Explore the vast range of titles available.

Proton exchange membrane water electrolysis is a promising technology to produce green hydrogen from renewables, as it can efficiently achieve high current densities. Lowering iridium amount in oxygen evolution reaction electrocatalysts is critical for achieving cost-effective production of green hydrogen. In this work, we develop catalysts from Ir double perovskites. Sr 2 CaIrO 6 achieves 10 mA cm −2 at only 1.48 V. The surface of the perovskite reconstructs when immersed in an acidic electrolyte and during the first catalytic cycles, resulting in a stable surface conformed by short-range order edge-sharing IrO 6 octahedra arranged in an open structure responsible for the high performance. A proton exchange membrane water electrolysis cell is developed with Sr 2 CaIrO 6 as anode and low Ir loading (0.4 mg Ir cm −2 ). The cell achieves 2.40 V at 6 A cm −2 (overload) and no loss in performance at a constant 2 A cm −2 (nominal load). Thus, reducing Ir use without compromising efficiency and lifetime. While water splitting offers a renewable means to produce H 2 fuel, most electrolyzers rely on scarce elements to function. Here, authors study low-content Iridium catalysts derived from mixed oxides for proton exchange membrane water electrolysis anodes without compromising activity and durability.

The production of green hydrogen in water electrolyzers is limited by the oxygen evolution reaction (OER). State-of-the-art electrocatalysts are based on Ir. Ru electrocatalysts are a suitable alternative provided their performance is improved. Here we show that low-Ru-content pyrochlores (R 2 MnRuO 7 , R = Y, Tb and Dy) display high activity and durability for the OER in acidic media. Y 2 MnRuO 7 is the most stable catalyst, displaying 1.5 V at 10 mA cm −2 for 40 h, or 5000 cycles up to 1.7 V. Computational and experimental results show that the high performance is owed to Ru sites embedded in RuMnO x surface layers. A water electrolyser with Y 2 MnRuO 7 (with only 0.2 mg Ru cm −2 ) reaches 1 A cm −2 at 1.75 V, remaining stable at 200 mA cm −2 for more than 24 h. These results encourage further investigation on Ru catalysts in which a partial replacement of Ru by inexpensive cations can enhance the OER performance. Ru-pyrochlores find their way as alternative anodes of PEM water electrolyzers, and their high performance is owing to Ru sites embedded in RuMnO x surface layers. Here, a water electrolyser with Y 2 MnRuO 7 and only 0.2 mgRu cm −2 has been tested with significant durability.

For proton exchange membrane water electrolysis (PEMWE) to become competitive, the cost of stack components, such as bipolar plates (BPP), needs to be reduced. This can be achieved by using coated low-cost materials, such as copper as alternative to titanium. Herein we report on highly corrosion-resistant copper BPP coated with niobium. All investigated samples showed excellent corrosion resistance properties, with corrosion currents lower than 0.1 µA cm−2 in a simulated PEM electrolyzer environment at two different pH values. The physico-chemical properties of the Nb coatings are thoroughly characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). A 30 µm thick Nb coating fully protects the Cu against corrosion due to the formation of a passive oxide layer on its surface, predominantly composed of Nb2O5. The thickness of the passive oxide layer determined by both EIS and XPS is in the range of 10 nm. The results reported here demonstrate the effectiveness of Nb for protecting Cu against corrosion, opening the possibility to use it for the manufacturing of BPP for PEMWE. The latter was confirmed by its successful implementation in a single cell PEMWE based on hydraulic compression technology.

Proton exchange membrane water electrolysis (PEMWE) is the most promising technology for green hydrogen production using renewable electricity, but it is expensive due to the Ti bipolar plates (BPPs). Herein, a PEMWE stack with coated stainless steel (ss) BPPs (Nb/Ti/ss‐BPP and Nb/ss‐BPP) is reported, which operates for about 14 000 h at 1.63 ± 0.12 A cm−2 and 65 °C. The average degradation rate is as low as 1.2% or 5.5 μV h−1. Scanning electrode microcopy reveals no signs of corrosion of the ss beneath the coatings. The interfacial contact resistance increases due to the formation of poorly conductive amorphous Nb oxides, as shown by atomic force microscopy and X‐Ray photoelectron spectroscopy, although it does not affect the cell performance. The results prove that Ti is not needed anymore as base material for manufacturing the BPPs, thus the cost of PEMWE can be significantly reduced. Stainless steel (ss) bipolar plates (BPP) coated with Nb/Ti and Nb for proton exchange membrane water electrolysis (PEMWE) are tested in a commercial stack for almost 14 000 h. No signs of corrosion of the ss substrate can be detected, indicating that ss is a real alternative to pure Ti BPPs contributing to a significant cost reduction of the PEMWE technology.

Anion exchange membranes (AEM) are core components for alkaline electrochemical energy technologies, such as water electrolysis and fuel cells. They are regarded as promising alternatives for proton exchange membranes (PEM) due to the possibility of using platinum group metal (PGM)-free electrocatalysts. However, their chemical stability and conductivity are still of great concern, which is appearing to be a major challenge for developing AEM-based energy systems. Herein, we highlight an AEM with styrene-b-ethylene-b-butylene-b-styrene copolymer (SEBS) as a backbone and pyrrolidinium or piperidinium functional groups tethered on flexible ethylene oxide spacer side-chains (SEBS-Py2O6). This membrane reached 27.8 mS cm−1 hydroxide ion conductivity at room temperature, which is higher compared to previously obtained piperidinium-functionalized SEBS reaching up to 10.09 mS cm−1. The SEBS-Py206 combined with PGM-free electrodes in an AWE water electrolysis (AEMWE) cell achieves 520 mA cm−2 at 2 V in 0.1 M KOH and 171 mA cm−2 in ultra-pure water (UPW). This high performance indicates that SEBS-Py2O6 membranes are suitable for application in water electrolysis.

The global drive for sustainable energy solutions intensified interest in anion exchange membrane water electrolysis (AEMWE), as a promising hydrogen production pathway, leveraging renewable energy sources. However, widespread adoption is hindered by the high cost and non‐optimised design of crucial components, such as porous transport layers (PTL) and flow fields. This study comprehensively investigates the interplay between structure, mechanics, and electrochemical performance of a low‐cost knitted wire mesh PTL, focusing on its potential to enhance cell assembly and operation. Electrochemical characterisation was performed on a single 4 cm2 cell, using 1 M KOH at 60°C. Knitted wire mesh PTL, characterised by approximately 70% porosity, 2 mm thickness, and 1.098 tortuosity, delivered a 33% improvement in current density compared to the standard cell configuration. Introducing a knitted PTL interlayer reduced cell voltage by 74 mV at 2 A cm−2 by improving compression force distribution across the active area, enhancing gas transport and maintaining optimal electrical and thermal conductivity. These findings highlight the significant potential of innovative PTL designs in AEMWE to improve mechanical and operational efficiency without increasing the cost. Porous transport layers (PTLs) play a vital role in enhancing anion exchange membrane water electrolysis (AEMWE) efficiency. This study demonstrates how a cost‐effective, elastic nickel‐based knitted wire mesh PTL improves performance by optimising compression distribution, reducing interfacial resistance, and enabling effective gas transport. These findings offer a pathway to scalable, sustainable hydrogen production without the need for flow fields or platinum group metals.

The durability and performance of electrochemical energy converters, such as fuel cells and electrolysers, are not only dependent on the properties and the quality of the used materials. They strongly depend on the operational conditions. Variations in external parameters, such as flow, pressure, temperature and, obviously, load, can lead to significant local changes in current density, even local transients. Segmented cell technology was developed with the purpose to gain insight into the local operational conditions in electrochemical cells during operation. The operando measurement of the local current density and temperature distribution allows effective improvement of operation conditions, mitigation of potentially critical events and assessment of the performance of new materials. The segmented cell, which can replace a regular bipolar plate in the current state of the technology, can be used as a monitoring tool and for targeted developments. This article gives an overview of the development and applications of this technology, such as for water management or fault recognition. Recent advancements towards locally resolved monitoring of humidity and to current distributions in electrolysers are outlined.

Anion exchange membrane water electrolysis (AEMWE) is one of the most promising candidates for green hydrogen production needed for the de‐fossilization of the global economy. As AEMWE can operate at high efficiency without expensive Platinum Group Metal (PGM) catalysts or titanium cell components, required in state‐of‐the‐art proton exchange membrane electrolysis (PEMWE), AEMWE has the potential to become a cheaper alternative in large‐scale production of green hydrogen. In AEMWE, the porous transport layer and/or micro porous layer (PTL/MPL) has to balance several important tasks. It is responsible for managing transport of electrolyte and/or liquid water to the catalyst layers (CLs), transport of evolving gas bubbles away from the CLs and establishing thermal and electrical connection between the CLs and bipolar plates (BPPs). Furthermore, especially in case the CL is directly deposited onto the MPL, forming a catalyst‐coated substrate (CCS), the MPL surface properties significantly impact CL stability. Thus, the MPL is one of the key performance‐defining components in AEMWE. In this study, we employed the flexible and easily upscaled technique of atmospheric plasma spraying (APS) to deposit spherical nickel coated graphite directly on a low‐cost mesh PTL. Followed by oxidative carbon removal, a nickel‐based MPL with superior structural parameters compared to a state‐of‐art nickel felt MPL was produced. Due to a higher activity of the nickel APS‐MPL itself, as well as improved catalyst utilization, a reduction in cell voltage of 63 mV at 2 A cm−2 was achieved in an AEMWE operating with 1 M KOH electrolyte. This improvement was enabled by the high internal surface area and the unique pore structure of the APS‐MPL with a broad pore size distribution as well as the finely structured surface providing a large contacting area to the CLs.

The demand of green hydrogen, that is, the hydrogen produced from water electrolysis, is expected to increase dramatically in the coming years. State‐of‐the‐art proton exchange membrane water electrolysis (PEMWE) uses high loadings of platinum group metals, such as Pt in the electrode where hydrogen is produced. Alternative electrodes based on phosphides, sulfides, nitrides, and other low‐cost alternatives are under investigation. Herein, a simple process for the preparation of RuP electrodes with high activity for the hydrogen evolution reaction (HER) in acidic electrolyte is described. A straightforward one‐pot synthesis that yields RuP nanoparticles with fine‐tuned composition and stoichiometry is presented, as determined by multiple characterization techniques, including lab‐ and synchrotron‐based experiments and theoretical modeling. The RuP nanoparticles exhibit a high activity of 10 mA cm−2 at 36 mV overpotential and a Tafel slope of 30 mV dec−1, which is comparable to Pt/C. Moreover, a RuP catalyst‐coated membrane (CCM) with a low Ru loading of 0.6 mgRu cm−2 is produced and tested in a PEMWE cell configuration, yielding 1.7 A cm−2 at 2 V. Herein, RuP with high activity for the hydrogen evolution reaction in acidic electrolyte comparable to state‐of‐the‐art Pt‐based catalyst is reported. A pure, stoichiometric RuP is synthesized by a simple one‐pot approach. RuP exhibits an impressive low overpotential of 36 mV at 10 mA cm−2 in rotating disk electrode. The high activity is demonstrated in proton exchange membrane water electrolysis with a low Ru loading of 0.6 mgRu cm−2.

The production of green hydrogen in water electrolyzers is limited by the oxygen evolution reaction (OER). State-of-the-art electrocatalysts are based on Ir. Ru electrocatalysts are a suitable alternative provided their performance is improved. Here we show that low-Ru-content pyrochlores (R MnRuO , R = Y, Tb and Dy) display high activity and durability for the OER in acidic media. Y MnRuO is the most stable catalyst, displaying 1.5 V at 10 mA cm for 40 h, or 5000 cycles up to 1.7 V. Computational and experimental results show that the high performance is owed to Ru sites embedded in RuMnO surface layers. A water electrolyser with Y MnRuO (with only 0.2 mg cm ) reaches 1 A cm at 1.75 V, remaining stable at 200 mA cm for more than 24 h. These results encourage further investigation on Ru catalysts in which a partial replacement of Ru by inexpensive cations can enhance the OER performance.