Performance Of Electrolyte Research Articles

Superhydrophilicity and Electronic Modulation on Self-Supported Lignin-Derived Carbon Coupled with NiO@MoNi4 for Enhancing Urea Electrolysis.

Developing highly efficient biomass-derived carbon-based electrocatalysts remains challenging for urea electrolysis because most of these electrocatalysts show powder morphology, which can lead to Ostwald ripening during the reaction process, and its reaction mechanism should be further verified. Herein, self-supported lignin-derived carbon coupling NiO@MoNi4 heterojunction (NiO@MoNi4/C) possesses superhydrophilic properties and electronic modulation, boosting the performance of urea electrolysis. Electrochemical results show that an indirect oxidation step for urea oxidation reaction (UOR) and Volmer-Heyrovsky mechanism for hydrogen evolution reaction (HER) occurs on the surface of NiO@MoNi4/C. It displays low potentials for UOR (E10/500/1000 = 1.28/1.41/1.47 V) and for HER (E-10/-500/-1000 = -38/-264/-355 mV) in 1.0 MKOH + 0.5M urea electrolyte solution. The good activity is ascribed to the self-supported lignin-derived carbon and heterojunction, which increases the number of active sites, optimizes electronic structure, and improves electron transfer. Benefiting from the self-supported lignin-derived carbon, NiO@MoNi4/C demonstrates corrosion resistance and superhydrophilicity, which avoids Ostwald ripening and accelerates gas-liquid transfer, thus, maintaining for 100 h at ±1000/±1500 mA cm-2 during the UOR and HER test. This work provides a good catalyst for urea electrolysis and presents a promising way for preparing lignin-derived carbon-based catalysts while expanding the application of lignin-based biomass carbon materials.

Insights into the Electrochemical Oxidation and Reduction of Nickel Oxide Surfaces.

Surface oxidation/reduction processes, driven by varying electrochemical potentials, can substantially impact catalyst effectiveness and, consequently, electrolyzer performance. This study combines theoretical and experimental approaches to explore the surface redox behavior of nickel oxides, which are cost-effective and efficient catalysts for many electrochemical reactions. Surface Pourbaix diagrams for three different phases of nickel oxides, i.e., nickel hydroxide (Ni(OH)2), nickel oxyhydroxide (NiOOH), and nickel dioxide (NiO2), were constructed using density functional theory-based simulations. Various experimental methods, including cyclic voltammetry, in situ Raman spectroscopy, and electrochemical titration, were employed to probe the surface redox processes of nickel oxide thin films. Our findings indicate that the ABAB stacking sequence of Ni(OH)2 lacks stability under oxidizing conditions to host the surface oxidation (deprotonation) events, while the AABBCC stacking sequence of NiOOH is energetically favorable due to the presence of interlayer hydrogen bonding. Rapid charge transfer facilitated by interlayer hydrogen bonding accounts for the higher reactivity of partially oxidized/reduced NiOOH (001) surfaces compared to Ni(OH)2 (001) and NiO2 (001) surfaces with the same stoichiometry, where interlayer hydrogen bonding is absent. Insights presented in this work can offer guidelines for optimizing operational conditions and tailoring the surface structures and oxidation states of nickel oxides to enhance performance in applications such as electrocatalysis and supercapacitors.

Effect of Anion-Conducting Electrolytes in Pore-Filling Membranes on Performance and Durability in Water Electrolysis

This study examines the effect of the structural characteristics of anion-conducting monomers within pore-filling anion exchange membranes on the performance and durability of anion exchange membrane water electrolysis. Analysis reveals that acrylamide- and acrylate-based membranes show optimal performance without methyl groups, with acrylamide-based membranes outperforming their acrylate counterparts in current density, particularly at 1.8 V. The AC-AA and AC-MAA monomers demonstrate durability, with AC-MAA showing enhanced alkaline stability, likely due to the presence of a methyl group, resulting in an increase rate of 746.6 μV/h compared to AC-AA’s 1150 μV/h. This study also shows that a commercial membrane exhibits a decrease rate of 3116 μV/h, underscoring the pore-filling membrane’s superior durability. Furthermore, the findings highlight that pore-filling membrane technology enables better durability and performance in electrolysis environments compared to the commercial homogeneous membrane, particularly when alkaline conditions are present. This research provides a foundation for designing high-performance, durable membranes for efficient hydrogen production, particularly under water electrolysis conditions.

Life cycle environmental impacts and costs of water electrolysis technologies for green hydrogen production in the future

BackgroundTo limit climate change and reduce further harmful environmental impacts, the reduction and substitution of fossil energy carriers will be the main challenges of the next few decades. During the United Nations Climate Change Conference (COP28), the participants agreed on the beginning of the end of the fossil fuel era. Hydrogen, when produced from renewable energy, can be a substitute for fossil fuel carriers and enable the storage of renewable energy, which could lead to a post-fossil energy age. This paper outlines the environmental impacts and levelized costs of hydrogen production during the life cycle of water electrolysis technologies.ResultsThe environmental impacts and life cycle costs associated with hydrogen production will significantly decrease in the long term (until 2045). For the case of Germany, the worst-case climate change results for 2022 were 27.5 kg CO2eq./kg H2. Considering technological improvements, electrolysis operation with wind power and a clean heat source, a reduction to 1.33 kg CO2eq./kg H2 can be achieved by 2045 in the best case. The electricity demand of electrolysis technologies is the main contributor to environmental impacts and levelized costs in most of the considered cases.ConclusionsA unique combination of possible technological, environmental, and economic developments in the production of green hydrogen up to the year 2045 was presented.Based on a comprehensive literature review, several research gaps, such as a combined comparison of all three technologies by LCA and LCC, were identified, and research questions were posed and answered. Consequently, prospective research should not be limited to one type of water electrolysis but should be carried out with an openness to all three technologies. Furthermore, it has been shown that data from the literature for the LCA and LCC of water electrolysis technologies differ considerably in some cases. Therefore, extensive research into material inventories for plant construction and into the energy and mass balances of plant operation are needed for a corresponding analysis to be conducted. Even for today’s plants, the availability and transparency of the literature data remain low and must be expanded.

Effect of SS 316, SS 304 and Carbon Steel Electrodes on the performance of homemade electrolyzer, microstructural changes and corrosion characteristics during Green Hydrogen Production

Effect of SS 316, SS 304 and Carbon Steel Electrodes on the performance of homemade electrolyzer, microstructural changes and corrosion characteristics during Green Hydrogen Production

MXene-supported 2D bimetallic chalcogenide electrocatalyst: Enhanced electrochemical seawater splitting

Hydrogen energy holds immense potential for revolutionizing modern energy technologies. Seawater electrolysis is a promising strategy for hydrogen production; however, the lack of effective electrodes limits its widespread application. Therefore, developing high-performance, cost-effective catalysts for water splitting is essential for sustainable energy conversion. In this context, we report a novel hybrid bimetallic selenide (CoMoSe2) and MXene (Ti3C2Tx) electrocatalyst, which exhibits remarkable catalytic performance for seawater electrolysis. The CoMoSe2@Ti3C2Tx electrocatalyst demonstrates outstanding catalytic capabilities, achieving overpotentials of 82 mV for hydrogen evolution reaction (HER) and 329 mV for oxygen evolution reaction (OER) at a current density of 10 mA cm⁻2 in alkaline conditions. The Tafel slope values are 124 mV dec⁻1 for hydrogen evolution and 69 mV dec⁻1 for oxygen evolution, outperforming their individual components. The enhanced bifunctional catalytic performance of the hybrid catalyst is attributed to the synergistic effect of Mo atoms within the CoSe2 crystal structure, which modifies the electronic structure and lowers the chemisorption energies of hydrogen and oxygen intermediates. The abundance of oxygen vacancies provides more reactive active sites and improves electrical conductivity. Additionally, the CoMoSe2@Ti3C2Tx composite has demonstrated remarkable bifunctional electrocatalytic performance for seawater splitting, achieving 10 mA cm⁻2 at overpotentials of 161 mV for HER and 354 mV for OER in alkaline seawater. The Volmer-Heyrovsky mechanism drives the remarkable long-term stability of the catalyst. This novel approach contributes to sustainable energy solutions by providing a fresh avenue for the development of effective catalysts to produce hydrogen from seawater.

Anion exchange membrane electrolysis at work—Investigating impact of starting parameters and start-stop operation on cold start behavior and degradation

Water electrolysis is a key technology for the production of green hydrogen, with anion exchange membrane water electrolysis (AEMWE) showing promising properties. Future energy systems will require transient electrolysis operation to combine electrolysis with fluctuating renewably generated power. This study examines and optimizes the cold start process (ambient temperature and 0 V stack voltage) of an AEMWE stack system in terms of starting time, energy demand and degradation. The influence of relevant parameters such as voltage slope, target voltage, downtime and heating strategy on the starting process is experimentally quantified. A temporary increase in cell voltage during the starting process thereby represents a suitable compromise between acceleration of the startup and maintaining a low degradation. In addition, the start-stop degradation analysis with 150 cold starts per parameter set reveals that the degradation of the AEMWE stack during the starting process is independent of the maximum cell voltage and instead correlates with the steepness of the current slope. Using electrochemical impedance spectroscopy, the degradation is assigned to electrode processes. Under moderate starting conditions, degradation rates of 2–10 μV start−1 are observed. This shows that AEMWE is highly compatible with regular operational interruptions.

Numerical modeling of two-phase flow considering multiple bubble sizes in an alkaline water electrolyzer

Precise bubble flow description is crucial for predicting water electrolysis performance. This study employs the Euler-Euler model to simulate bubble flow in an alkaline water electrolysis cell, categorizing the dispersed gas bubble phase into three size classes: 30 ▪ (small), 90 ▪ (medium), and 270 ▪ (large). The volume fraction and velocity fields for each size class were simulated across three current densities, revealing distinct flow patterns: large bubbles exited directly through the outlet, while smaller bubbles were carried along by the circulating liquid. The simulated flow fields were compared with experimentally visualized flow fields, validating the model. Finally, the proposed model demonstrated its advantages over existing models, such as the monodispersed model and the population balance model (PBM), particularly in terms of upward flow velocity near the electrode and bubble descending height in the downward flow.

In Situ Self-Assembled 200nm-Depth Highly Active Layer Non-Precious Metals Catalyst for Industrial Water Electrolysis.

Nickel-based electrocatalysts are promising for industrial water electrolysis, but the dense hydroxyl oxide layer formed during the oxygen evolution reaction (OER) limits active sites accessibility and presents challenges in balancing structural stability with effective charge transfer. Based on this, an efficient in situ leaching strategy is proposed to construct grain boundary-rich catalyst structure with high charge transfer ability and a deep catalytic active layer reached >200-nm. Under OER conditions, stable sub-nano Ni3Al particles are embedded in Ni(Fe)OOH, originating from leaching out the unstable Ni2Al3 phase of the initial Ni2Al3/Ni3Al alloy doped with Fe. The structural evolutions are characterized using in situ Raman spectroscopy, transmission electron microscopy, and X-ray absorption spectroscopy. The catalyst exhibits exemplary performance, evidenced by a low overpotential of 212mV at 10mAcm-2, a minimal Tafel slope of 25.0mVdec-1. The catalyst maintains stable for >500h at 500mAcm-2 under industrial conditions. Furthermore, its performance in seawater electrolysis is notably superior, exhibiting an overpotential of 223mV at 10mAcm-2 and a Tafel slope of 37.5mVdec-1. The in situ high activity in the deep porous phase by leaching out unstable phases provides a new method for engineering high-performance industrial catalysts.

Ga-Based Ga@In4Ag9/Cu for CO2 Electroreduction to CO in a Three-Chamber Electrolyzer: With NaOH and Cl2 as Byproducts.

Electroreduction of carbon dioxide (CO2RR) using renewable energy offers a sustainable approach for generating valuable chemicals. In this study, a three-chamber electrolyzer was utilized for the direct coproduction of CO, Cl2, and NaOH from CO2 and NaCl electrolysis, contributing to net CO2 consumption and supporting industries like phosgene synthesis. To improve the electrolyzer performance, a Ga-based metal composite catalyst (Ga@In4Ag9/Cu) was developed. This catalyst efficiently reduced CO2 to CO during long-term electrolysis, achieving a CO partial current density of 147.16 mA·cm-2 and a faradaic efficiency of 93.1% at -2.4 V (vs SHE). Density functional theory (DFT) calculations revealed that Ag atoms modulate the d-band center of Ga@In4Ag9/Cu, enhancing its interaction with the reaction intermediates. This work introduces a Ga-based porous catalyst for CO2 electrolysis in organic electrolytes, offering a promising system for the coproduction of CO, Cl2, and NaOH through a coupled reaction.

Understanding the Mechanism of Evaporation-Induced Islands during the Formation of Catalyst Layers and Their Influence on the Alkaline Oxidation Evolution Reaction

Advancements in anode development substantially reduce the cost and enhance the performance of water electrolysis. The strategic configuration of nano-sized catalyst materials on anode supports is a pivotal factor in the expansion of the production of catalyst layers and has a significant influence on their electrochemical performance [1–3]. Therefore, it is essential to understand the structure formation mechanisms during electrode fabrication. This contribution aims to explore the inherent drying mechanisms in the coating process and their subsequent influence on the morphological evolution of anodes, ultimately establishing a linkage between these morphological changes and electrochemical performance and stability metrics. The initial phase of the study involved a detailed characterization of commercial nickel cobalt oxide nanoparticles via advanced analytical techniques, including transmission electron microscopy and energy-dispersive X-ray spectroscopy [4]. Subsequently, a stable ink was formulated by dispersing the catalyst alongside a binder in a solvent, which was then uniformly applied to a conductive nickel plate utilizing an ultrasonic spray coater. Prior to application, the catalyst inks underwent optimization based on the Hansen solubility parameters of catalyst materials [5, 6] and subsequent visualization of their stability and dispersibility characteristics through transmittogram analysis [7]. The drying process of the coating was conducted at two distinct temperatures, 50 °C and 150 °C, to investigate the effect of temperature on solvent evaporation. Morphological and structural analyses of the anodes were subsequently performed using scanning electron microscopy (SEM), laser scanning microscopy (LSM), and atomic force microscopy (AFM), providing insight into the alterations induced by the drying process. The analyses conducted in this study elucidate significant modifications in the morphology of the layer structures attributable to variations in drying temperatures as illustrated in Figure 1. Specifically, lower temperature resulted in reduced evaporation rates that facilitated the formation of larger, isolated regions/islands on the anode support. These are indicative of a non-uniform coating distribution. In contrast, a higher temperature promoted rapid evaporation, resulting in a quite homogeneous distribution of smaller islands accompanied by the emergence of voids within the anode layer. Electrochemical analysis revealed that these morphological changes are of vital importance: they govern the wetting behaviour and the dynamics of bubble formation which are important for the electrochemical performance and durability of the catalyst layers. Moreover, the insights gleaned from this study are instrumental in identifying optimal configurations of catalyst layer structures, i.e., features that should be maintained during scale-up. In conclusion, this study significantly advances the field by revealing novel principles governing the design and optimization of electrode structures for the oxygen evolution reaction. In particular, the complicated relationship between drying temperatures and morphological evolution, which significantly influences electrochemical performance is explained.

Impact of cell design and conditioning on polymer electrolyte membrane water electrolyzer operation

Integration of polymer electrolyte membrane water electrolyzers (PEMWEs) for clean hydrogen generation requires a robust understanding of the impact cell designs and conditioning protocols have on operation and stability. Here, catalyst-coated electrode and catalyst-coated membrane cells employing Pt/C cathode catalyst layer, an IrO2 anode catalyst layer, with a platinized titanium mesh or a carbon paper with a microporous layer as the porous transport layer were developed. The impact of cell conditioning above and below 0.25 A cm−2 was investigated using advanced electrochemical impedance spectroscopy analyses and microscopic imaging, with the electrochemical response related to physicochemical processes. Operation below 0.25 A cm−2 prior to operation above 0.25 A cm−2 resulted in anode corrosion and titanium cation contamination, increasing the cell voltage at 1 A cm−2 by 200 mV compared to uncontaminated cells. Conditioning above 0.25 A cm−2 led to non-negligible hydrogen transport resistances due to cathode flooding that resulted in a ca. 50 mV contribution at 1 A cm−2 and convoluted with the anode impedance response. The presence of a microporous layer increased catalyst utilization but increased the cell voltage by 300 mV at 1 A cm−2 due to increased anodic mass transport resistances. These results yield critical insights into the impact of PEMWE cell design and operation on corresponding cell performance and stability while highlighting the need for application dependent standardized operating protocols and operational windows.

Enhancing solid oxide electrolysis cell cathode performance through defect and bond engineering: A study on K-doped PrBaMn2O5+δ perovskites

Collaborative design of defects and bonds is a novel strategy to enhance the activity of cathode materials for solid oxide electrolysis cells (SOECs). In this study, we report the synthesis and characterization of layered PrBaMn2O5+δ (PBM) and Pr0.9K0.1BaMn2O5+δ (PKBM) materials, aimed at developing cathodes for high-temperature H2O electrolysis. The effects of K doping on the structural, physicochemical, and electrochemical properties of these materials are thoroughly investigated. The results reveal that K doping induces lattice expansion and reduces the total cation valence state in PKBM. These changes significantly increase oxygen vacancy concentration, enhancing the chemical adsorption capacity of H2O on the electrode surface and improving the H2O reduction reaction activity. Theoretical calculations support these findings, showing that K doping lowers the oxygen vacancy formation energy and strengthens H2O adsorption. Impedance analyses further demonstrate that K doping reduces the polarization resistance, thereby enhancing surface adsorption and diffusion processes. Consequently, the PKBM cathode exhibits superior electrolysis performance, achieving a current density of 739 mA/cm2 at 1.3 V and 800 °C. This strategy provides valuable insights for designing advanced cathodes for high-temperature H2O electrolysis and other electrochemical catalysis applications.

Experimental study of performance enhancement in PEMEC with titanium mesh flow structure via in-situ temperature measurement

A proton exchange membrane electrolysis cell (PEMEC) is a promising method for hydrogen production. However, the flow-field structure of PEMEC presently has the disadvantages of poor fluidity and uneven heat distribution. A titanium mesh flow field was, therefore, proposed to replace the traditional parallel channel structure. A single-cell test platform was set up in this study, and a new in situ temperature measurement method was proposed. The temperature variation and electrolysis performance of titanium mesh structures were studied experimentally. The results demonstrated that the polarization performance of the titanium mesh structure was enhanced compared to that of the parallel structure. In situ measurements showed that the temperature increased and the voltage decreased with an increase in the inlet temperature and flow rate, with the rate of change gradually decreasing. The temperature distribution in the titanium mesh structure was more uniform than that in the parallel structure. When the current density and inlet flow rate step were changed, the voltage stabilized within 12 s. After 100 h of operation, the voltage of the parallel structure and titanium mesh structure increased by 0.12 V and 0.07 V, respectively, indicating good dynamic and duration performance.

Synergistic effect of FeOOH cocatalyst and Al2O3 passivation layer on BiVO4 photoanode for enhanced photoelectrochemical water oxidation

BiVO4 is one of the most attractive photoanodes for water oxidation due to its 2.4 eV narrow band gap, suitable band edge position, good stability in aqueous solution, low cost and non-toxicity. However, due to some inherent disadvantages such as low carrier mobility, severe charge recombination and slow water oxidation kinetics, the actual BiVO4 photocurrent density is often lower than the theoretical value of 7.5 mA cm−2. In this paper, BiVO4 was modified by alkali-treated Al2O3 passivation layer and FeOOH, and the photocurrent density of BiVO4 reached an astonishing 3.8 mA cm−2 at 1.23 VRHE, and the ABPE (applied bias photon-to-current efficiency) was close to 1 %. The detailed structural characterization and electrochemical test show that Al2O3 prepared by ALD (atomic layer deposition) can play a role in passivation of BiVO4 surface state after alkali treatment, inhibit electron hole recombination on BiVO4 surface, and accelerate hole transfer. As a hole storage layer and catalyst layer, FeOOH promoted the interfacial hole transfer, increased the active sites at the electrode electrolyte interface, and significantly increased the water oxidation activity. This work provides a novel method to enhance the performance of water electrolysis by using ALD to assist passivation of bismuth vanadate photoanode surface states.

Study on the influence characteristics of multi-working condition parameters on membrane electrode type CO2 electrolyzer

The electrochemical conversion of carbon dioxide (CO2) into basic chemicals or carbon-based fuels is a promising new strategy for carbon resource utilization. Within this domain, solid-electrolyte CO2 electrolyzer demonstrate significant potential for the continuous production of pure formic acid solutions. This study, leveraging a 4 cm2 visualization electrolyzer, explores the impact of three working condition parameters on performance: working voltage, gas flow rate, and the intermediate chamber water flow rate. It compares the variations in current density, formic acid concentration, and the distribution of liquid water on the cathode side under different working conditions. The results indicate that the working voltage, current density, and formic acid yield are all positively correlated; overly low gas flow rates can lead to CO2 deficiency and diminished electrolyzer performance; concentration control of the formic acid solution is effectively achieved by adjusting the intermediate chamber water flow rate; and during the electrolyzer reaction process, almost all of the liquid water is positioned at the bends downstream of the cathode flow channel.

Utilizing electrooxidation for textile effluent wastewater treatment and simultaneous electrocatalytic hydrogen production: Transforming waste into energy and promoting water reuse in a circular economy context

Textile effluent wastewater poses a serious environmental risk because of its high concentration of pollutants, which include organic compounds, heavy metals, and dyes. The present study investigates the technical and economic feasibility of hybrid water electrolysis performances. Specifically, real textile effluent wastewater was utilised to examine simultaneous abatement and electrochemical hydrogen production. The treated water can be recycled in the textile mill, offering the benefits of trash-to-treasure and cost savings through the circular economy. In addition to reducing the environmental impact of textile wastewater, the synergistic approach seeks to maximise its potential for producing hydrogen as clean energy. Here, the commercially available stainless sheet was used as the anode in the electrochemical setup system and the two-dimensional Ti3C2TX MXene was used as the catalyst embedded cathode. The optimal electrode-electrolyte parameter settings resulted in an 83 % decrease in COD level and a degradation efficiency of about 88 %. The potential for widespread adoption in the textile industry is highlighted by the discussion of the economic viability and environmental advantages of using wastewater from textile effluents for pollutant degradation and hydrogen production. Hence, the energy estimation was looked at and estimated in order to evaluate the process viability. For instance, the hybrid electrolysis process uses a very small amount of electricity (0.825 kWh m−3 order−1) and has an apparent operating current (30 mA/cm2). This work could serve as a guide for the methodical assessment and choice of hybrid water electrolysis using actual wastewater. The electrode's recyclability and reuse were proven for possible commercial applications. The stability of the Ti3C2TX electrode over a wide pH range was investigated in order to produce hydrogen on a big scale at a reasonable cost.

Effects of gravity on the cell performance of proton exchange membrane water electrolyzer

Hydrogen is of great significance for building a low-carbon and safe energy system. The proton exchange membrane water electrolyzer (PEMWE) is considered a highly promising hydrogen production device. However, due to the complex physical and chemical processes within the cell, and the impact of gravity effect on the cell characteristic is unclear. Analyzing the impact of gravity on cell performance is critical. In this study, the three-dimensional two-phase flow models are developed for the PEMWE, the models couple many physical fields, including the hydrodynamics, electrochemical reaction kinetics, mass transfer, heat transfer, two-phase flow based on Euler model, and gravity effect. The simulation model is verified through experiment results. The effect of gravity on the cell performance is investigated, the influences of gravity under different placement directions are compared, and the impact of the cell voltage on the transport characteristics is discussed under the gravity effect. Results show that the gas transport and heat transfer are enhanced under the gravity, the active sites in the catalytic layer can be timely released due to the accelerated bubble removal, the polarization performance is accordingly improved. The cell performance with the gravity effect under vertical placement is higher than that with the gravity effect under horizontal placement because of the improved mass transfer, but the mixture velocity at anode flow channel is decreased. Moreover, as the cell voltage increases, the electrochemical reaction rate is enhanced, the heat transfer is increased, and the volume fraction of disperse phase in anode flow channel is accordingly increased. This study provides a theoretical reference for further investigating transport characteristics and optimising the cell performance.

Enhanced Oxygen Evolution Reaction Performance of NiMoO4/Carbon Paper Electrocatalysts in Anion Exchange Membrane Water Electrolysis by Atmospheric-Pressure Plasma Jet Treatment.

NiMoO4 was grown on carbon paper (CP) by a hydrothermal method. A rapid and high-temperature atmospheric-pressure plasma jet (APPJ) process was used to generate more oxygen-deficient NiMoO4 on the CP surface to serve as an electrode material for the oxygen evolution reaction (OER). After 60 s of APPJ treatment, the overpotential of the electrode at 100 mA/cm2 decreased to 790 mV and that at 10 mA/cm2 decreased to 368 mV. Additionally, the charge transfer resistance decreased from 2.8 to 1.2 Ω, indicating that APPJ treatment effectively reduced the electrode overpotential and impedance. The effect of NiMoO4/CP/APPJ-60 s on the anion exchange membrane water electrolysis (AEMWE) system was also tested. At a system temperature of 70 °C and current density of 100 mA/cm2, the energy efficiency reached 95.1%, and the specific energy consumption decreased from 4.02 to 3.83 kWh/m3. These results demonstrate that the APPJ-treated NiMoO4/CP electrode can effectively enhance the OER performance in water electrolysis and improve the energy efficiency of the AEMWE system. This approach shows promise in replacing precious metal electrodes, thereby potentially reducing the cost and providing an environmentally friendly alternative.

Optimization of titanium alloy bipolar plate performance in proton exchange membrane water electrolysis with Cr/W/diamond-like carbon coating

The operating environment for bipolar plates in proton exchange membrane water electrolysis (PEMWE) systems is highly challenging, characterized by high electrical potential, acidic pH, and elevated temperatures. Bipolar plates must possess high corrosion resistance and electrical conductivity to ensure stable and efficient system perfomance. Therefore, surface coatings are essential to decelerate oxidation on the substrate surface, preventing a significant increase in interfacial contact resistance (ICR). This investigation applied a Cr/W/diamond-like carbon (DLC) coating to titanium alloy (Ti-6Al-4 V, also known as TC4) surfaces using magnetron sputtering. The multilayer coating system was designed to enhance electrical conductivity and corrosion resistance of the bipolar plate while ensuring good coating adhesion. At potentials of 1.2 V, 1.5 V, and 1.8 V, the current densities measured during potentiostatic polarization were 0.11 μA·cm-2, 0.19 μA·cm-2, and 0.4 μA·cm-2, respectively, showing a significant reduction compared to the TC4 matrix and demonstrating long-term stability. The Cr/W/DLC-coated TC4 bipolar plates exhibited an ICR of 16.98 mΩ/cm2 under a contact pressure of 1.4 MPa. These results suggest that the coating provides exceptional corrosion resistance under PEMWE operating conditions while retaining electrical conductivity.