Production & Supply Chain
Hydrogen Production from H2S-steam Reforming using Recycled Sour Water: Insights from Thermodynamic and Kinetic Modeling
Sep 2025
Publication
Given the rising interest in hydrogen economy alternative feedstocks are explored for their potential use for hydrogen production such as H2S a notable byproduct from oil and gas operations. This study presents a computational investigation on the thermodynamics kinetics and mechanisms of non-catalytic H2S-steam reforming (H2SSR) as a pathway for H2S-to-H2 benchmarked to H2S thermal decomposition (H2SPyrol) (as a limiting case without water). The mechanism integrates key elementary steps form different reaction pathways including H2S partial oxidation H2O reduction and H2S thermal decomposition. Results from the model are validated using available experimental data for H2SPyrol and H2SSR. Homogeneous gas-phase reactions are modelled at different H2O:H2S ratios reaction temperatures pressure and times. Thermodynamically the H2SSR reaction is unfavorable due to the presence of water and its role in increasing the reaction complexity and endothermicity; however kinetically water contributes to increasing the hydrogen yield at least 9 times that from H2SPyrol achieving 99.23 % H2S conversion at 1473 K with an excess H2O:H2S feed ratio of 200:1. The contribution of water during the H2SSR reaction is interpreted using reaction path and rate of production analyses demonstrating its role in producing an abundant pool of OH and H radicals. These radicals catalyze the cleavage of H2S-SH bonds accelerating hydrogen production at an optimal reaction time of 0.07–0.105 s. This study paves the path for future kinetic and catalytic research to optimize the technical viability of H2SSR as a promising H2S-to-H2 conversion pathway for sour wastewater reutilization.
Optimising Green Hydrogen Production across Europe: How Renewable Energy Sources Shape Plant Design and Costs
Sep 2025
Publication
Green hydrogen is widely recognised as a key enabler for decarbonising heavy industry and long-haul transport. However producing it cost-competitively from variable renewable energy sources presents design challenges. In this study a mixed-integer linear programming (MILP) optimisation framework is developed to minimise the levelised cost of hydrogen (LCOH) from renewable-powered electrolysers. The analysis covers all European countries and explores how wind and solar resource availability influences the optimal sizing of renewable generators electrolysers hydrogen storage and batteries under both current and future scenarios. Results show that renewable resource quality strongly affects system design and hydrogen costs. At present solar-only systems yield LCOH values of 7.4–24.7 €/kg whereas wind-only systems achieve lower costs (5.1–17.1 €/kg) due to higher capacity factors and reduced storage requirements. Hybrid systems combining solar and wind emerge as the most cost-effective solution reducing average LCOH by 57 % compared to solar-only systems and 25 % compared to wind-only systems effectively narrowing geographical cost disparities. In the future scenario LCOH declines to 3–4 €/kg confirming renewable hydrogen’s potential to become economically competitive throughout Europe. A key contribution of this work is the derivation of design guidelines by correlating renewable resource quality with technical energy and economic indicators.
A Cation-exchange Membrane Direct Formate-CO2 Fuel Cell: Enabling Simultaneous Hydrogen Production and CO2 Utilization
Sep 2025
Publication
The carbon-neutral and carbon-negative energy utilization technologies have long been people pursued to realize the strategic objective of carbon neutrality. Herein we propose a cation-exchange membrane (CEM) direct formate-CO2 fuel cell that possesses the capability of simultaneously generating electricity and producing hydrogen as well as continuously transforming carbon dioxide into pure sodium bicarbonate. Using the CO2- derived formate fuel the roof-of-concept CEM direct formate-CO2 fuel cell exhibits a peak power density of 38 mW cm− 2 at 80 ◦C without the assistance of additional electrolyte. The fairly stable constant-current discharge curve along with the detected hydrogen and pure sodium bicarbonate prove the conceptual feasibility of this electricity‑hydrogen-bicarbonate co-production device. By adding alkaline electrolyte to the anode we achieved a higher peak power density of 63 mW cm− 2 at the corresponding hydrogen production rate of 0.57 mL min− 1 cm− 2 . More interestingly the concentrations of pure NaHCO3 solution can be controlled by adjusting the cathode water flow rate and fuel cell discharge current density. This work presents a theoretically feasible avenue for coupling hydrogen production and CO2 utilization.
Predicting Hydrogen Production from Formic Acid Dehydrogenation Using Smart Connectionist Models
Feb 2025
Publication
Hydrogen is a promising clean energy source that can be a promising alternative to fossil fuels without toxic emissions. It can be generated from formic acid (FA) through an FA dehydrogenation reaction using an active catalyst. Activated carbon-supported palladium (Pd/C) catalyst has superior activity properties for FA dehydrogenation and can be reused after deactivation. This study focuses on predicting the FA conversion to H2 (%) in the presence of Pd/C using machine learning techniques and experimental data (1544 data points). Six different machine learning algorithms are employed including random forest (RF) extremely randomized trees (ET) decision tree (DT) K nearest neighbors (KNN) support vector machine (SVM) and linear regression (LR). Temperature time FA concentration catalyst size catalyst weight sodium formate (SF) concentration and solution volume are considered as the input data while the FA conversion to H2 (%) is the target value. Based on the train and test outcomes the ET is the most accurate model for the prediction of FA conversion to H2 (%) and its accuracy is assessed by root mean squared error (RMSE) R-squared (R2 ) and mean absolute error (MAE) which are 3.16 0.97 and 0.75 respectively. In addition the results reveal that solution volume is the most significant feature in the model development process that affects the amount of FA conversion to H2 (%). These techniques can be used to assess the efficiency of other catalysts in terms of type size weight percentage and their effects on the amount of FA conversion to H2 (%). Moreover the results of this study can be used to optimize the energy cost and environmental aspects of the FA dehydrogenation process.
Performance and Durability of a 50-kW Proton Exchange Membrane Water Electrolyzer using Various Fluctuating Power Sources
Sep 2025
Publication
Scaling up water electrolyzers for green hydrogen production poses challenges in predicting megawatt-to gigawatt (MW/GW)-class system behavior under renewable energy power fluctuations. A fundamental evaluation is warranted to connect the characteristics of W- to kW-class laboratory electrolyzers with those of MW- to GW-class systems in practical applications. This study evaluates a 50 kW-class proton exchange membrane water electrolyzer with 30 cells using an accelerated degradation test protocol a simulated renewable energy power and a constant current of 800 A (1.33 A cm− 2 ) and the results show average degradation rates per cell of 40.4 27.2 and 5.6 μV h− 1 respectively. Evidently a voltage as approximate indicator exists for each cell to effectively suppress degradation. Durability tests reveal reductions in anode catalyst loading on the membrane electrode assemblies and inhomogeneous oxidation of the anode current collector. The findings contribute to predicting the stacking performance of electrolyzers for practical applications.
Theoretical Thermal Management Concepts of Recovery Heat Waste in Solid Oxide Fuel Cell System
Oct 2025
Publication
Solid oxide electrolysis cells (SOEC) system has potential to offer an efficient green hydrogen production technology. However the significant cost of this technology is related to the high operating temperatures materials and thermal management including the waste heat. Recovering the waste heat can be conducted through techniques to reduce the overall energy consumption. This approach aims to improve accuracy and efficiency by recovering and reusing the heat that would otherwise be lost. In this paper thermal energy models are proposed based on waste heat recovery methodologies to utilize the heat from outlet fluids within the SOEC system. The mathematical methods for calculating thermal energy and energy transfer in SOEC systems have involved the principles of heat transfer. To address this different simplified thermal models are developed in Simulink Matlab R2025b. The obtained results for estimating proper thermal energy for heating incoming fluids and recycled heat are discussed and compared to determine the efficient and potential thermal model for improvement the waste heat recovery.
Towards Carbon-Neutral Hydrogen: Integrating Methane Pyrolysis with Geothermal Energy
Oct 2025
Publication
Methane pyrolysis produces hydrogen (H2) with solid carbon black as a co-product eliminating direct CO2 emissions and enabling a low-carbon supply when combined with renewable or low-carbon heat sources. In this study we propose a hybrid geothermal pyrolysis configuration in which an enhanced geothermal system (EGS) provides baseload preheating and isothermal holding while either electrical or solar–thermal input supplies the final temperature rise to the catalytic set-point. The work addresses four main objectives: (i) integrating field-scale geothermal operating envelopes to define heatintegration targets and duty splits; (ii) assessing scalability through high-pressure reactor design thermal management and carbon separation strategies that preserve co-product value; (iii) developing a techno-economic analysis (TEA) framework that lists CAPEX and OPEX incorporates carbon pricing and credits and evaluates dual-product economics for hydrogen and carbon black; and (iv) reorganizing state-of-the-art advances chronologically linking molten media demonstrations catalyst development and integration studies. The process synthesis shows that allocating geothermal heat to the largest heat-capacity streams (feed recycle and melt/salt hold) reduces electric top-up demand and stabilizes reactor operation thereby mitigating coking sintering and broad particle size distributions. Highpressure operation improves the hydrogen yield and equipment compactness but it also requires corrosion-resistant materials and careful thermal-stress management. The TEA indicates that the levelized cost of hydrogen is primarily influenced by two factors: (a) electric duty and the carbon intensity of power and (b) the achievable price and specifications of the carbon co-product. Secondary drivers include the methane price geothermal capacity factor and overall conversion and selectivity. Overall geothermal-assisted methane pyrolysis emerges as a practical pathway to turquoise hydrogen if the carbon quality is maintained and heat integration is optimized. The study offers design principles and reporting guidelines intended to accelerate pilot-scale deployment.
Global Research Trends in Catalysis for Green Hydrogen Production from Wastewater: A Bibliometric Study (2010–2024)
Sep 2025
Publication
By turning a waste stream into a clean energy source green hydrogen generation from wastewater provides a dual solution to energy and environmental problems. This study presents a thorough bibliometric analysis of research trends in the field of green hydrogen generation from wastewater between 2010 and 2024. A total of 221 publications were extracted from Scopus database and VOSviewer (1.6.20) was used as a visualization tool to identify influential authors institutions collaborations and thematic focus areas. The analysis revealed a significant increase in research output with a peak of 122 publications in 2024 with a total of 705 citations. China had the most contributions with 60 publications followed by India (30) and South Korea (26) indicating substantial regional involvement in Asia. Keyword co-occurrence and coauthorship network mapping revealed 779 distinct keywords grouped around key themes like electrolysis hydrogen evolution reactions and wastewater treatment. Significantly this work was supported by contributions from 115 publication venues with the International Journal of Hydrogen Energy emerging as the most active and cited source (40 articles 539 citations). The multidisciplinary aspect of the area was highlighted by keyword co-occurrence analysis which identified recurring themes including electrolysis wastewater treatment and hydrogen evolution processes. Interestingly the most-cited study garnered 131 citations and discussed the availability of unconventional water sources for electrolysis. Although there is growing interest in the field it is still in its initial phases indicating a need for additional research particularly in developing countries. This work offers a basic overview for researchers and policymakers who are focused on promoting the sustainable generation of green hydrogen from wastewater.
Engineering Photocatalytic Membrane Reactors for Sustainable Energy and Environmental Applications
Oct 2025
Publication
Photocatalytic membrane reactors (PMRs) which combine photocatalysis with membrane separation represent a pivotal technology for sustainable water treatment and resource recovery. Although extensive research has documented various configurations of photocatalytic-membrane hybrid processes and their potential in water treatment applications a comprehensive analysis of the interrelationships among reactor architectures intrinsic physicochemical mechanisms and overall process efficiency remains inadequately explored. This knowledge gap hinders the rational design of highly efficient and stable reactor systems—a shortcoming that this review seeks to remedy. Here we critically examine the connections between reactor configurations design principles and cutting-edge applications to outline future research directions. We analyze the evolution of reactor architectures relevantreaction kinetics and key operational parameters that inform rational design linking these fundamentals to recent advances in solar-driven hydrogen production CO2 conversion and industrial scaling. Our analysis reveals a significant disconnect between the mechanistic understanding of reactor operation and the system-level performance required for innovative applications. This gap between theory and practice is particularly evident in efforts to translate laboratory success into robust and economically feasible industrial-scale operations. We believe that PMRs willrealize theirtransformative potential in sustainable energy and environmental applications in future.
High-Efficiency, Lightweight, and Reliable Integrated Structures—The Future of Fuel Cells and Electrolyzers
Oct 2025
Publication
The high efficiency light weight and reliability of hydrogen energy electrochemical equipment are among the future development directions. Membrane electrode assemblies (MEAs) and electrolyzers as key components have structures and strengths that determine the efficiency of their power generation and the hydrogen production efficiency of electrolyzers. This article summarizes the evolution of membrane electrode and electrolyzer structures and their power and efficiency in recent years highlighting the significant role of integrated structures in promoting proton transport and enhancing performance. Finally it proposes the development direction of integrating electrolyte and electrode manufacturing using phase-change methods.
Investigation of Hydrogen Production System-Based PEM EL: PEM EL Modeling, DC/DC Power Converter, and Controller Design Approaches
Apr 2023
Publication
The main component of the hydrogen production system is the electrolyzer (EL) which is used to convert electrical energy and water into hydrogen and oxygen. The power converter supplies the EL and the controller is used to ensure the global stability and safety of the overall system. This review aims to investigate and analyze each one of these components: Proton Exchange Membrane Electrolyzer (PEM EL) electrical modeling DC/DC power converters and control approaches. To achieve this desired result a review of the literature survey and an investigation of the PEM EL electrical modeling of the empirical and semi-empirical including the static and dynamic models are carried out. In addition other sub-models used to predict the temperature gas flow rates (H2 and O2 ) hydrogen pressure and energy efficiency for PEM EL are covered. DC/DC power converters suitable for PEM EL are discussed in terms of efficiency current ripple voltage ratio and their ability to operate in the case of power switch failure. This review involves analysis and investigation of PEM EL control strategies and approaches previously used to achieve control objectives robustness and reliability in studying the DC/DC converter-PEM electrolyzer system. The paper also highlights the online parameter identification of the PEM electrolyzer model and adaptive control issues. Finally a discussion of the results is developed to emphasize the strengths weaknesses and imperfections of the literature on this subject as well as proposing ideas and challenges for future work.
Open-Circuit Switch Fault Diagnosis and Accommodation of a Three-Level Interleaved Buck Converter for Electrolyzer Applications
Mar 2023
Publication
This article proposes a novel open-circuit switch fault diagnosis method (FDM) for a three-level interleaved buck converter (TLIBC) in a hydrogen production system based on the water electrolysis process. The control algorithm is suitably modified to ensure the same hydrogen production despite the fault. The TLIBC enables the interfacing of the power source (i.e. low-carbon energy sources) and electrolyzer while driving the hydrogen production of the system in terms of current or voltage. On one hand the TLIBC can guarantee a continuity of operation in case of power switch failures because of its interleaved architecture. On the other hand the appearance of a power switch failure may lead to a loss of performance. Therefore it is crucial to accurately locate the failure in the TLIBC and implement a fault-tolerant control strategy for performance purposes. The proposed FDM relies on the comparison of the shape of the input current and the pulse width modulation (PWM) gate signal of each power switch. Finally an experimental test bench of the hydrogen production system is designed and realized to evaluate the performance of the developed FDM and fault-tolerant control strategy for TLIBC during post-fault operation. It is implemented with a real-time control based on a MicroLabBox dSPACE (dSPACE Paderborn Germany) platform combined with a TI C2000 microcontroller. The obtained simulation and experimental results demonstrate that the proposed FDM can detect open-circuit switch failures in one switching period and reconfigure the control law accordingly to ensure the same current is delivered before the failure.
Impact of Solar Thermal Energy and Calcium Looping Implementation on Biomass Gasification for Low-carbon Hydrogen Production
Sep 2025
Publication
In the search of low-carbon hydrogen production routes this study evaluates four biomass gasification processes: conventional steam gasification (CSG) sorption-enhanced gasification (SEG) and their solar-assisted variants (SSG and SSEG). The comparison focuses on three key aspects: hydrogen production overall energy efficiency (to H2 and power) and carbon capture potential (generation of a pure CO2 process stream for storage or utilization). For a realistic comparison a pseudo-equilibrium model of a double-bed gasifier was developed based on experimental correlations of char conversion under conventional and SEG conditions. The solar processes were designed for stable year-round operation considering seasonal weather variations by appropriately dimensioning the heliostat field and the thermal and chemical energy storage systems whose inventory dynamics were modelled. Both the gasifier and central solar tower models were rigorously validated with published data enhancing the reliability of the results. Solar-assisted configurations significantly outperform non-solar ones in hydrogen production with SSEG yielding 128 kg H2/ton biomassdaf compared to 90–95 kg for non-solar options. SEG demonstrates superior carbon capture potential (76 %) while solar-assisted systems achieve higher energy efficiency (67–73 % vs. 60–63 % for non-solar). These results underscore the potential of solar-assisted gasification for sustainable hydrogen production offering enhanced yields improved efficiency and substantial carbon capture capabilities. Future work will involve economic and environmental analysis to determine the best overall configuration.
Silicon Nanostructures for Hydrogen Generation and Storage
Oct 2025
Publication
Today hydrogen is already widely regarded as up-and-coming source of energy. It is essential to meet energy needs while reducing environmental pollution since it has a high energy capacity and does not emit carbon oxide when burned. However for the widespread application of hydrogen energy it is necessary to search new technical solutions for both its production and storage. A promising effective and cost-efficient method of hydrogen generation and storage can be the use of solid materials including nanomaterials in which chemical or physical adsorption of hydrogen occurs. Focusing on the recommendations of the DOE the search is underway for materials with high gravimetric capacity more than 6.5% wt% and in which sorption and release of hydrogen occurs at temperatures from −20 to +100 ◦C and normal pressure. This review aims to summarize research on hydrogen generation and storage using silicon nanostructures and silicon composites. Hydrogen generation has been observed in Si nanoparticles porous Si and Si nanowires. Regardless of their size and surface chemistry the silicon nanocrystals interact with water/alcohol solutions resulting in their complete oxidation the hydrolysis of water and the generation of hydrogen. In addition porous Si nanostructures exhibit a large internal specific surface area covered by SiHx bonds. A key advantage of porous Si nanostructures is their ability to release molecular hydrogen through the thermal decomposition of SiHx groups or in interaction with water/alkali. The review also covers simulations and theoretical modeling of H2 generation and storage in silicon nanostructures. Using hydrogen with fuel cells could replace Li-ion batteries in drones and mobile gadgets as more efficient. Finally some recent applications including the potential use of Si-based agents as hydrogen sources to address issues associated with new approaches for antioxidative therapy. Hydrogen acts as a powerful antioxidant specifically targeting harmful ROS such as hydroxyl radicals. Antioxidant therapy using hydrogen (often termed hydrogen medicine) has shown promise in alleviating the pathology of various diseases including brain ischemia–reperfusion injury Parkinson’s disease and hepatitis.
What is Next in Anion-Exchange Membrane Water Electrolyzers? Bottlenecks, Benefits, and Future
Mar 2022
Publication
As highlighted by the recent roadmaps from the European Union and the United States water electrolysis is the most valuable high-intensity technology for producing green hydrogen. Currently two commercial low-temperature water electrolyzer technologies exist: alkaline water electrolyzer (A-WE) and proton-exchange membrane water electrolyzer (PEM-WE). However both have major drawbacks. A-WE shows low productivity and efficiency while PEM-WE uses a significant amount of critical raw materials. Lately the use of anion-exchange membrane water electrolyzers (AEM-WE) has been proposed to overcome the limitations of the current commercial systems. AEM-WE could become the cornerstone to achieve an intense safe and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here the status of AEM-WE development is discussed with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM-WE research indicating the targets to be achieved.
Hydrogen Production Plant via an Intensified Plasma-based Technology
Oct 2025
Publication
Developing cleaner processes via newer technologies will accelerate advancement toward more sustainable energy systems. Hydrogen is an energy carrier and an intermediate molecule in chemical processes. This research investigates an innovative hydrogen production process utilizing a non-thermal Cold Atmospheric Pressure Plasma-based Reformer (CAPR). Exploring environmentally friendly and economically viable pathways for hydrogen production is crucial for addressing climate change and reducing the carbon footprint of industrial processes. The study investigates the conversion of natural gas to hydrogen at ambient temperature and pressure highlighting the ability of plasma-based technology to operate without direct CO2 emissions.<br/>Initially through experimental studies natural gas was passed through the CAPR where the plasma's energetic discharges initiate the reforming process. Subsequently the produced hydrogen along with other light hydrocarbons enters the separation system for producing purified hydrogen. The research focuses on techno-economic analyses and sensitivity assessments to determine the levelized cost of producing hydrogen via a nanosecond plasma-based refining plant and benchmark technologies. Sensitivity analyses identify two primary factors that significantly affect the levelized cost of hydrogen production in a plasma-based reforming system.<br/>The research suggests that instead of producing carbon dioxide and capturing the emitted CO2 utilize processes that do not emit direct CO2. CAPR shows potential for cost competitiveness with conventional hydrogen production methods including steam methane reforming (SMR) and electrolysis. The findings underscore the need for further research to optimize the system's performance and cost-effectiveness positioning CAPR as a potentially transformative technology for the chemical process industry.
Multi-Physics Coupling Simulation of H2O–CO2 Co-Electrolysis Using Flat Tubular Solid Oxide Electrolysis Cells
Oct 2025
Publication
Solid oxide electrolysis cells (SOECs) have emerged as a promising technology for efficient energy storage and CO2 utilization via H2O–CO2 co-electrolysis. While most previous studies focused on planar or tubular configurations this work investigated a novel flat tubular SOEC design using a comprehensive 3D multi-physics model developed in COMSOL Multiphysics 5.6. This model integrates charge transfer gas flow heat transfer chemical/electrochemical reactions and structural mechanics to analyze operational behavior and thermo-mechanical stress under different voltages and pressures. Simulation results indicate that increasing operating voltage leads to significant temperature and current density inhomogeneity. Furthermore elevated pressure improves electrochemical performance possibly due to increased reactant concentrations and reduced mass transfer limitations; however it also increases temperature gradients and the maximum first principal stress. These findings underscore that the design and optimization of flat tubular SOECs in H2O–CO2 co-electrolysis should take the trade-off between performance and durability into consideration.
Sustainable Hydrogen Production from Waste Plastics via Staged Chemical Looping Gasification with Iron-based Oxygen Carrier
Aug 2025
Publication
Thermo-chemical conversion of waste plastics offers a sustainable strategy for integrated waste management and clean energy generation. To address the challenges of low gas yield and rapid catalyst deactivation due to coking in conventional gasification processes an innovative three-stage chemical looping gasification (CLG) system specifically designed for enhanced hydrogen-rich syngas production was proposed in this work. A comparative analysis between conventional gasification and the staged CLG system were firstly conducted coupled with online gas analysis for mechanistic elucidation. The influence of Fe/Al molar ratios in oxygen carriers and their cyclic stability were systematically examined through multicycle experiments. Results showed that the three-stage CLG in the presence of Fe1Al2 demonstrated exceptional performance achieving 95.23 mmol/gplastic of H2 and 129.89 mmol/gplastic of syngas respectively representing 1.32-fold enhancement over conventional method. And the increased H2/CO ratio (2.68-2.75) reflected better syngas quality via water-gas shift. Remarkably the oxygen carrier maintained nearly 100% of its initial activity after 7 redox cycles attributed to the incorporation of Al2O3 effectively mitigating sintering and phase segregation through metal-support interactions. These findings establish a three-stage CLG configuration with Fe-Al oxygen carriers as an efficient platform for efficient hydrogen production from waste plastics contributing to sustainable waste valorisation and carbon-neutral energy systems.
A Review on the Use of Catalysis for Biogas Steam Reforming
Nov 2023
Publication
Hydrogen production from natural gas or biogas at different purity levels has emerged as an important technology with continuous development and improvement in order to stand for sustainable and clean energy. Regarding biogas which can be obtained from multiple sources hydrogen production through the steam reforming of methane is one of the most important methods for its energy use. In that sense the role of catalysts to make the process more efficient is crucial normally contributing to a higher hydrogen yield under milder reaction conditions in the final product. The aim of this review is to cover the main points related to these catalysts as every aspect counts and has an influence on the use of these catalysts during this specific process (from the feedstocks used for biogas production or the biodigestion process to the purification of the hydrogen produced). Thus a thorough review of hydrogen production through biogas steam reforming was carried out with a special emphasis on the influence of different variables on its catalytic performance. Also the most common catalysts used in this process as well as the main deactivation mechanisms and their possible solutions are included supported by the most recent studies about these subjects.
Integrated Membrane Distillation-solid Electrolyte-based Alkaline Water Electrolysis for Enhancing Green Hydrogen Production
Jan 2025
Publication
This paper investigates the circularity of green hydrogen and resource recovery from brine using an integrated approach based on alkaline water electrolysis (AWE). Traditional AWE employs highly alkaline electrolytes which can lead to electrode corrosion undesirable side reactions and gas cross-over issues. Conversely indirect brine electrolysis requires pre-treatment steps which negatively impact both techno-economics and environmental sustainability. In response this study proposes an innovative brine electrolysis process utilizing solid electrolytes (SELs). The process includes an on-site brine treatment facility leveraging a self-driven phase transition technique and incorporates a hydrophobic membrane as part of a membrane distillation (MD) system to facilitate the gas pathway. Polyvinyl alcohol (PVA) and tetraethylammonium hydroxide (TEAOH)-based electrolytes combined with potassium hydroxide (KOH) at various concentrations function as a self-wetted electrolyte (SWE). This design partially disperses water vapor while effectively preventing the intrusion of contaminated ions into the SWE and electrode-catalyst interfaces. PVA-TEAOH-KOH-30 wt% SWE demonstrated the highest ion conductivity (112.4 mScm−1) and excellent performance with a current density of 375 mAcm−2. Long-term electrolysis confirmed with a nine-fold brine in volume concentration factor (VCF) demonstrated stable performance without MD membrane wetting. The Cl−/ClO− and Br− concentrations in the SWE were reduced by five orders of magnitude compared to the original brine. This electrolyzer supports the circular use of resources with hydrogen as an energy carrier and concentrated brine and oxygen as valuable by-products aligning with the sustainable development goals (SDGs) and net-zero emissions by 2050.
No more items...