Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis

In electrochemical processes, gas bubbles on the electrode can cause an increase in both overpotential and ohmic voltage drop which leads to higher energy consumption. Applying power ultrasound during water electrolysis can help to reduce the overpotential, enhance mass transfer, and save energy. In...

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Autores principales:	Kyung Min Cho, P.R. Deshmukh, Weon Gyu Shin
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Sonoelectrochemistry Ultrasound Bubble resistance Hydrogen evolution reaction Bubble dynamics Alkaline water electrolysis Chemistry QD1-999 Acoustics. Sound QC221-246
Acceso en línea:	https://doaj.org/article/e4904d7a3dd54563aa3cfed08ad75656
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spelling	oai:doaj.org-article:e4904d7a3dd54563aa3cfed08ad756562021-12-02T04:59:45ZHydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis1350-417710.1016/j.ultsonch.2021.105796https://doaj.org/article/e4904d7a3dd54563aa3cfed08ad756562021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S1350417721003382https://doaj.org/toc/1350-4177In electrochemical processes, gas bubbles on the electrode can cause an increase in both overpotential and ohmic voltage drop which leads to higher energy consumption. Applying power ultrasound during water electrolysis can help to reduce the overpotential, enhance mass transfer, and save energy. In this study, we investigated the effect of ultrasound (20 kHz) on the hydrogen evolution reaction (HER) on a stainless steel plate with varying concentrations of NaOH solutions at 298 K, using linear sweep voltammetry (LSV). We especially focused on understanding the bubble behavior on the stainless steel plate during HER using high-speed imaging in ultrasonic field. When ultrasound was applied to solutions with NaOH concentrations of 0.1, 0.5, 1 M, the current density increased by about 9.0, 5.9, 2.8 %, respectively. As the ultrasound irradiation began, the bubbles tended to hover around on the electrode surface, coalescing with other bubbles, rather than rising. When the size of the coalesced bubbles became too large to stay on the surface of the electrode, they were expelled from the ultrasonic field. The repeated collapse and coalescence of these bubbles was observed while they were rising. The velocity increased about 2 times when ultrasound irradiation began, and increased by more than 6 times in the ultrasonic field. More nucleation of bubbles was observed on the electrode in the ultrasonic field. Using ultrasound reduced the critical diameter of bubbles which detached from the electrode, from 58.0 to 15.9 μm, and the residence time of the bubbles, from 533 to 118 ms. Further, when the ultrasound was applied, the mean diameter of bubbles decreased from 71.8 to 17 μm. Hence, bubble coverage on the electrode surface decreased from 8.3 to 1 % despite an increase in the total number of bubbles. As a result, ultrasound was found to be effective for hydrogen production during water electrolysis, increasing current by the faster removal of gas from the stainless steel plate.Kyung Min ChoP.R. DeshmukhWeon Gyu ShinElsevierarticleSonoelectrochemistryUltrasoundBubble resistanceHydrogen evolution reactionBubble dynamicsAlkaline water electrolysisChemistryQD1-999Acoustics. SoundQC221-246ENUltrasonics Sonochemistry, Vol 80, Iss , Pp 105796- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Sonoelectrochemistry Ultrasound Bubble resistance Hydrogen evolution reaction Bubble dynamics Alkaline water electrolysis Chemistry QD1-999 Acoustics. Sound QC221-246
spellingShingle	Sonoelectrochemistry Ultrasound Bubble resistance Hydrogen evolution reaction Bubble dynamics Alkaline water electrolysis Chemistry QD1-999 Acoustics. Sound QC221-246 Kyung Min Cho P.R. Deshmukh Weon Gyu Shin Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
description	In electrochemical processes, gas bubbles on the electrode can cause an increase in both overpotential and ohmic voltage drop which leads to higher energy consumption. Applying power ultrasound during water electrolysis can help to reduce the overpotential, enhance mass transfer, and save energy. In this study, we investigated the effect of ultrasound (20 kHz) on the hydrogen evolution reaction (HER) on a stainless steel plate with varying concentrations of NaOH solutions at 298 K, using linear sweep voltammetry (LSV). We especially focused on understanding the bubble behavior on the stainless steel plate during HER using high-speed imaging in ultrasonic field. When ultrasound was applied to solutions with NaOH concentrations of 0.1, 0.5, 1 M, the current density increased by about 9.0, 5.9, 2.8 %, respectively. As the ultrasound irradiation began, the bubbles tended to hover around on the electrode surface, coalescing with other bubbles, rather than rising. When the size of the coalesced bubbles became too large to stay on the surface of the electrode, they were expelled from the ultrasonic field. The repeated collapse and coalescence of these bubbles was observed while they were rising. The velocity increased about 2 times when ultrasound irradiation began, and increased by more than 6 times in the ultrasonic field. More nucleation of bubbles was observed on the electrode in the ultrasonic field. Using ultrasound reduced the critical diameter of bubbles which detached from the electrode, from 58.0 to 15.9 μm, and the residence time of the bubbles, from 533 to 118 ms. Further, when the ultrasound was applied, the mean diameter of bubbles decreased from 71.8 to 17 μm. Hence, bubble coverage on the electrode surface decreased from 8.3 to 1 % despite an increase in the total number of bubbles. As a result, ultrasound was found to be effective for hydrogen production during water electrolysis, increasing current by the faster removal of gas from the stainless steel plate.
format	article
author	Kyung Min Cho P.R. Deshmukh Weon Gyu Shin
author_facet	Kyung Min Cho P.R. Deshmukh Weon Gyu Shin
author_sort	Kyung Min Cho
title	Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
title_short	Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
title_full	Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
title_fullStr	Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
title_full_unstemmed	Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
title_sort	hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/e4904d7a3dd54563aa3cfed08ad75656
work_keys_str_mv	AT kyungmincho hydrodynamicbehaviorofbubblesatgasevolvingelectrodeinultrasonicfieldduringwaterelectrolysis AT prdeshmukh hydrodynamicbehaviorofbubblesatgasevolvingelectrodeinultrasonicfieldduringwaterelectrolysis AT weongyushin hydrodynamicbehaviorofbubblesatgasevolvingelectrodeinultrasonicfieldduringwaterelectrolysis
_version_	1718400923153203200

Hydrodynamic behavior of bubbles at gas-evolving electrode in ultrasonic field during water electrolysis

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