Bubble Escape Research Articles

Biomass-Derived-Carbon-Supported Spinel Cobalt Molybdate as High-Efficiency Electrocatalyst for Oxygen Evolution Reaction.

Ananas comosus leaves were converted to a porous graphitized carbon (GPLC) material via a high-temperature pyrolysis method by employing iron salt as a catalyst. A cobalt molybdate (CoMoO4)-and-GPLC composite (CoMoO4/GPLC) was then prepared by engineering CoMoO4 nanorods in situ, grown on GPLC. N2 adsorption-desorption isothermal curves and a pore size distribution curve verify that the proposed composite possesses a porous structure and a large specific surface area, which are favorable for charge and reactant transport and the rapid escape of O2 bubbles. Consequently, the as-synthesized CoMoO4/GPLC shows low overpotentials of 289 mV and 399 mV to afford the current densities of 10 mA cm-2 and 100 mA cm-2 towards the oxygen evolution reaction (OER), which is superior to many CoMoO4-based catalysts in previous studies. In addition, the decrease in current density is particularly small, with a reduction rate of 3.2% after a continuous OER procedure for 30 h, indicating its good stability. The excellent performance of the CoMoO4/GPLC composite proves that the GPLC carrier can obviously impel the catalytic activity of CoMoO4 by improving electrical conductivity, enhancing mass transport and exposing more active sites of the composite. This work provides an effective strategy for the efficient conversion of waste ananas comosus leaves to a biomass-derived-carbon-supported Co-Mo-based OER electrocatalyst with good performance, which may represent a potential approach to the development of new catalysts for OER, as well as the treatment of waste biomass.

Record-high heat transfer performance of spray cooling on 3D-printed hierarchical micro/nano-structured surface

Managing high-flux waste heat with controllable device working temperature is becoming challenging and critical for the artificial intelligence, communications, electric vehicles, defense and aerospace sectors. Spray cooling, which combines forced convection with phase-change latent heat of working fluids, is promising for high flux heat dissipation. Most of the previous studies on spray cooling enhancement adopted high spray flow rates to strengthen forced convection for high critical heat flux (CHF), leading to a low heat transfer coefficient (HTC). Micro/nanostructured surfaces can enhance boiling, but bubbles inside the structures tend to form a vapor blanket, which can deteriorate heat transfer. This work demonstrates simultaneous enhancement of CHF and HTC in spray cooling by improving both evaporation and liquid film boiling on three-dimensional (3D) ordered hierarchical micro/nano-structured surface. The hierarchical micro/nanostructured surface is designed to coordinate the transport of spray droplets, capillary liquid films, and boiling bubbles to enhance spray cooling performance. Boiling inversion where superheat decreases with increasing heat flux is observed, leading to an ultra-high HTC due to the simultaneous promotion of bubble nucleation and evaporation. Unprecedented CHF is obtained by overcoming the liquid-vapor counterflow, i.e., synergistically facilitating bubble escape and liquid permeation. A record-breaking heat transfer performance of spray cooling is achieved with a maximum heat flux of 1273 W/cm2 and an HTC of 443.7 kW/(m2 K) over a 1 cm2 heating area.

Numerical investigation on the influence of porous media structural parameters on pool boiling heat transfer performance

This work investigates pool boiling heat transfer (BHT) and bubble dynamics from a porous medium. The influence of the porous media structural parameters, such as porosity, pore density, porous medium height, thermal conductivity, and wettability, are mainly investigated. The findings indicate that the presence of porous media can increase the critical heat flux (CHF) by an average of 3.75 times and the BHT coefficient by an average of 3.84 times when porosity varies between 57.5% and 98.0% as compared to the plain surface. It is also found that both the CHF and BHT coefficient increase as the porosity decreases if porosity ε≥71.4%. However, they drop with the porosity decreases if porosity ε≤71.4%. On the other hand, the number of nucleation sites, heat transfer area, and bubble escape resistance increase as pore density increases. In addition, increasing the porous media height may enhance BHT performance, but too high a porous media increases the bubble escape resistance and restricts the separation of bubbles. Moreover, the CHF value and the maximum BHT coefficient increase with the thermal conductivity of porous media linearly. Finally, the stronger the wettability, the faster the bubble detachment, and the stronger the BHT performance.

Accelerating gas escape efficiency by parallel alignment of nanosheets arrays for high-current oxygen evolution and urea oxidation

Electrocatalysts play a crucial role in energy production and chemical oxidation. Nonetheless, the efficacy of catalysts in expediting reactions is notably affected by the escape of bubbles and the re-exposure of active sites, particularly under high-current-density conditions. Herein, parallel-aligned Ni(OH)2 nanosheets array is anchored on nickel foam as substrate to verify mass transfer enhancement theory. Compare with disordered and interconnected nanosheets structures, parallel alignment of nanosheets array with superior mass transfer capability, larger exposed surface area, and spatial confinement effects is demonstrated to boost effective removal of in situ generated gas bubbles. Moreover, carbon coating layer with high electrical conductivity and nickel-iron-based composite with high activity is simultaneously anchored on parallel-aligned nanosheets surface (C@FeNi/NF-P). As illustration of application viability, C@FeNi/NF-P exhibits overpotential of 317 mV and potential of 1.45 V at 500 mA cm−2, respectively, for oxygen evolution (OER) and urea oxidation (UOR) with good stability. Moreover, the mass transfer enhancement effect of parallel aligned structure for the high active electrodes is also discussed. This work provides new insight for physical structural modulation of active materials to strengthen electrocatalytic activity with high mass-transfer efficiency, further ensuring high-efficient and stable water splitting and urea oxidation.

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

The transition of hydrogen sourcing from carbon-intensive to water-based methodologies is underway, with renewable energy-powered proton exchange membrane water electrolysis (PEMWE) emerging as the preeminent pathway for hydrogen production. Despite remarkable advancements in this field, confronting the sluggish electrochemical kinetics and inherent high-energy consumption arising from deteriorated mass transport within PEMWE systems remains a formidable obstacle. This impediment stems primarily from the hindered protons mass transfer and the untimely hydrogen bubbles detachment. To address these challenges, we harness the inherent variability of electrical energy and introduce an innovative pulsed dynamic water electrolysis system. Compared to constant voltage electrolysis (hydrogen production rate: 51.6 mL h−1, energy consumption: 5.37 kWh Nm−3 H2), this strategy (hydrogen production rate: 66 mL h−1, energy consumption: 3.83 kWh Nm−3 H2) increases the hydrogen production rate by approximately 27% and reduces the energy consumption by about 28%. Furthermore, we demonstrate the practicality of this system by integrating it with an off-grid photovoltaic (PV) system designed for outdoor operation, successfully driving a hydrogen production current of up to 500 mA under an average voltage of approximately 2 V. The combined results of in-situ characterization and finite element analysis reveal the performance enhancement mechanism: pulsed dynamic electrolysis (PDE) dramatically accelerates the enrichment of protons at the electrode/solution interface and facilitates the release of bubbles on the electrode surface. As such, PDE-enhanced PEMWE represents a synergistic advancement, concurrently enhancing both the hydrogen generation reaction and associated transport processes. This promising technology not only redefines the landscape of electrolysis-based hydrogen production but also holds immense potential for broadening its application across a diverse spectrum of electrocatalytic endeavors.

Porosity suppression mechanism analysis in narrow-gap oscillating laser-MIG hybrid welding of aluminum alloys based on keyhole stability and molten pool flow behavior

In this study, the keyhole dynamic behavior and molten pool flow were investigated to elucidate the effects of oscillating laser on porosity in narrow-gap oscillating laser-MIG hybrid welding of aluminum alloys. A weld with a porosity of 0.08% was produced at the laser oscillating frequency of 600 Hz and diameter of 1 mm, while 2.27% without oscillating laser. Compared to non-oscillating laser, keyhole opening size increased by about 2.3 times and keyhole depth fluctuation was suppressed. The forces acted on the interface between keyhole wall and molten pool became more balanced. The increased vapor recoil pressure overcame the combined closure effect of gravity and molten pool pressure. While applying oscillating laser, the vortex in molten pool was eliminated and the liquid metal flow was more stable. The combined impact force caused by droplets transfer and liquid metal convection due to constraining effect of narrow gap was buffered, which had less effect on molten pool and keyhole stability. The liquid metal tended to flow from the molten pool inside to surface, which favored the escape of bubbles from the molten pool.

Bubble desorption enhanced superareophilic cooperative electrode for hydrogen evolution reaction

The efficiency of the hydrogen evolution reaction (HER) is significantly influenced by the accumulation of the H2 bubbles at the electrode reaction interface. Superhydrophobic/underwater superaerophilic materials can expedite bubble desorption on board. Therefore, in this study, a superaerophilic titanium felt (SALTF) is fabricated and positioned opposite to the working electrode (Pt). The cooperative electrode is referred to as the Pt//SALTF electrode. With adjustable distance between the flat Pt and the SALTF, bubble transfer from the flat Pt to the SALTF can be observed between them. Due to the enhanced bubble escape process, the overpotential for the Pt//SALTF cooperative electrode is reduced by 20 mV at −10 mA cm−2 and reduced by 92 mV at −100 mA cm−2 compared to that of the flat Pt electrode. At an overpotential of −500 mV, the current density for the flat Pt electrode is −146 mA cm−2, which increases to −209 mA cm−2 after assembling the Pt//SALTF. This mode of assembly greatly enhances HER performance through mass transfer enhancement.

Numerical evaluation of interwire angle influence on molten pool fluid dynamics and weld defects in tandem NG-GMAW of 5083 aluminum alloy

The impact of interwire angle on the fluid dynamics and weld defects in tandem NG-GMAW of 5083 AlMg alloy was investigated through experimental and simulation methods. The rotating coordinate system was employed to model the inclined arc and arc interaction, while a pulsed Gaussian distribution arc model was adopted to consider factors such as arc heat, arc pressure and drag force. Experimental results demonstrate that different interwire angles lead to different weld formation and varying levels of porosity and pore distribution. A sound weld bead with no formation defect and low porosity was achieved when the interwire angle was set at 10°. Simulation results illustrate the relationship between weld formation, bubble escape and molten pool fluid dynamics under diverse interwire angles. As the interwire angle increases, the weld surface becomes concave. At the interwire angle of 0°, the weld bead surface appears leveled and porosity tends to occur near the sidewalls due to roundabout flows in that region. At an interwire angle of 14°, roundabout flows converge at the central longitudinal section, resulting in significant porosity in this area. However, when the interwire angle is set at 10°, backward flows driven by two arcs suppresses roundabout flow throughout the entire molten pool, leading to a lower percentage of porosity area.

Study on the effects of alloying elements on porosity in Al-Mg-Sc-Zr alloy fabricated by wire arc directed energy deposition

Wire arc directed energy deposition (WA-DED) technology has broad application prospects in man-ufacturing large-size and complex metal components due to its low production costs and high depos-ition efficiency. However, pores are still challenging in WA-DED-processed aluminum (Al) alloys. Although many works have been discussed in this field, the relevant studies about the effect of alloying elements on porosity are fewer. In this work, Al alloy wires with 0.36Sc and 0.11Zr (LAEW, wt%) and 0.72Sc and 0.23Zr (HAEW) were selected to fabricate single-pass multi-layer compone-nts with different welding speeds, and the pores were analyzed by X-ray computed tomography (XCT) technology. As the content of Sc and Zr elements increased, the density of Al-Mg-Sc-Zr components significantly decreased. The highest porosity, number density, and the largest average diameter of pores in components with HAEW were about 7.37 %, 6.04 × 102 /mm3, and 46.77 ± 29.31 μm, respectively, which were significantly higher than those of LAEW. The second phases of all components were mainly Al3(Sc1-x, Zrx) phases. Compared to LAEW, the Al3(Sc1-x, Zrx) phases of components with HAEW had a larger area fraction and average diameter, as well as a higher number density at the same process parameters, the highest values were around 3.00 %, 1.27 ± 0.89 μm, and 15.20 × 103 /mm2. Al3(Sc1-x, Zrx) phases could not only serve as the nucleation cores of bubbles but also hinder bubbles escape. In addition, the Sc element significantly increased the viscosity of Al melt. Therefore, the main influencing factors of pores in components with HAEW were not only process parameters, but also the Al3(Sc1-x, Zrx) phases. However, for LAEW, the process parameters were the major influencing factors on porosity due to lower area fraction and number density of Al3(Sc1-x, Zrx) phases. This work has laid a theoretical foundation for WA-DED-processed high-strength Al-Mg-Sc-Zr alloys.

Three‐dimensional‐printed Ni‐based scaffold design accelerates bubble escape for ampere‐level alkaline hydrogen evolution reaction

AbstractAlkaline hydrogen evolution reaction (HER) for scalable hydrogen production largely hinges on addressing the sluggish bubble‐involved kinetics on the traditional Ni‐based electrode, especially for ampere‐level current densities and beyond. Herein, 3D‐printed Ni‐based sulfide (3DPNS) electrodes with varying scaffolds are designed and fabricated. In situ observations at microscopic levels demonstrate that the bubble escape velocity increases with the number of hole sides (HS) in the scaffolds. Subsequently, we conduct multiphysics field simulations to illustrate that as the hole shapes transition from square, pentagon, and hexagon to circle, where a noticeable reduction in the bubble‐attached HS length and the pressure balance time around the bubbles results in a decrease in bubble size and an acceleration in the rate of bubble escape. Ultimately, the 3DPNS electrode with circular hole configurations exhibits the most favorable HER performance with an overpotential of 297 mV at the current density of up to 1000 mA cm−2 for 120 h. The present study highlights a scalable and effective electrode scaffold design that promotes low‐cost and low‐energy green hydrogen production through the ampere‐level alkaline HER.

Hollow NiMo-based nitride heterojunction with super-hydrophilic/aerophobic surface for efficient urea-assisted hydrogen production

Hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) are key reactions of the water-cycling associated catalytic process/device. The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise. Here, we have designed a three-dimensional (3D) hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a one-pot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process. The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07° and an underwater bubble contact angle of 155.7°, thus facilitating an escape of bubbles from the electrodes. Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN, which can promote the adsorption/desorption of reactants and intermediates. The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at 10 mA cm−2. The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm−2, which is approximately 209 mV lower than water electrolysis.

A comparative study on welding characteristics and mechanical properties of Ti–6Al–4V laser welded joints under the sub-atmospheric pressure and beam oscillation

Sub-atmospheric pressure environment and oscillation laser are both excellent ways to improve welded joint quality. However, the differences in their effects and mechanisms are unclear. Therefore, the differences between sub-atmospheric pressure and oscillating laser in weld formation, porosity suppression and grain size refinement were analyzed in this study. The results revealed that penetration depth of welded joint was increased to 6.09 mm under sub-atmospheric pressure environment while it was decreased to 3.3 mm under oscillation laser. Furthermore, reducing fluctuating vapor pressure and suppressing vortex formation were the main means to improve the keyhole stability and promote the escape of bubbles in a sub-atmospheric pressure environment. The improvement of the oscillating laser in these two aspects was attributed to enlarging keyhole area, shortening escape path and oscillation keyhole absorption. Additionally, the average grain size in the upper weld was reduced from 134.6 μm to 118.6 μm and 114.1 μm under the sub-atmospheric pressure environment and laser oscillation, respectively. The reduction of the temperature gradient led to former grain refinement while the increase of heterogeneous nucleation rate was responsible for latter grain refinement. Correspondingly, the mechanical properties of welded joints were improved. The study offered valuable insights for the application of laser welding with oscillation laser and sub-atmospheric pressure in industrial production.

The Impact of Decreased Atmospheric Pressure on Forced Aeration of Discharged Flow

To account for changes in the performance of spillway aerator structures of high-altitude dams, depressurization generalized model experiments and theoretical analyses were conducted in this study. Measurements were taken for ventilation hole air velocity, cavity subpressure, cavity length, and air concentration in crucial regions. The study proposed correction formulas for the aeration coefficient and water air concentration in aerator devices operating under low atmospheric pressure. The pressure range of the experiments was between 26.3 kPa and 101.3 kPa. The results indicated that with decreasing atmospheric pressure, ventilation hole air velocity, ventilation volume, cavity subpressure, and water air concentration all showed a decreasing trend. For every 15 kPa decrease in pressure, ventilation hole air velocity decreased by approximately 24%. When the atmospheric pressure dropped from 101.3 kPa to 26.3 kPa, the cavity subpressure decreased and eventually approached zero. The maximum reduction in air concentration was 14.9% in the cavity backwater area, 38.5% at the cavity end, and 38.3% in the downstream bubble escape segment. The proposed correction formulas could be used for a rapid estimation of ventilation volume and air concentration in low-pressure environments. This research provides a scientific basis for the design of aeration devices in water projects located in high-altitude regions.

Constructing Self-Supported electrode with superhydrophilicity and strong bubble escape ability surface for hydrogen evolution

The superhydrophilicity of the self-supported electrode surface and the bubble escape behavior at the interface have important effects on efficient hydrogen production. Herein, we fabricated self-supported electrodes with different structures based on carbon cloth (CC), consisting of Ni(OH)2 nanosheets (Ni(OH)2/CC), Ni nanoparticles (Ni/CC), and metal Ni encapsulated in carbon nanotubes (Ni@CNTs/CC), respectively. Among them, Ni@CNTs/CC shows the lowest overpotential of 190.1 mV at −10 mA cm−2 toward the hydrogen evolution reaction (HER) process. Ni@CNTs/CC exhibits an extremely low contact angle of 0°, demonstrating its superhydrophilicity nature. Moreover, the large contact angle (153°) and small dynamic bubble size (101 μm) at the Ni@CNTs/CC/electrolyte interface suggest a strong bubble escape ability.

Keyhole stability, arc behavior, and molten pool flow in narrow-gap oscillating laser-arc hybrid welding of titanium alloy

In the study, the keyhole stability, arc behavior and molten pool flow were investigated to clarify the welding process stability in narrow-gap oscillating laser-arc hybrid welding of titanium alloy. At an oscillating frequency of 300 Hz and amplitude of 1 mm, a concave weld with low porosity was produced. Compared with non-oscillating laser, the keyhole opening size increased about twofold, and the standard deviation of arc deflection angle differences decreased by approximately 87.6 %. Owing to the stirring effect of beam oscillation, a stable keyhole with larger opening size was formed, which facilitated the escape of bubbles from the keyhole. More excitation electrons were generated and erupted outward from the keyhole, and both plasma temperature and density increased by approximately 55.2 %. An enhanced electric channel was formed between the welding wire tip and groove center. As a result, the arc burnt stably at the groove bottom, which could melt the groove bottom synchronously, and suppress sharp corners and lack of fusion. The impact caused by droplets was cushioned as the liquid metal flowed towards the rear molten pool orderly with a circular path. Consequently, the liquid metal near the keyhole fluctuated slightly, indicating that the keyhole stability was enhanced. Besides, dendrites were fragmented and more equiaxed grains were produced due to the strong disturbance of dendrites by liquid metal in the whole mushy zone.

Effect of thermophysical properties on porosity and microstructure of laser welded cast and wrought aluminum alloy dissimilar lap joints

The influence of thermophysical properties of materials on the porosity and microstructure of dissimilar lap joints between laser-welded Al–Si–Mg cast and Al–Mg–Si–Cu wrought aluminum alloys was investigated. The low thermal conductivity and viscosity of the weld would promote bubble escape, while the high electrical conductivity of the base material would increase the melt depth and reduce the convection intensity in the melt pool, thus increasing the difficulty of bubble escape. The variation in thermophysical properties did not significantly impact the distribution of elements, the type of precipitated phases, and the dislocation density, however, it did affect grain morphology. Differences in thermal diffusion coefficients between base materials created conditions for constitutional supercooling, increasing the likelihood of a columnar-to-equiaxed transition. Moreover, the temperature difference between the liquid phase lines of the weld and base materials facilitated the liquid base material flushed into the weld to solidify before mixing, resulting in an “island” formation. This “island” acted as a heterogeneous nucleation site, leading to equiaxed grain layer formation in the lowest zone of the weld. The variations in thermophysical properties exerted an influence on the tensile strength by impacting both the melt depth and the grain morphology of the weld but did not yield a significant impact on the average microhardness.

Initial temperature of bubble formation at Oil-Paper interface based on bubble dynamics

The initiation of bubbles at the surface of insulating paper under high temperature may result in partial discharge and ultimately lead to the insulation failure of oil-immersed transformers. To study the formation mechanism of bubbles, the process of bubble growth at the oil-paper interface is established by using Rayleigh-Plesset equation. The Ideal Gas Law as well as the Hertz-Knudsen relation is used to quantify the flux of water vapor entering the bubble. The growth curve of bubbles in the oil-paper during temperature rise is calculated. And the Initial Temperature of Bubble Escape (ITBE) is then obtained based on the force analysis of the bubble growth. The results show that the bubble detaches from the surface of paper when its radius reach 198 μm, which is consistent with experimental observations. And the minimum average relative error between the predicted ITBE and experimental results is 1.11%. The effect of influence factors on the ITBE of oil/paper are then studied in detail. It is shown that the increased moisture content in paper accelerates the growth rate of bubbles, then reduces the ITBE. And the higher pressure inside oil tank restrains the bubble growth through the overall process. Additionally, as the cavity size of paper increase, the surface tension of bubble increases. Consequently, the bubbles require a larger size to achieve sufficient buoyancy for their escape from the aged paper.

Mechanism analysis on suppressing porosity in laser-MIG hybrid welding of aluminum alloy via external magnetic field

An external magnetic field with a high magnetic flux density (≥300 mT) has been proven to reduce the porosity of aluminum alloy single laser welded joints. However, the additional welding current exists in laser-arc hybrid welding (LAHW) and its physical mechanism of interaction between the external magnetic field and the molten pool is different from magnetic-assisted laser welding. It was explored whether the porosity suppression of the external magnetic field works in LAHW using experimental observation and numerical simulation. The results suggested that the presence of an arc would induce the interaction between the magnetic field with a lower magnetic flux density and welding current, giving rise to a strong backward Lorentz force up to 1.44 × 105 N/m3, which differed from that in the magnetic-field-assisted laser welding. Although the presence of an arc heat source extended the solidification time of the rear weld pool. The impact of the droplet on the rear keyhole wall deteriorated the keyhole stability and caused severe keyhole collapse. Additionally, some vortices also deformed the keyhole rear wall and prevented the escape of bubbles in LAHW, leading to a greater porosity rate of 13.7 %. However, the impact of the droplet was weakened and vortices were reduced when an external magnetic field of 24 mT was used, which significantly decreased the porosity rate of LAHW to 2.0 %. This study will provide a more underlying understanding of magnetic-field-assisted welding and widen the industrial application of LAHW.

Accelerating Gas Escape in Anion Exchange Membrane Water Electrolysis by Gas Diffusion Layers with Hierarchical Grid Gradients.

At high current densities, gas bubble escape is the critical factor affecting the mass transport and performance of the electrolyzer. For tight assembly water electrolysis technologies, the gas diffusion layer (GDL) between the catalyst layer (CL) and the flow field plate plays a critical role in gas bubble removal. Herein, we demonstrate that the electrolyzer's mass transport and performance can be significantly improved by simply manipulating the structure of the GDL. Combined with 3D printing technology, ordered nickel GDLs with straight-through pores and adjustable grid sizes are systematically studied. Using an in situ high-speed camera, the gas bubble releasing size and resident time have been observed and analyzed upon the change of the GDL architecture. The results show that a suitable grid size of the GDL can significantly accelerate mass transport by reducing the gas bubble size and the bubble resident time. An adhesive force measurement has further revealed the underlying mechanism. We then proposed and fabricated a novel hierarchical GDL, reaching a current density of 2 A/cm2 at a cell voltage of 1.95 V and 80 °C, one of the highest single-cell performances in pure-water-fed anion exchange membrane water electrolysis (AEMWE).

Accelerating Gas Escape in Anion Exchange Membrane Water Electrolysis by Gas Diffusion Layers with Hierarchical Grid Gradients

AbstractAt high current densities, gas bubble escape is the critical factor affecting the mass transport and performance of the electrolyzer. For tight assembly water electrolysis technologies, the gas diffusion layer (GDL) between the catalyst layer (CL) and the flow field plate plays a critical role in gas bubble removal. Herein, we demonstrate that the electrolyzer's mass transport and performance can be significantly improved by simply manipulating the structure of the GDL. Combined with 3D printing technology, ordered nickel GDLs with straight‐through pores and adjustable grid sizes are systematically studied. Using an in situ high‐speed camera, the gas bubble releasing size and resident time have been observed and analyzed upon the change of the GDL architecture. The results show that a suitable grid size of the GDL can significantly accelerate mass transport by reducing the gas bubble size and the bubble resident time. An adhesive force measurement has further revealed the underlying mechanism. We then proposed and fabricated a novel hierarchical GDL, reaching a current density of 2 A/cm2 at a cell voltage of 1.95 V and 80 °C, one of the highest single‐cell performances in pure‐water‐fed anion exchange membrane water electrolysis (AEMWE).