Cathode Plate Research Articles

Performance of carbon felt as cathodes in magnesium corrosion method to recover phosphate from swine wastewater

With the large-scale development of the livestock and poultry breeding industries, swine wastewater with high nitrogen and phosphorus concentrations has become an urgent problem. Given the continuous demand for phosphorus resources in industrial production, the study of phosphate recovery in phosphorus-rich wastewater is of great value for the sustainable utilization of phosphorus resources and for alleviating the eutrophication of aquatic ecosystems. In this study, a magnesium metal corrosion method was used to recover phosphorus resources from swine wastewater using carbon felt as the cathode instead of traditional cathode materials such as graphite and titanium plates. The effects of different cathode materials on the corrosion potential of magnesium metal plates were compared, and the effects of carbon felt as a cathode plate on the removal rate and pH of phosphate from wastewater were discussed. Additionally, the economic feasibility of phosphate recovery from swine wastewater was evaluated. The experimental results showed that the effect of carbon felt on the corrosion potential of the magnesium metal plate was more evident than that of the graphite and titanium plates (Ecorr = −1.74676). When carbon felt was used as the cathode plate, the most energy-saving reaction conditions were as follows: reaction time T = 30 min, ratio of wastewater volume to plate area V: S = 500 cm3:50 cm2, aeration rate Re = 8 L/min, stirring rate r = 400 rpm, phosphate recovery rate = 92.3%, and pH = 8.83. The economic feasibility assessment shows that the proposed method is $2.047 g-1 PO4-P without considering the reuse of carbon felt. Carbon felt has good stability and can be recycled eight times or more, and the proposed method achieves a more efficient phosphate recovery rate at a relatively low cost.

Failure analysis of ternary lithium-ion batteries throughout the entire life cycling at high temperature

The operation life is a key factor affecting the cost and application of lithium-ion batteries. This article investigates the changes in discharge capacity, median voltage, and full charge DC internal resistance of the 25Ah ternary (LiNi0.5Mn0.3Co0.2O2/graphite) lithium-ion battery during full life cycles at 45 °C and 2000 cycles at 25 °C for comparison. The batteries before and after cycling were disassembled, and the structure, morphology, interface characteristics, element content of the cathode and anode plates of the battery were characterized. By analyzing the failure factors of the performance of the ternary batteries during the 45 °C cycling, a reaction mechanism for the rapid decline of high-temperature cycling performance of ternary batteries has been proposed. The results show that the performance degradation of the ternary lithium-ion batteries in the whole life operated at high temperature is characterized by slow decline in the initial stage and rapid drop in the latter stage. Further analysis of physical and chemical performance revealed irreversible damage to both the cathode and anode. The dissolution of transition metal ions from the cathode and their deposition on the anode surface catalyze the decomposition of electrolyte solvents to produce a large amount of gas. Gassing, accompanied by the deposition of Li2CO3 and the thickening of SEI, leads to an increase in the internal resistance of the battery. The coupling between gassing and increased internal resistance is responsible for the rapid drop in the performance of the ternary batteries during high-temperature cycling.

Electrochemically activated persulfate combined with tannic acid significantly improved sludge-dewatering performance: Sludge floc weight structure, Fe(II)/Fe(III), and organic component conversion

Sludge-dewatering effect is a key factor in sludge disposal. In this study, the conditioning system of electrochemically activated persulfate combined with tannic acid (EF-PDS/TA) was used to improve sludge-dewatering performance. Results showed that the sludge water content (Wc) and Specific resistance to filtration (SRF) decreased by 29.4 % and 93.3 %, respectively, under the optimal operating conditions, which significantly improved the sludge-dewatering effect. Through research, we found that SO4•− and ·OH were the main factors promoting the improvement in sludge-dewatering performance. After the reaction, the physicochemical properties of the sludge changed significantly, and the floc structure effectively cracked. Further analysis of Fe2+/Fe3+ conversion, EEM and FTIR showed that in the process of sludge conditioning, on the basis of EF promoting Fe2+/Fe3+ conversion through electron transfer between cathode and anode plates, TA addition further improved the conversion efficiency of Fe2+/Fe3+. The conversion rate was as high as 90 %, which improved the oxidation ability of sludge. The thermal energy generated by the EF ohmic heat effect can promote the complexation and precipitation of proteins in EPS by TA, and the energy can be effectively utilized. Moreover, EF and TA exerted a synergistic effect in promoting Fe2+/Fe3+ conversion and protein cleavage. Finally, the economic cost of the combined conditioning system was calculated, and the practical application value of the conditioning system was evaluated. The findings laid a theoretical foundation for further research in the field of advanced sludge oxidation.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

Modeling the Effect of Cell Orientation on the Performance of an Air-Breathing Polymer Electrolyte Fuel Cell with a Columnar Cathode Plate

Air-breathing polymer electrolyte fuel cells (PEMFCs) are expected to play an important role in the development of sustainable portable and mobile devices, such as unnamed aerial vehicles, motorbikes or laptops. In this work, the performance of air-breathing PEMFCs with a columnar cathode plate design is examined by means of a 3D two-phase, non-isothermal model, and compared against experimental data. The results show that the performance is highly influenced by the cell orientation, namely horizontal (material plane perpendicular to gravity) versus vertical (material plane parallel to gravity). Oxygen transport in horizontal cells is mainly dominated by diffusion, leading to oxygen shortage toward the cell center and an inhomogeneous current density distribution. In contrast, oxygen transport in vertical cells is assisted by natural convection, enhancing oxygen transport throughout the cell and increasing the current density homogeneity. Water saturation is preferentially accumulated close to the cell center, being larger in horizontal cells due to the lower water removal rate of the cathode plate.

A practical method for the in-situ estimation of the effective thermal resistance of gas diffusion layers in PEMFC

The membrane electrode assembly of a PEM fuel cell is hotter than the gas feeding plates because heat is generated within it, and the diffusion layers are thermally resistive. The temperature gradient created, which increases as a function of the current density, is useful for evacuating the water produced in vapor form. This water transport mechanism is known as the “heat pipe effect”. The temperature gradient produces a saturation vapour pressure gradient, which in turn produces a diffusive vapor flow. Mastering water management, coupled with heat management, requires knowledge of the temperature of the MEA and therefore the effective thermal resistance of the diffusion layers. In this paper, we present an original method for estimating this thermal resistance in situ, without using heat flux sensors or directly measuring the temperature of the MEA. The method requires the ability to impose a temperature gradient between the anode and cathode plates, and to perform a hot-side water balance. Thermal resistance is deduced from the coupling between heat and water transfer. Two diffusion layers widely used by the community are tested. The GDL Sigracet 22 BB (from SGL Carbon) has a lower effective thermal resistance than the GDL Freudenberg H15C14. Variations in these thermal resistances are measured as a function of the temperature gradient imposed and of the compression ratio.

Role of oxidants in the anodic oxidation of 2024 aluminum alloy by dominating anodic and cathodic processes

The addition of oxidants into the electrolyte of Al anodic oxidation can alter the anodic and cathodic reactions, further affects the quality of the oxide film. In this paper, the role of two typical oxidants of H2O2 and Na2MoO4 in the microstructure and corrosion resistance of the oxide film on 2024 aluminum alloy was investigated by the scanning electron microscopy (SEM), Mott Schottky plots and electrochemical impedance spectroscopy (EIS). The addition of H2O2 increases the oxygen evolution amount on the anode Al and more oxygen can participate in the oxide film formation to improve the compactness. The addition of Na2MoO4 results in the deposit of MoO2 on the cathode plate to accelerate the hydrogen evolution reaction by the catalytic action of the MoO2, which further accelerates the anodic reaction to form a thick oxide film. As a result, the corrosion resistance of the oxide film is significantly improved by adding H2O2 or Na2MoO4 due to the promotion of film thickness and compactness.

Research on the mechanism of copper removal during electromagnetic enhanced aerobic fermentation of sludge

The migration and transformation of copper during magneto electric assisted aerobic fermentation were studied by establishing a control group, a magnetic assisted group (1.4 mT), an electric assisted group (10 V), and a magneto electric assisted group. The results showed that during the aerobic fermentation process of magnetic assisted sludge, changes in pH, temperature, and microorganisms in the system promoted the dissolution of Cu2+ and its migration from solid sludge to fermentation broth. Due to the presence of an electric field, Cu2+ deposits on the cathode plate through anisotropic attraction, combined with the Lorentz force generated by the magnetic field, promoting mass transfer of copper ions and reducing the concentration of Cu2+ in the fermentation broth, resulting in a copper removal rate of up to 75 %. In addition, the COMSOL simulation results show a consistent overall trend with actual experiments, indicating that the external electric and magnetic fields have a significant inhibitory effect on the removal of heavy metals in sludge.

Comprehensive aging model coupling chemical and mechanical degradation mechanisms for NCM/C6-Si lithium-ion batteries

The aging of lithium-ion batteries (LIBs) is synergistically influenced by multiple chemical/mechanical degradation mechanisms. Therefore, conventional models that incorporate only partial mechanisms exhibit limited predictive accuracy and applicability, failing to fully reflect the effects of chemical/mechanical degradation under complex operating conditions. Here, we propose an aging model for NCM/C6-Si LIBs coupled with comprehensive chemical/mechanical degradation mechanisms. The model includes chemical mechanisms at the C6-Si anode solid electrolyte interface (SEI), Li plating, and NCM cathode electrolyte interface (CEI), as well as mechanical mechanisms of loss of active material (LAM) for C6, Si, and NCM. Based on this model, we comprehensively investigate the effect of capacity loss by (dis)charge rates and ambient temperatures, obtaining the aging characteristics and the contribution of each mechanism to loss under different variables. Furthermore, we quantitatively analyze the sensitivity and response characteristics of the degradation sub-mechanism to (dis)charge rate and temperature. This study introduces an advanced aging analysis model for NCM/C6-Si LIBs, which can effectively decouple the operational characteristics of the degradation mechanism and provide guidance for developing next-generation high-energy LIBs.

Machine learning solutions for enhanced performance in plant-based microbial fuel cells

It is well known that numerous operational, material and design variables act upon the performance of a plant-based microbial fuel cell which is an emerging sustainable and versatile energy device like hydrogen fuel cells. However, due to the high complexity of these bioelectrochemical systems, new solutions are required to optimize performance and uncover hidden relationships between dominant fuel cell variables. For this purpose, a database of 229 observations was created for plant-based microbial fuel cells (PMFCs) with 159 descriptor variables and a target variable (maximum power density) based on experimental results from 51 recent publications. Then, some machine learning solutions like principal component analysis (PCA), classification trees and SHapley Additive exPlanations (SHAP) analysis were applied. The PCA indicated mainly two routes involving low and high chemical oxygen demand (COD) towards high maximum power density which consists of the plant family, wastewater type, support media, construction design, separator type, anode and cathode electrodes and light source. SHAP analysis revealed that the most important factors for high performance are operating temperature, natural light, soil support medium, and constructed wetland design. Finally, the classification tree successfully demonstrated nine routes towards high maximum power density which exclude the use of graphite plate cathode electrodes.

Longevity studies for the CMS Drift Tubes towards HL-LHC

The High Luminosity LHC (HL-LHC) program will pose a great challenge for the CMS Muon System. Existing subdetectors, which consist of Drift Tubes (DT), Resistive Plate Chambers (RPC) and Cathode Strip Chambers (CSC), will have to operate at 5 times larger instantaneous luminosity than the designed for, and, consequently, will have to sustain about 10 times the original LHC integrated luminosity. Longevity of DT system will be crucial to ensure a good performance in the CMS barrel region. Assessing DT performance is part of the upgrade program. In this talk will be reported the outcome of the accelerated irradiation studies, carried on at the CERN Gamma Irradiation Facility (GIF++) and recently concluded. These studies allowed to estimate performance of DT up to 3 times HL-LHC, and to plan a strategy to keep the longevity effects under control.

Analytical analysis of the generation of a rotating driving magnetic field on the outer surface of a magnetic pinch load with a helical return current post

A recently emerging approach adopts a directionally time-varying (rotating) magnetic field to drive a pinch load, aiming to mitigate the inherent magneto-Rayleigh-Taylor instability in dynamic Z pinches. A helical return current post (RCP) serves as a functional structural element capable of generating the requisite driving magnetic field for this purpose in the load region. This paper first calculates the current azimuthally induced on the outer surface of a magnetically pinched load within this type of RCP using a zero-dimensional lumped-parameter circuit model. The results show that the induced current deviates significantly from the presumed “perfect” induced current (100% amplitude) as reported in the literature [S. A. Sorokin, ); P. F. Schmit , ); G. A. Shipley , ); and P. C. Campbell , ], with an effective coefficient of current induction considerably less than 1. However, even when the load is fully compressed to the axis, the effective coefficient does not approach zero but rather converges to a finite value that solely depends on the aspect ratio of the RCP. This is quite favorable for the suppression of magneto-Rayleigh-Taylor instability in the Z pinch. As for the pointlike X pinch, the axial magnetic field does not tend to zero but a finite value, though the effective coefficient tends to zero, and this result may be used to suppress the instability in X pinch and improve the time stability and spatiotemporal unity of hot spots. In addition, the anode and cathode plates have the potential to enhance the current induced in the load. This paper then analyzes the axial distribution and time behavior of the induced current adopting an approximate analytical method and numerical integration and finds an approximate invariance that can be well characterized by δt, the product of the normalized skin depth and time. Similar values of δt indicate similar axial distribution characteristics. When δt is lower than, at, or higher than the critical region (∼0.1–0.3), the axial distribution appears dumbbell shaped, nearly flat, and arched, respectively. These distributively induced currents can be exploited to achieve quasispherical, near flat, and dumbbell-shaped implosions, respectively. Published by the American Physical Society 2024

High‐Performance Anion Exchange Membrane Fuel Cells Enabled by Nitrogen Configuration Optimization in Graphene‐Coated Nickel for Enhanced Hydrogen Oxidation

Anion exchange membrane fuel cell (AEMFC) technology is attracting intensive attention, due to its great potential by using non‐precious‐metal catalysts (NPMCs) in the cathode and cheap bipolar plate materials in alkaline media. However, in such case, the kinetics of hydrogen oxidation reaction (HOR) in the anode is two orders of magnitude sluggish than that of acidic electrolytes, which is recognized as the grand challenge in this field. Herein, we report the rationally designed Ni nanoparticles encapsulated by N‐doped graphene layers (Ni@NG) using a facile pyrolysis strategy. Based on the density functional theory calculations and electrochemical performance analysis, it is witnessed that the rich Pyridinic‐N within the graphene shell optimizes the binding energy of the intermediates, thus enabling the fundamentally enhanced activity for HOR with robust stability. As a proof of concept, the resultant Ni@NG sample as the anode with a low loading (1.8 mg cm−2) in AEMFCs delivers a high peak power density of 500 mW cm−2, outperforming all of those of NPMC‐based analogs ever reported.

Chemical-physical parameters and microbial community changes induced by electrodes polarization inhibit PCB dechlorination in a marine sediment

Microbial reductive dechlorination of organohalogenated pollutants is often limited by the scarcity of electron donors, that can be overcome with microbial electrochemical technologies (METs). In this study, polarized electrodes buried in marine sediment microcosms were investigated to stimulate PCB reductive dechlorination under potentiostatic (−0.7 V vs Ag/AgCl) and galvanostatic conditions (0.025 mA·cm−2-0.05 mA·cm−2), using graphite rod as cathode and iron plate as sacrificial anode. A single circuit and a novel two antiparallel circuits configuration (2AP) were investigated. Single circuit polarization impacted the sediment pH and redox potential (ORP) proportionally to the intensity of the electrical input and inhibited PCB reductive dechlorination. The effects on the sediment’s pH and ORP, along with the inhibition of PCB reductive dechlorination, were mitigated in the 2AP system. Electrodes polarization stimulated sulfate-reduction and promoted the enrichment of bacterial clades potentially involved in sulfate-reduction as well as in sulfur oxidation. This suggested the electrons provided were consumed by competitors of organohalide respiring bacteria and specifically sequestered by sulfur cycling, which may represent the main factor limiting the applicability of METs for stimulating PCB reductive dechlorination in marine sediments.

Magnetization roasting combined with multi-stage extraction for selective recovery of lithium from spent lithium-ion batteries

Lithium-ion batteries recycling is crucial for environmental protection and resource conservation. Among the battery components, lithium holds high value, but current recovery methods exhibit limited efficiency in selectively extracting lithium from spent electrode materials. In this study, we propose a novel pathway that combines magnetization roasting with multi-stage extraction to enhance the recovery of lithium from spent electrode materials. The process begins with the decomposition of the spent ternary cathode material into CoO, NiO, MnO, Co, and Ni at 600 ℃ for 30 min using pyrolysis product-derived reducing agents. Heat-induced magnetization of the cathode plates facilitates magnetic separation, effectively isolating cathode, and anode plates. The cathode material can be recycled by water impact crushing combined with sieving, and 40.80 % lithium dissolves into water for recycling. The comprehensive recycling efficiency of lithium is up to 95.30 % after carbothermal reduction with 15 % carbon addition. The sub-microlevel migration behavior of lithium ions in the proposed scheme was also examined for further mechanistic insights.

Novel strategy for cathode in iron-lead single-flow battery: Electrochemically modified porous graphite plate electrode

Porous electrodes play a pivotal role in shaping the electrochemical performance, cost, and the assembly complexity of redox flow batteries. In this paper, the effects of porous structure on the electrochemical performance of graphite electrodes are first studied. Subsequently, a low-cost, high-performance graphite plate cathode is developed for redox flow battery using controlled electrochemical corrosion as a facile and effective electrode modification method. As a result, the electrochemical performance of the porous graphite electrode is significantly enhanced, and a revolutionary design of the iron‑lead single-flow battery is implemented by substituting graphite felt cathode with the modified porous graphite plate electrode. The iron‑lead battery with modified flat graphite plate cathode demonstrates high energy efficiencies, ranging from 90.91 % to 77.13 % between 10 and 40 mA/cm2, comparable to those obtained with graphite felt cathode. By combining the anode, bipolar plate, and cathode into one piece of graphite plate, a novel stack design is achieved with significant thickness reduction of the unit cell from 9 mm to 3 mm, resulting in notably increased energy and power density, improved assembly efficiency and reduced components cost of stacks.

1D One-Phase Modeling of the Anode Catalyst Layer/Porous Transport Layer Interface Affecting Proton Exchange Membrane Water Electrolysis

Optimizing the structure of the porous transport layer (PTL) is crucial for improving the performance of proton exchange membrane water electrolysis (PEMWE), particularly for cells with low anode catalyst loadings. A growing number of studies reveal that catalysts are normally not entirely utilized in PEMWE, whereas the degree of catalyst utilization strongly depends on the structure of the PTL. As the oxygen evolution reaction (OER) at the anode is the limiting reaction step in PEMWE, inefficient use of the anode catalyst layer (aCL) would result in higher activation losses and, thus, cause a waste of unused catalysts [1–3]. This phenomenon becomes more serious when catalyst loading is reduced to meet the eco-friendly requirement of $2 per kgH2 while conserving noble material resources [4].Schuler et al. [1, 5] combined commercial CCMs with different PTL configurations, and found that with different aCL/PTL interface properties, the activation overpotential could have a maximum deviation of 20 mA at 0.1 A/cm2. Peng et al. [2] manufactured an ultra-low Ir loading CCM with 0.03 mgIr/cm2. Optimizing the aCL/PTL interface showed that the activation overpotential can have a maximum deviation of 40 mV at 0.75 A/cm2. Previous studies concluded that the aCL/PTL interface is crucial for improving the catalyst utilization. Consequently, the triple-phase boundary (TPB) site concept at the aCL/PTL interface is gaining more and more attention: the catalysts can only be entirely activated at reaction sites with sufficient water supply, ionic and electronic conductivities, and oxygen removal pathways [3]. According to TPB, not all reaction sites on the aCL meet these requirements. Figure 1 shows the corresponding physical picture. At the contact point of aCL and PTL (S) offers much greater electronic conductivity compared to the pore area (P), where electron removal is limited by the aCL in-plane conductivity (i.e., 1.85×106 S/m vs. 65.8 S/m) [3]. However, beneath the contact area (S), mass transport of oxygen is limited, indicating the necessity of optimizing the aCL/PTL interface.Figure 1: Illustration of physical picture at aCL/PTL interface.In our contribution, we implement a one-dimensional, one-phase model to investigate the interplay between PTL geometry at the aCL/PTL interface and catalyst utilization. The PTL transports water toward the aCL and electrons and oxygen toward the cathode and anode bipolar plates, respectively [6]. To simplify the physical conditions, we assume sufficient water supply and ion removal for the reaction sites on the aCL. Therefore, mass transport and electron transport limitations are only influenced by the aCL/PTL interface properties. Oxygen is assumed to dissolve in water only so that bubble formation does not disturb the reaction sites. Additionally, an ideal heat management condition is assumed in the model to achieve an isothermal condition. Our simulation results are in good agreement with literature, enabling the prediction of activation overpotentials corresponding to the PTL structure at aCL/PTL interface. Moreover, our results illustrate the local aCL behavior, which can be used to optimize the porous structure at the aCL/PTL interface, maximizing catalyst utilization. With our model, we aim to screen for an optimum PTL structure for a given aCL, allowing us to improve PEMWE cell performance by minimization of activation losses.

A Green and Fluorine‐Free Fabrication of 3D Self‐Supporting MXene by Combining Anodic Electrochemical In Situ Etching with Cathodic Electrophoretic Deposition for Electrocatalytic Hydrogen Evolution

AbstractThe work presents a green and fluorine‐free environmentally friendly two‐electrode system, which enables the direct fabrication of the corresponding 3D MXene electrodes by the synergistic combination of anodic electrochemical in situ Al etching from Mo2TiAlC2 MAX and cathodic electrophoretic deposition. In just several minutes, the Mo2TiC2 MXene can be deposited on the cathode plate (Pt foil or carbon cloth) without the need for organic large‐molecule intercalation agents or ultrasound treatment. This approach allows an efficient separation of MXene from the electrolyte, leading to a significant reduction in the quantity of waste acid generated by conventional acid etching processes. The electrochemically etched‐MXene can be uniformly and stably deposited onto carbon cloth (E‐MXene@CC), enabling its direct utilization as a 3D electrocatalyst for hydrogen evolution reaction (HER). This unique 3D E‐MXene@CC exhibits a moderate HER performance and outperforms most of the reported pure non‐precious MXene‐based catalysts in 0.5 m H2SO4. In order to clarify the catalytic mechanism, in situ Raman spectroscopy of 3D E‐MXene@CC reveals a significant down‐shift without observing any new bands when the HER potential shifts negatively, which can be attributed to H+ intercalation.

Performance of Solar-based Electrochemical System as Post-treatment of Hospital Wastewater Contaminated with Ciprofloxacin

T his research evaluated performance of a solar-based electrochemical system as a post-treatment of hospital wastewater contaminated with Ciprofloxacin (CIP), an antibiotic drug. Two laboratory-scale electrochemical units, and consisting of 2-5 anode and 1-4 cathode plates, were employed. Two types of electrode plates, aluminum (Al) and stainless steel (Ss), were installed in the units and their treatment efficiencies were investigated. Optimum conditions of the electrochemical system were determined by using a synthetic wastewater containing 0.01-20 mg/L of CIP (batch system); these experimental results were validated by using an actual hospital wastewater and a solar-based electrochemical system (continuous system). The experimental results of the batch system showed that the maximum CIP removal of 69% could be achieved at 10 minutes of hydraulic retention time (HRT), 18 volts in a voltage of power source (VPS), 83 A/m2 of current density (CD), and 1 cm of inter-electrode distance (IED) on Al plates. Similar results in the continuous system were obtained when the electrochemical system was fed with hospital wastewater containing CIP of about 350 ng/L. Application of solar-based energy in the electrochemical system showed similar efficiency of CIP removal, suggesting the applicability of the clean energy system for post-treatment of hospital wastewater containing antibiotic drugs

Enhancement of hydrogen production via optimizing micro-structures of electrolyzer on a microfluidic platform

Electrochemical water splitting plays a vital role for production of hydrogen (H2). Enhancing the rate of hydrogen separation from the electrode is crucial for improving the performance of water electrolyzers. The water electrolyzers often encounter issues such as air bubble adhesion to the electrode plate, leading to increased electrical resistance, reduced current density, and thus lower hydrogen generation rates. In addition, the compact configuration of electrolyzer and non-transparent electrode plates make it impracticable to observe and analyze the gas-liquid two-phase flow between the anode and cathode plates. Hence, a methodology is in high demand to experimentally investigate the two-phase flow within the electrolyzer, which could be further used to guide the design and optimization of the electrolyzer. In this work, we propose to utilize a microfluidic system as a phantom of electrolyzer. The transparent material of the microfluidic chip allows optical inspection and measurement of the two-phase flow. Specifically, we propose to optimize the two-phase flow by manipulating the micro-structure of the flow, which has been theoretically and experimentally demonstrated to effectively remove the gas bubbles attached to the wall and consequently enhance the hydrogen production rate. The dimensions of the proposed micro-structures can be potentially extended and applied to industrial electrolyzers according to the principle of similarity.