Effect of Ni–Ru/CF electrode fabrication and wettability modification on hydrogen evolution reaction and bubble evolution behavior during water electrolysis
Yao Yao, Xiajing Chen, Mengyun Shi, Yu Qiu, Dongling Wu, Hongjie Yan, Liu Liu
{"title":"Effect of Ni–Ru/CF electrode fabrication and wettability modification on hydrogen evolution reaction and bubble evolution behavior during water electrolysis","authors":"Yao Yao, Xiajing Chen, Mengyun Shi, Yu Qiu, Dongling Wu, Hongjie Yan, Liu Liu","doi":"10.1016/j.ijhydene.2025.151758","DOIUrl":null,"url":null,"abstract":"<div><div>Alkaline water electrolysis has attracted extensive attention, but its low energy conversion efficiency remains one of the key challenges hindering its industrialization. In this study, Ni–Ru/CF catalyst electrodes were fabricated via electrodeposition, with key parameters including <span><math><msup><mrow><mi>Ru</mi></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> concentration in the deposition solution, deposition potential, and deposition time systematically optimized. The surface wettability of the electrodes was regulated by polytetrafluoroethylene (PTFE) solution impregnation, and the correlation mechanism between bubble evolution behavior and hydrogen evolution reaction (HER) efficiency on electrodes with different wettabilities was analyzed by combining high-speed imaging technology. Results show that the Ni–Ru/CF electrode fabricated under optimized deposition conditions (<span><math><msup><mrow><mi>Ru</mi></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span> concentration of 0.02 M, deposition potential of <span><math><mrow><mo>−</mo><mn>1</mn><mo>.</mo><mn>0</mn></mrow></math></span> V, and deposition time of 180 s) exhibits excellent HER performance, which is an overpotential of <span><math><mrow><mo>−</mo><mn>39</mn><mo>.</mo><mn>75</mn></mrow></math></span> mV at a current density of <span><math><mrow><mo>−</mo><mn>10</mn><mspace></mspace><mtext>mA</mtext><mspace></mspace><msup><mrow><mtext>cm</mtext></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>, a Tafel slope of 44.16 mV/dec, an electrochemical active surface area (ECSA) of 790 <span><math><mrow><mtext>cm</mtext><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>cm</mtext></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>, and a charge transfer resistance (<span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>ct</mi></mrow></msub></math></span>) of 2.19 <span><math><mi>Ω</mi></math></span>. The hierarchical structure of nanoparticles and nanoflowers significantly enhances the exposure of active sites, providing structural support for efficient HER. PTFE modification reveals the key influence of wettability on bubble behavior. As the PTFE concentration increases (0-0.25 wt%), the electrode hydrophobicity is enhanced, and the PTFE film leads to a decrease in ECSA and an increase in overpotential. High-speed imaging results indicate that bubbles on hydrophilic electrodes (without PTFE modification) are prone to detachment, with all bubble diameters less than 0.29 mm at a current density of <span><math><mrow><mo>−</mo><mn>50</mn><mspace></mspace><mtext>mA</mtext><mspace></mspace><msup><mrow><mtext>cm</mtext></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>. In contrast, the bubble diameter on hydrophobic electrodes (treated with PTFE) increases significantly. For the 0.25 wt% PTFE-modified electrode, the maximum bubble diameter reaches 2.65 mm at a current density of <span><math><mrow><mo>−</mo><mn>450</mn><mspace></mspace><mtext>mA</mtext><mspace></mspace><msup><mrow><mtext>cm</mtext></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span>, and the adhesion of large bubbles causes a significant decline in HER performance. By analyzing the entire process of bubble growth and detachment, this study elucidates the relationship between bubble evolution behavior on the electrode surface and electrolytic potential variations. Under low current densities, the potential variation caused by bubble detachment is small, while under high current densities, the potential oscillation amplitude of hydrophobic electrodes can reach 33 mV, thereby revealing the mechanism of mass transfer resistance and dynamic changes in the reaction area induced by bubble retention.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"182 ","pages":"Article 151758"},"PeriodicalIF":8.3000,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Hydrogen Energy","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0360319925047615","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Alkaline water electrolysis has attracted extensive attention, but its low energy conversion efficiency remains one of the key challenges hindering its industrialization. In this study, Ni–Ru/CF catalyst electrodes were fabricated via electrodeposition, with key parameters including concentration in the deposition solution, deposition potential, and deposition time systematically optimized. The surface wettability of the electrodes was regulated by polytetrafluoroethylene (PTFE) solution impregnation, and the correlation mechanism between bubble evolution behavior and hydrogen evolution reaction (HER) efficiency on electrodes with different wettabilities was analyzed by combining high-speed imaging technology. Results show that the Ni–Ru/CF electrode fabricated under optimized deposition conditions ( concentration of 0.02 M, deposition potential of V, and deposition time of 180 s) exhibits excellent HER performance, which is an overpotential of mV at a current density of , a Tafel slope of 44.16 mV/dec, an electrochemical active surface area (ECSA) of 790 , and a charge transfer resistance () of 2.19 . The hierarchical structure of nanoparticles and nanoflowers significantly enhances the exposure of active sites, providing structural support for efficient HER. PTFE modification reveals the key influence of wettability on bubble behavior. As the PTFE concentration increases (0-0.25 wt%), the electrode hydrophobicity is enhanced, and the PTFE film leads to a decrease in ECSA and an increase in overpotential. High-speed imaging results indicate that bubbles on hydrophilic electrodes (without PTFE modification) are prone to detachment, with all bubble diameters less than 0.29 mm at a current density of . In contrast, the bubble diameter on hydrophobic electrodes (treated with PTFE) increases significantly. For the 0.25 wt% PTFE-modified electrode, the maximum bubble diameter reaches 2.65 mm at a current density of , and the adhesion of large bubbles causes a significant decline in HER performance. By analyzing the entire process of bubble growth and detachment, this study elucidates the relationship between bubble evolution behavior on the electrode surface and electrolytic potential variations. Under low current densities, the potential variation caused by bubble detachment is small, while under high current densities, the potential oscillation amplitude of hydrophobic electrodes can reach 33 mV, thereby revealing the mechanism of mass transfer resistance and dynamic changes in the reaction area induced by bubble retention.
期刊介绍:
The objective of the International Journal of Hydrogen Energy is to facilitate the exchange of new ideas, technological advancements, and research findings in the field of Hydrogen Energy among scientists and engineers worldwide. This journal showcases original research, both analytical and experimental, covering various aspects of Hydrogen Energy. These include production, storage, transmission, utilization, enabling technologies, environmental impact, economic considerations, and global perspectives on hydrogen and its carriers such as NH3, CH4, alcohols, etc.
The utilization aspect encompasses various methods such as thermochemical (combustion), photochemical, electrochemical (fuel cells), and nuclear conversion of hydrogen, hydrogen isotopes, and hydrogen carriers into thermal, mechanical, and electrical energies. The applications of these energies can be found in transportation (including aerospace), industrial, commercial, and residential sectors.