Sustainable Hydrogen Production Research Articles

Oxygen vacancy-rich CoMoO4/Carbon nitride S-scheme heterojunction for boosted photocatalytic H2 production: Microstructure regulation and charge transfer mechanism

Developing highly efficient S-scheme photocatalysts is a subject of immense interest for harnessing solar energy towards sustainable hydrogen production. Herein, a novel S-scheme heterojunction of oxygen vacancy-rich CoMoO4/CN (CMO/CN) photocatalyst was rationally constructed through loading CoMoO4 nanorods on carbon nitride (CN) nanosheets via a direct one-pot calcination method. The CMO/CN S-scheme heterojunction exhibited enhanced surface area, fine CN dispersion, rich oxygen vacancies, and accelerated charge separation/transfer efficiency, which were conducive to improving photocatalytic H2 evolution performance. Of note, the optimal 3 %CMO/CN sample displayed the highest H2 production rate of 8.35 mmol g−1 h−1, which is 4.6 folds that of pristine CN. In situ irradiated X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) characterizations confirmed the S-scheme charge transfer path between CN and CMO, which greatly promoted spatial charge separation. Density functional theory (DFT) calculations together with contact angle tests revealed the reduced activation energies for H2O dissociation and enhanced hydrophilicity of the CMO/CN. The CMO/CN photocatalysts also presented high stability and fine reusability. This work may provide insights into the combination of defect engineering and heterojunction designing for high-efficiency solar-to-chemical energy conversion.

Bipolar Membrane Seawater Splitting for Hydrogen Production: A Review.

The growing demand for clean energy has spurred the quest for sustainable alternatives to fossil fuels. Hydrogen has emerged as a promising candidate with its exceptional heating value and zero emissions upon combustion. However, conventional hydrogen production methods contribute to CO2 emissions, necessitating environmentally friendly alternatives. With its vast potential, seawater has garnered attention as a valuable resource for hydrogen production, especially in arid coastal regions with surplus renewable energy. Direct seawater electrolysis presents a viable option, although it faces challenges such as corrosion, competing reactions, and the presence of various impurities. To enhance the seawater electrolysis efficiency and overcome these challenges, researchers have turned to bipolar membranes (BPMs). These membranes create two distinct pH environments and selectively facilitate water dissociation by allowing the passage of protons and hydroxide ions, while acting as a barrier to cations and anions. Moreover, the presence of catalysts at the BPM junction or interface can further accelerate water dissociation. Alongside the thermodynamic potential, the efficiency of the system is significantly influenced by the water dissociation potential of BPMs. By exploiting these unique properties, BPMs offer a promising solution to improve the overall efficiency of seawater electrolysis processes. This paper reviews BPM electrolysis, including the water dissociation mechanism, recent advancements in BPM synthesis, and the challenges encountered in seawater electrolysis. Furthermore, it explores promising strategies to optimize the water dissociation reaction in BPMs, paving the way for sustainable hydrogen production from seawater.

Bifunctional Electrocatalysts for Overall and Hybrid Water Splitting.

Electrocatalytic water splitting driven by renewable electricity has been recognized as a promising approach for green hydrogen production. Different from conventional strategies in developing electrocatalysts for the two half-reactions of water splitting (e.g., the hydrogen and oxygen evolution reactions, HER and OER) separately, there has been a growing interest in designing and developing bifunctional electrocatalysts, which are able to catalyze both the HER and OER. In addition, considering the high overpotentials required for OER while limited value of the produced oxygen, there is another rapidly growing interest in exploring alternative oxidation reactions to replace OER for hybrid water splitting toward energy-efficient hydrogen generation. This Review begins with an introduction on the fundamental aspects of water splitting, followed by a thorough discussion on various physicochemical characterization techniques that are frequently employed in probing the active sites, with an emphasis on the reconstruction of bifunctional electrocatalysts during redox electrolysis. The design, synthesis, and performance of diverse bifunctional electrocatalysts based on noble metals, nonprecious metals, and metal-free nanocarbons, for overall water splitting in acidic and alkaline electrolytes, are thoroughly summarized and compared. Next, their application toward hybrid water splitting is also presented, wherein the alternative anodic reactions include sacrificing agents oxidation, pollutants oxidative degradation, and organics oxidative upgrading. Finally, a concise statement on the current challenges and future opportunities of bifunctional electrocatalysts for both overall and hybrid water splitting is presented in the hope of guiding future endeavors in the quest for energy-efficient and sustainable green hydrogen production.

Synthesis of MFe2O4 (M=Ni, Co) Nanoparticles by a Bicontinuous Microemulsion Method for the Oxygen Evolution Reaction

AbstractDeveloping efficient and low‐cost electrocatalysts for the oxygen evolution reaction (OER) is crucial for sustainable hydrogen production through water splitting. In this study, CoFe2O4 and NiFe2O4 nanoparticles as electrocatalysts were prepared via an inexpensive method involving the use of bicontinuous microemulsions as nanoreactors. The crystalline structure, morphology, and elemental composition of the electrocatalysts were characterized by XRD, Raman spectroscopy, TEM, and EDS elemental mapping. The electronic structure and textural properties were examined using XPS and the nitrogen adsorption‐desorption method. The OER measurements were carried out in a standard three‐electrode system. CoFe2O4 demonstrated relatively higher OER catalytic activity than NiFe2O4 in 1 M KOH solution, with a smaller overpotential of 410 mV to achieve a current density of 10 mA cm−2 and a smaller Tafel slope of 80 mV dec−1. In contrast, NiFe2O4 offered a higher overpotential of 450 mV to reach the same current density. The superior performance of CoFe2O4 is ascribed to higher ECSA, better conductivity, and lower charge transfer resistance. However, both electrocatalysts showed stability up to more than three hours of continuous performance.

Sustainable hydrogen production through water splitting: a comprehensive review

Sustainable hydrogen production through water splitting: a comprehensive review

Synergistic heterointerface engineering of Co9S8/Ni(OH)2 hierarchical nanosheets for remarkable overall water splitting

Sustainable production of hydrogen from electrochemical water spitting by cost-effective and non-precious bifunctional electrocatalyst is of remarkable interest and extremely desirable. Here, a novel hierarchical Co9S8/Ni(OH)2 heterostructure with porous nanosheets was fabricated as the heterogeneous bifunctional electrodes to achieve remarkable water electrolysis. Synergistic coexistence of Co9S8 and Ni(OH)2 nanostructure with crystalline-amorphous feature can induce a large number of chemically coupled heterointerfaces as catalytically accessible active sites to accelerate electron transfer kinetics and enable a super-hydrophilic feature to contact electrolyte and release gas bubbles. Thus, such Co9S8/Ni(OH)2 heterostructure electrode verifies a remarkable electrocatalytic activity with low overpotentials of 274 mV at 100 mA cm−2 for OER and 109 mV at 10 mA cm−2 for HER. As assembled in a lab-made electrolyzer, the Co9S8/Ni(OH)2 heterostructures as bifunctional electrodes enable 1.51 V to achieve an overall water splitting at 10 mA cm−2, along with the outstanding stability at about 100 mA cm−2 up to 55 h. This work paves a bright way to design and construct non-precious materials as effective and advanced electrocatalysts for electrolysis in water.

Construction of novel Ru-embedded bulk g-C3N4 photocatalysts toward efficient and sustainable photocatalytic hydrogen production

Novel Ru-embedded bulk graphitic carbon nitride (g-C3N4) photocatalysts containing different wt% of Ru (0.5–2 % wt) were synthesized by a simple mixing method of ruthenium complex with g-C3N4. The photocatalytic activity of the synthesized photocatalysts was assessed for hydrogen production in an aqueous solution containing methanol with and without Pt. The optimal hydrogen production rate of the most active photocatalyst (0.8 % Ru/CN) was 246 μmol/h without Pt and 1021 μmol/h with Pt, which was more than two times higher than pure g-C3N4. Various physiochemical techniques such as X-ray diffraction (XRD), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL) and transition photocurrent response (PC) were applied to investigate the origin of activity of the Rux/CN photocatalysts. Results indicated that the loading of g-C3N4 with Ru nanoparticles enlarged its surface area and enhanced visible light absorption. Importantly, Ru nanoparticles promoted the charge carrier separation and transfer efficiency of g-C3N4 revealed by the PL and PC measurements, enhancing the photocatalytic activity of the embedded photocatalyst. Furthermore, XPS proved the existence of Ru (II) of RuO2 and metallic Ru0. The Ru-embedded g-C3N4 showed high photocatalytic activity, which makes them attractive materials for further applications in photocatalysis.

Lattice contraction-driven design of highly efficient and stable O–NiFe layered double hydroxide electrocatalysts for water oxidation

The slow progress of the oxygen evolution reaction (OER) is a key challenge in advancing water splitting as a viable technology for sustainable hydrogen production. Utilizing a self-standing NiFe layered double hydroxide (LDH) is a promising approach to address the slow kinetics of OER. Herein, the oxidized Fe2+-containing NiFe-LDH supported on Ni foam (O–NiFe-LDH@NF) is developed through corrosion engineering and aging. The growth mechanism is studied by adjusting urea content, hydrothermal temperature and time. It is revealed that the transformation of Fe2+ to Fe3+ in Fe2+-containing NiFe-LDH and the increase of Fe content leads to lattice contraction. Furthermore, detailed experiments and theoretical simulations illustrate that the substantial Fe content and lattice shrinkage promote the generation of Ni in high oxidation state and enhance the adsorption affinity toward the reaction species. Consequently, O–NiFe-LDH@NF exhibits enhanced OER activity and stability, with an exceptionally low overpotential of 197 mV and 354 mV observed at the current densities of 10 and 500 mA cm−2, respectively, and remarkable stability over 300 h. This approach can be generalized for designing advanced electrocatalysts.

Tetrametallic mastery: Cluster-doped graphdiyne as a superior electrocatalyst for hydrogen evolution

Hydrogen evolution reaction (HER) is a promising route for sustainable hydrogen production. However, its efficiency is limited by kinetic barriers. Herein, we employ density functional theory (DFT) calculations to demonstrate a new strategy of embedding tetrametallic transition metal clusters (3TM1-TM2) into the pores of graphdiyne (GDY) to effectively optimize its HER performance. By screening 900 configurations, 10 prototypes displayed near-ideal hydrogen adsorption free energies. Among them, 3W–Hg@GDY with a ΔGH of −0.00035 eV was identified as the optimal candidate. Analysis of the electronic structure reveals hybridization between the metal d orbitals and GDY p orbitals near the Fermi level, creating partially filled impurity states to promote hydrogen adsorption. Additionally, coordination between the three TM1 atoms and active TM2 atom in the cluster enables precise tuning of TM2's electron density to achieve a moderate interaction with the adsorbed H, facilitating superior HER catalysis. Our findings showcase a new paradigm of cluster engineering for modulating GDY's reactivity that holds great promise as a universal approach for the design of high-performance GDY-based electrocatalysts beyond HER.

Towards sustainable hydrogen production: An integrated approach for Sustainability, Complexity, and Systems Thinking in the energy sector

The energy sector constitutes a dynamic and complex system, indicating that its actions are influenced not just by its individual components but also by the emergent behavior resulting from interactions among them. Moreover, there are crucial limitations of previous approaches for addressing the sustainability challenge of the energy sector. Changing, transforming, and integrating paradigms are the most relevant leverage points for transforming a given system. In other words, nowadays the integration of new predominant paradigms in order to provide a unified framework could aim at this actual transformation looking for a sustainable future. This research aims to develop a new unified framework for the integration of the following three paradigms: (1) Sustainability, (2) Complexity, and (3) Systems Thinking which will be applied to achieving sustainable energy production (using hydrogen production as a case study). The novelty of this work relies on providing a holistic perspective through the integration of the aforementioned paradigms considering the multiple and complex interdependencies among the economy, the environment, and the economy. For this purpose, an integrated seven-stage approach is introduced which explores from the starting point of the integration of paradigms to the application of this integration to sustainable energy production. After applying the Three-Paradigm approach for sustainable hydrogen production as a case study, 216 feedback loops are identified, due to the emerged complexity linked to the analyzed system. Additionally, three system dynamics-based models are developed (by increasing the level of complexity) as part of the application of the Three-Paradigm approach. This research can be of interest to a broad professional audience (e.g. engineers, policymakers) as looks into the sustainability of the energy sector from a holistic perspective, considering a newly developed Three-Paradigm model considering complexity and using a Systems Thinking approach.

Boosting hydrogen production from alkaline water splitting by regulating interlayer stress via lattice mismatch in NiS/MoS2

Alkaline water splitting currently represents one of the most promising routes for sustainable hydrogen production. However, the key challenge with this method lies in the development of low-cost catalysts showing high-performance for hydrogen evolution reaction (HER). Given the rapid advances in the structural design of HER catalysts, a potential procedure to boost their performance is introduced herein. A controllable interlayer stress is generated at the homojunction NiS/NiS interface of electrodeposited hybrid transition metal sulphide NiS/MoS2, by precisely regulating lattice mismatches of NiS nanostructures, achieve a precise control over its charge transfer resistance and the effective balance of electrochemical area. Accordingly, an optimal design, NM5030 (NiS(50 mA/cm2)-NiS(20 mA/cm2)/MoS2/CC), showing an excellent HER performance in alkaline electrolyte is produced. It can drive a high current density of 10 mA/cm2, 100 mA/cm2 and 400 mA/cm2 at a low overpotential of 18 mV, 93 mV and 161 mV, respectively. Under chronoamperometric test, no obvious reduction in current density is observed after 48 h, indicating its high stability. Overall, this work demonstrates the feasibility and effectiveness of the strategy of fabricating lattice mismatch to find an optimal layered structure based catalyst for efficient HER.

FeNi2S4-A Potent Bifunctional Efficient Electrocatalyst for the Overall Electrochemical Water Splitting in Alkaline Electrolyte.

For a carbon-neutral society, the production of hydrogen as a clean fuel through water electrolysis is currently of great interest. Since water electrolysis is a laborious energetic reaction, it requires high energy to maintain efficient and sustainable production of hydrogen. Catalytic electrodes can reduce the required energy and minimize production costs. In this context, herein, a bifunctional electrocatalyst made from iron nickel sulfide (FeNi2S4 [FNS]) for the overall electrochemical water splitting is introduced. Compared to Fe2NiO4 (FNO), FNS shows a significantly improved performance toward both OER and HER in alkaline electrolytes. At the same time, the FNS electrode exhibits high activity toward the overall electrochemical water splitting, achieving a current density of 10mAcm-2 at 1.63V, which is favourable compared to previously published nonprecious electrocatalysts for overall water splitting. The long-term chronopotentiometry test reveals an activation followed by a subsequent stable overall cell potential at around 2.12V for 20h at 100mAcm-2.

Highly dispersed palladium nanoparticles decorated on nitrogen doped graphene for enhanced photoelectrochemical water splitting

Among various clear energy generation processes, electrocatalytic water splitting or hydrogen evolution reaction (HER) has been considered as an efficient method for the sustainable production of hydrogen (H2) fuel. But, significant efforts are still required to develop cheap, effective and stable electrocatalysts for water splitting to achieve the economical production of H2. In the quest of finding cheap electrocatalysts, herein, we demonstrate the preparation of palladium (Pd) nanoparticles decorated nitrogen (N) doped highly reduced graphene oxide (NDG-Pd) based electrocatalysts. The nitrogen (N) doped highly reduced graphene oxide (NDG) was produced by using graphene oxide as precursor, which was reduced and doped with nitrogen, simultaneously in one-step hydrothermal method. Subsequently, Pd nanoparticles were decorated on the surface of NDG using a facile ultrasonic method to produce NDG-Pd. In order to restrict the amount of precious metal to reduce the cost of catalysts, very small percentage of Pd, such as, 1 and 3 % was utilized during the preparation of electrocatalysts. The as-prepared electrocatalysts were successfully characterized by using different methods such as, XRD, XPS, EDX, BET, SEM and TEM. Results confirmed the formation of slightly agglomerated, smaller size of Pd NPs on the surface of NDG with an average particle size of ∼ 6 nm. The as prepared nanocomposites NDG, NDG-Pd1% and NDG-Pd3% were used to prepare electrodes and their electrocatalytic activity was evaluated towards the production of H2 through water splitting. The results of electrochemical performance of as-prepared electrodes within the voltage range have revealed that among different samples prepared, the NDG did not show any current, whereas NDG-Pd3% showed a good potential for HER with current density ≈24 mA/cm2 at very low potential i.e. −0.2 V vs RHE.

Hydrogen Production through Distinctive C-C Cleavage during Acetic Acid Reforming at Low Temperature.

Acetic acid reforming is a green method for sustainable hydrogen production owing to its renewable source from biomass conversion. However, conventional acetic acid reforming would produce various byproducts, including CO, CH4 and so on. Here, we develop a distinctive method for selective hydrogen production from C-C directional cleavage during acetic acid reforming. Completely different from conventional acetic acid reforming process, acetic acid would react with water over organoruthenium catalyst during its C-C cleavage at low temperature, then produce methanol and formic acid (CH3COOH+H2O→CH3OH+HCOOH). Lastly, methanol and formic acid could further decompose into hydrogen and carbon dioxide over organoruthenium selectively. As a result, there is little CO and CH4 produced in the first step of C-C bond cleavage during acetic acid reforming at 100 °C. Hydrogen production rate is up to 26.8 molH2/(h-1*mol-1 Ru) at 150 °C through a tandem catalysis. A mechanism for C-C cleavage of acetic acid is proposed based on intermediate product analysis and density functional theory (DFT) calculation. Firstly, the C-C single bond was transformed into C=C double bond by dropping one H atom to organoruthenium. Then the coming H2O molecule reacted with the C=C bond by an addition reaction, forming methanol and formic acid. This research not only proposes distinctive reaction pathway for hydrogen production from acetic acid reforming, but also provides some inspiration for selective C-C bond cleavage during ethanol reforming.

Tensile nanostructured hierarchically porous non-precious transition metal-based electrocatalyst for durable anion exchange membrane-based water electrolysis

Electrochemical water electrolysis is a promising method for sustainable hydrogen production while transiting towards hydrogen economy. Among many, the Anion Exchange Membrane (AEM) based water electrolyzer is an emerging yet potentially affordable technology on maturity for producing large-scale hydrogen accommodating the usage of Non-Platinum Group Metal (non-PGM) based inexpensive electrocatalysts. Herein, we demonstrate the excellent performance of a bifunctional Nickel Copper Phosphide-Nickel sulphide (NCP-NS) electrocatalyst with a unique tensile nanostructure obtained via a facile, controlled ambient galvanic displacement route. An AEM electrolyzer with a larger active area of 10 cm2 stacked with the symmetric NCP-NS electrodes and a membrane demonstrates scalability with a requirement of a mere 1.66 V to reach a current density of 10 mA cm−2. The nickel-copper phosphide boosts the kinetics of charge transfer between the electrode and electrolyte interface, while a unique combination of a few nickel sulphide phases present in the catalyst provides sufficiently appropriate active sites for the overall water electrolysis. For the first time, we report a room temperature performance of ∼ 230 mA cm−2 at 2 V for a non-PGM-based bifunctional electrocatalyst with exceptional durability for over 300 h of operation in an AEM water electrolyser with a retention rate of 95 %-97 % at a current density range of 80–800 mA cm−2.

Hydrolysis behavior and mechanistic insights of CaMg2InX (X = 0.1, 0.3, 0.5, 0.7) ternary alloy for sustainable hydrogen production

The hydrolysis behavior of CaMg2In0.1, CaMg2In0.3, CaMg2In0.5, and CaMg2In0.7 ternary alloys in an MgCl2 solution following casting and hydrogenation were investigated. The hydrolysis mechanism of these alloys is elucidated through an analysis of microstructure, phase composition, and kinetics before and after hydrolysis. The nucleation-growth Avrami model is employed to accurately model the hydrolysis kinetics, revealing improved hydrolysis yields and reaction rates following hydrogenation. Notably, CaMg2In0.1 has demonstrated exceptional hydrolysis characteristics, exhibiting a yield of 1140 mL/g, an initial hydrolysis rate of 113 mL/g·s, and an activation energy of 24.3 ± 1.7 kJ·mol−1. The yield of H-CaMg2In0.1 further escalates to 1800 mL/g with a rate of 221 mL/g·s, attributed to the formation of Ca4Mg3H14 and In phases subsequent to the hydrogenation of In2Ca and Mg3In phases in the alloy. These newly formed phases act as catalysts and actively participate in the hydrolysis process, providing active sites for hydrogen production, thus enhancing hydrolysis yields and kinetics. It is observed that with increasing In content, the order of hydrolysis performance of the alloy is as follows: CaMg2In0.1 > CaMg2In0.3 > CaMg2In0.5 > CaMg2In0.7, consistent with the trend after hydrogenation. These findings indicate that the addition of In significantly enhances the hydrolysis performance of CaMg2 alloys, offering a promising strategy for preparing magnesium-based alloys with high yields and favorable kinetic properties.

Pd:In-Doped TiO2 as a Bifunctional Catalyst for the Photoelectrochemical Oxidation of Paracetamol and Simultaneous Green Hydrogen Production.

The integration of clean energy generation with wastewater treatment holds promise for addressing both environmental and energy concerns. Focusing on photocatalytic hydrogen production and wastewater treatment, this study introduces PdIn/TiO2 catalysts for the simultaneous removal of the pharmaceutical contaminant paracetamol (PTM) and hydrogen production. Physicochemical characterization showed a high distribution of Pd and In on the support as well as a high interaction with it. The Pd and In deposition enhance the light absorption capability and significantly improve the hydrogen evolution reaction (HER) in the absence and presence of paracetamol compared to TiO2. On the other hand, the photoelectroxidation of PTM at TiO2 and PdIn/TiO2 follows the full mineralization path and, accordingly, is limited by the adsorption of intermediate species on the electrode surface. Thus, PdIn-doped TiO2 stands out as a promising photoelectrocatalyst, showcasing enhanced physicochemical properties and superior photoelectrocatalytic performance. This underscores its potential for both environmental remediation and sustainable hydrogen production.

Enhancing the Hydrogen Evolution Performance of Tungsten Diphosphide on Carbon Fiber through Ruthenium Modification.

Hydrogen-based energy systems hold promise for sustainable development and carbon neutrality, minimizing environmental impact with electrolysis as the preferred fossil-fuel-free hydrogen generation method. Effective electrocatalysts are required to reduce energy consumption and improve kinetics, given the need for additional voltage (overpotential, η) despite the theoretical water splitting potential of 1.23 V. To date, platinum has been acknowledged as the most effective but expensive hydrogen evolution reaction (HER) catalyst. Hence, we introduce a cost-effective (∼2-fold cheaper) ruthenium-modified tungsten diphosphide (Ru/WP2) catalyst on carbon fiber for HER in ∼0.5 M H2SO4, with η ≈ 34 mV at -10 mA cm-2 which can be comparable (only ∼2-fold higher) to benchmark Pt/C (η ≈ 17 mV). The HER performance of WP2 can be enhanced through the modification of ruthenium, as indicated by the electrochemical characterizations. Considering the Tafel value of ∼40 ± 0.2 mV dec-1, it can be inferred that Ru/WP2 follows the Volmer-Heyrovsky reaction pathway for hydrogen generation. Furthermore, the Faradaic efficiency estimation indicates that Ru/WP2 demonstrates a minimal loss of electrons during the electrochemical reaction with an estimated value of ∼98.7 ± 1.4%. Therefore, this study could emphasize the potential of the Ru/WP2 electrode in advancing sustainable hydrogen production through water splitting.

2D Monolayer Catalysts: Towards Efficient Water Splitting and Green Hydrogen Production.

A viable alternative to non-renewable hydrocarbon fuels is hydrogen gas, created using a safe, environmentally friendly process like water splitting. An important role in water-splitting applications is played by the development of two-dimensional (2D) layered transition metal chalcogenides (TMDCs), transition metal carbides (MXenes), graphene-derived 2D layered nanomaterials, phosphorene, and hexagonal boron nitride. Advanced synthesis methods and characterization instruments enabled an effective application for improved electrocatalytic water splitting and sustainable hydrogen production. Enhancing active sites, modifying the phase and electronic structure, adding conductive elements like transition metals, forming heterostructures, altering the defect state, etc., can improve the catalytic activity of 2D stacked hybrid monolayer nanomaterials. The majority of global research and development is focused on finding safer substitutes for petrochemical fuels, and this review summarizes recent advancements in the field of 2D monolayer nanomaterials in water splitting for industrial-scale green hydrogen production and fuel cell applications.

ETFE-grafting ionomers for anion exchange membrane water electrolyzers with a current density of 11.2 A cm−2

In the quest for efficient and sustainable hydrogen production, anion exchange membrane (AEM) water electrolyzers (AEMWEs) have gained significant attention. Development of AEMs has accelerated in the past few decades while the significance of the ionomer on AEMWE performance and durability is always unrecognized. In this study, we proposed a class of electrochemically durable ionomers by introducing the piperidinium group onto the ethylene tetrafluoroethylene (ETFE) backbone using a radiation grafting technology. To avoid disruption of the conformation of the piperidinium group during the functionalization process, we grafted the piperidinium group onto the polymer backbone at the gamma position of the N-piperidinium group using trifluoromethanesulfonic acid as a catalyst. The prepared ETFE-g-poly(styryl propyl piperidinium) ionomers exhibited outstanding electrochemical properties and enhanced alkaline stability. Most notably, the corresponding AEMWEs demonstrated an impressive current density of 11.2 A cm−2 at 2.0 V under 80 °C in 1 M KOH solution. Furthermore, they were continuously operated at a current density of 0.5 A cm−2 for over 300 h with a low voltage decay rate of 0.12 mV h−1. This study offers valuable insights into the development of robust solid-state ionomers through radiation grafting, paving the way for high-performance AEMWEs.