 mV, indicating the influence of ultrasound on improving the HER activity. A nearly 100% increase in the exchange current density (j) and a 30% decrease in the Tafel slope (b) at maximum ultrasonic power, was observed in the low overpotential region, although in the high overpotential region, the Tafel slopes (b) were not significantly affected when compared to silent conditions. In our conditions, ultrasound did not greatly affect the "real" surface area (A) and roughness factor (R) i.e. the microscopic surface area available for electron transfer. Overall, it was found that ultrasound did not dramatically change the mechanism of HER but instead, increased currents at the Pt surface area through effective hydrogen bubble removal.
在本研究中，我们通过循环伏安法和线性扫描伏安法，在298K下研究了功率超声（26kHz，高达~75W/cm，高达100%声振幅，超声变幅杆）对0.5M硫酸中铂（Pt）多晶圆盘电极上析氢反应（HER）的影响。我们还使用超高速相机成像技术，研究了在有无功率超声的情况下，铂丝上分子氢（H）气泡的形成。结果发现，超声显著增加了HER的电流，即在最大超声功率下电流密度增加了约250%。发现在无超声条件下，电流密度为-10mA/cm²时的电位为-46mV，在100%声振幅下降至-27mV，即ΔE偏移约+20mV，表明超声对提高HER活性有影响。在低过电位区域，观察到最大超声功率下交换电流密度（j）增加了近100%，塔菲尔斜率（b）降低了30%，尽管在高过电位区域，与无超声条件相比，塔菲尔斜率（b）没有受到显著影响。在我们的条件下，超声对“真实”表面积（A）和粗糙度因子（R）即可用于电子转移的微观表面积影响不大。总体而言，发现超声并没有显著改变HER的机制，而是通过有效去除氢气泡增加了Pt表面积处的电流。
