Hydrogen bubble evolution and gas transport mechanism on a microelectrode determined by cathodic potential and temperature

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(7)

Published: July 1, 2024

Enhancing the efficiency of hydrogen production by optimizing gas product transfer within water electrolysis systems is essential. Employing high-speed photography and electrochemical techniques, entire process single bubble evolution on a Pt microelectrode surface was measured. Results reveal notable reduction in both detachment radius growth time with decreasing absolute potential (from −7 to −3 V) increasing reaction temperature 30 °C 50 °C). Additionally, comprehensive model estimating coverage presented, incorporating current as key influencing factors. This enables an accurate evaluation mass coefficients during absence forced flow. Furthermore, findings dominance bubble-induced micro-convection primary mass-transfer mechanism for products at high densities [O (105–106 A/m2)]. The results also indicate that coefficient increases inertia-controlled stage bubbles decreases controlled chemical reactions.

Language: Английский

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In Situ Observation and Electrical Signal Analysis of Different Bubble Detachment Modes on Microelectrode Surface

Journal of The Electrochemical Society, Journal Year: 2024, Volume and Issue: 171(7), P. 076501 - 076501

Published: June 25, 2024

The deactivation of the reaction surface caused by bubble covering is an important factor that causes decrease in efficiency water electrolysis. By combining electrochemical workstation with a high-speed camera, evolutionary properties hydrogen and potential were obtained on horizontal microelectrode diameter 100 μ m. During electrolysis, individual bubbles evolved periodically electrode surface. Under influence adsorption, detachment independent current density, but increase frequency increases. With ethylene glycol (EG) concentration, increased. When concentration EG greater than 7.5 g l −1 , tension solution lower water, at which time mode changes. Separating resistance from total resistance, it was found additional rapidly became smaller as increased until reached . decreases first then increases when 3

Language: Английский

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Pulsed dynamic electrolysis enhanced PEMWE hydrogen production: Revealing the effects of pulsed electric fields on protons mass transport and hydrogen bubble escape

Journal of Energy Chemistry, Journal Year: 2024, Volume and Issue: 100, P. 201 - 214

Published: Aug. 26, 2024

Language: Английский

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Porous Substrate Optimization for Efficient Water Electrolysis: Uncovering Electrocatalysts, Electrolyte, and Bubble Dynamics Effects

ACS Sustainable Chemistry & Engineering, Journal Year: 2024, Volume and Issue: 12(44), P. 16308 - 16319

Published: Oct. 18, 2024

Water electrolysis is a promising technique for producing hydrogen, clean energy carrier essential achieving sustainable society. Reducing costs to meet the hydrogen demand anticipated through operations at high current density. However, excessive bubble formation during high-current deteriorates performance. Engineering substrates could help minimize additional overpotential while maintaining sufficient electrocatalyst amounts. In this study, we discuss optimizing porous maximize oxygen evolution reaction (OER) and overall single-cell performance, using Ni mesh model structure with or without NiFeOx catalyst decoration. The numerical simulation was conducted reveal contribution of an increase in electrode thickness, which augments quantities. calculation predicts that OER decreases stacking number electrodes. This estimation aligns experimental results when density 10 mA cmgeo–2. monotonic trend not observed 800 cmgeo–2, showing optimal thickness offers lowest potential. depends on electrocatalyst's identity; electrocatalysts lower Tafel slope (NiFeOx over Ni) require thinner electrodes maximum We optical characterizations track primary size. When comparing size aperture size, correlation between accumulation within stacked meshes thicker becomes evident. Our study underscores importance simultaneous development electrocatalysts, electrolytes, substrates.

Language: Английский

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Insights into Bubble Dynamics in Water Splitting

ACS Energy Letters, Journal Year: 2024, Volume and Issue: unknown, P. 212 - 237

Published: Dec. 17, 2024

Water splitting is crucial for green hydrogen production, yet gas bubble dynamics has been underexplored until recently. Bubbles reduce electrochemically active surface area, increase overpotentials, and cause optical losses in (photo)electrochemical systems. Recent advancements both theoretical understanding experimental techniques have led to a deeper appreciation of the role that plays improving water performance. The present review revisits fundamental principles nucleation, growth, detachment during electrochemical reactions, highlighting recent progress single dynamics. Here we explore models behavior, observations using advanced techniques, strategies control We also discuss management devices enhance H2 production efficiency stability by facilitating effective detachment. In concluding section, outline prospects further studies future research directions needed overcome current challenges. This underscores critical achieving high performance provides roadmap directions.

Language: Английский

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Manipulating Boiling Bubble Dynamics on Under‐Liquid Superaerophobic Silicon Surfaces for High‐Performance Phase‐Change Cooling

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 5, 2025

Abstract Enhancing critical heat flux (CHF) and transfer coefficient (HTC) by promoting the nucleation, growth, departure of boiling bubbles has drawn significant attention owing to its wide applications. However, in‐depth understanding comprehensive manipulation under‐liquid bubble dynamics from in situ microscale perspectives remain challenging. Herein, observations analyses microsized ultra‐low surface tension fluorinated liquids (FLs) are conducted on superaerophobic silicon surfaces with crisscross microchannels selective nanowires. It is revealed that deep yet short nanowires enable ultrafast liquid spreading (<549.6 ms) ultralow adhesion (≈1.1 µN), while an appropriate spacing (240–600 µm) between minimizes time (<20.6 due timely coalescence. By verifying above principles through collaborative enhancement CHF HTC, optimized structure (microchannel depth ≈52.9 µm, microchannel ≈362.9 nanowire length ≈0 nm) obtained further implemented onto exposed Si a commercial CPU chip. Cooled phase‐change FLs, average temperature maintains ≈64.9 °C even under extreme power loads (≈130 W), far below than those conventional air‐cooling water‐cooling operations.

Language: Английский

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Enhancing Hydrogen Evolution Reaction through Coalescence-Induced Bubble Departure on Patterned Gold–Silicon Microstrip Surfaces

ACS Applied Materials & Interfaces, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 17, 2025

Hydrogen bubble adhesion to the electrode presents a major obstacle for green hydrogen generation via evolution reaction (HER) as it would induce undesired overpotential and undermine efficiency by reducing area, increasing transport resistance, creating an ion concentration gradient. While electrodes with aerophobic/hydrophilic surfaces have been developed facilitate detachment, they primarily rely on micro- nanostructured catalyst enhance buoyance-induced departure. Here, we demonstrate that introducing nonreactive yet more hydrophilic can promote coalescence-induced departure, thereby significantly improving HER performance. Through systematic study using patterned gold–silicon microstrip (GSM) varied gold strip widths (50–1600 μm), found width results in smaller departure diameter increased frequencies, leading 400 mV reduction at mA/cm2 50 μm wide GSM surfaces. These demonstrated superior performance compared plain surface, even 50% area. The optimal performance, characterized lowest total overpotential, was achieved 200 strips, highlighting intricate interplay between improved dynamics reduced

Language: Английский

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Boosting Electrode Performance and Bubble Management via Direct Laser Interference Patterning

ACS Applied Materials & Interfaces, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 30, 2025

Laser-structuring techniques like Direct Laser Interference Patterning show great potential for optimizing electrodes water electrolysis. Therefore, a systematic experimental study is performed to analyze the influence of spatial period and aspect ratio between structure depth on electrode performance pure Ni electrodes. Using statistical design experiments approach, it found that distance laser-structures decisive processing parameter improvement performance. Thus, electrochemically active surface area could be increased by factor 12 compared nonstructured electrode. For oxygen evolution reaction, significantly lower onset overpotential (≈ −164 mV at 100 mA cm–2) found. This explained superhydrophilic structured bubble growth, which leads number nucleation sites and, simultaneously, larger detached bubbles. Combined with fully wetted surface, this results in reduced blocking thus, ohmic resistance.

Language: Английский

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How dual hydrogen bubble evolution inhibits electrolytic performance

Journal of Power Sources, Journal Year: 2025, Volume and Issue: 632, P. 236356 - 236356

Published: Jan. 31, 2025

Language: Английский

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Unveiling the Influence of Ion-Specific Interactions on the Electrochemical Wettability Alteration of Cu-CuOx Surfaces

Colloids and Surfaces A Physicochemical and Engineering Aspects, Journal Year: 2025, Volume and Issue: unknown, P. 136350 - 136350

Published: Feb. 1, 2025

Language: Английский

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