bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of Noble-Metal-Free Membrane Electrode Assemblies Based on Metal Chalcogenides for Electrochemical Hydrogen Production Via Alkaline Seawater Electrolysis
Authors: Ngo Thanh Trung , Arinchtein Aleks , Frisch Marvin , Hager Linus , Buchheister Paul Wolfgang , Kerres Jochen Alfred , Strasser Peter 
Published: September 2023

The production of large amounts of green hydrogen (H2) by electrochemical water splitting represents one of the key pillars to reach net-zero by 2050. As one of the major drawbacks, both low-temperature proton-exchange membrane (PEM) as well as anion-exchange membrane (AEM) electrolysis still rely on the utilization of noble metals in the catalyst layers driving the evolution of H2 and oxygen (O2) on the cathode (HER) and on the anode (OER), respectively. Beyond that, the requirement for highly pure water feeds to prevent degradation of the cell performance over time was previously addressed as one of the main concerns. In particular, this holds true for arid regions located close to the ocean. Advantageously, these coastal arid zones provide essentially unlimited access to seawater, coupled with ample solar irradiation and wind throughout the entire year.[1]
One of the major challenges for direct seawater electrolysis lies in the development of selective catalysts, especially for the anode due to the inherently faster reaction kinetics of the competing two-electron chlorine evolution reaction (ClER). Nickel-iron layered double hydroxides (NiFe-LDH) were identified as active and selective OER electrocatalysts in a previous study[2] by our group. Dionigi et al.[3] recently reported a general design principle for selective seawater electrolysis, in which alkaline pH values > 7.5 are claimed to favor OER over ClER for overpotentials < 480 mV.
At the cathode, state-of-the-art electrolyzers utilize Pt-based catalysts for an efficient HER.[2] For direct seawater electrolysis, however, not only the high cost but also the weak stability due to chloride-induced corrosion restrict the applicability of Pt-based electrodes. In our contribution, we thus present noble-metal free catalyst materials based on metal chalcogenides with high HER activity and improved stability in alkaline seawater electrolyte in a single-cell electrolyzer setup. Membrane-electrode assemblies (MEAs) with superior corrosion-resistance by a modification of the porous transport layers (PTLs) for both cathode and anode will be presented, which outperform reference MEAs containing Pt-based cathodes in alkaline seawater electrolysis. The optimized noble-metal-free electrode design (fig. 1) combined with well-controlled electrolyte feeding enables alkaline seawater electrolysis operating at industrially relevant current densities.

References

[1] S. Dresp, F. Dionigi, M. Klingenhof, P. Strasser, ACS Energy Lett. 2019, 4, 933.
[2] S. Dresp, T. N. Thanh, M. Klingenhof, S. Brückner, P. Hauke, P. Strasser, Energy Environ. Sci. 2020, 13, 1725.
[3] F. Dionigi, T. Reier, Z. Pawolek, M. Gliech, P. Strasser, ChemSusChem 2016, 9, 962.

Figure 1
Autonomous Catalyst Development for Alkaline Electrolysis
Authors: Moretti Enzo , Kiebach Ragnar , Kraglund Mikkel Rykær , Fisker-Bødker Nis , Vegge Tejs 
Published: September 2023

NiFe LDH based materials are promising candidates for cheap, high performance catalysts for alkaline OER. While suffering from degradation effects, the presence of Fe, even in trace amounts, increases their OER activity manifold compared to plain Ni hydroxide. Although discovered in the mid-80s, the exact catalytic mechanism of this “Fe effect” is still not fully understood. Additionally, other doping elements like Co, Cr, Al and others have shown to both further improve OER activity and increase stability. The properties of those materials are often highly dependent on the doping ratio, resulting in an enormous number of possible material combinations. Modern techniques like DFT simulations and machine learning can help to speed up the search for the optimal compositions, but ultimately manual experimentation often limits how fast better materials can be discovered, as the process remains both resource and time-consuming.
In this work, we combine an autonomous high-throughput experiment with machine learning assisted optimization of material compositions to a closed-loop system in an attempt to substantially accelerate the search for high performance alkaline OER catalysts. The system screens an eight variable phase space of doped NiFe LDH for compositions that yield optimal OER performance. Its centerpiece is a 4-axis robotic arm from North Robotics with sample, vial and liquid handling capabilities. The samples are prepared by means of a dip-coating process on Ni foam substrates that allows for doping with different metals. Electrochemical investigations are carried out in 1M KOH in an automated test cell, including EIS, CV and CP measurements at current densities of up to 200mA/cm2. From these results, a figure of merit for the OER activity is calculated and fed into a bayesian optimizer (Dragonfly). This algorithm determines the most promising next test candidate based on the principles of exploration and exploitation and initiates the next experiment accordingly. The experimental procedure can be divided into independent sub-steps, allowing for smart scheduling. This can reduce downtime of the robotic arm and therefore increase the throughput significantly, such that up to 1000 experiments per week can be achieved.
We present the first results of a screening study conducted with this system and compare it to a manual study in terms of accuracy, reproducibility and throughput. Selected, particularly high performing compositions found in this study are also tested in a flow cell setup under industrially relevant conditions (30 wt. % KOH, 60 °C) for several hundred hours.
(Energy Technology Division Supramaniam Srinivasan Young Investigator Award) Fundamental Insights into the Oxygen Evolution Reaction from Epitaxial Oxide Thin Films
Authors: Stoerzinger Kelsey A 
Published: September 2023

The intermittent nature of renewable energy sources requires a clean, scalable means of converting and storing energy. One Earth-abundant storage option is water electrolysis: storing energy in the bonds of O2 and H2, and later extracting electricity by the electrochemical reaction of gasses in a fuel cell. The efficiency of this process is primarily limited by the sluggish kinetics of the oxygen evolution reaction (OER) at the anode, resulting in extensive use of precious metal electrocatalysts in current devices. We have worked to build mechanistic understanding of the OER on benchmark catalysts rutile IrO2 and RuO2, and have investigated competition with the chlorine evolution reaction (CER) in saline feeds, where breaking scaling relations between oxidative processes can broaden the range of acceptable water sources for electrolysis. We have also investigated earth-abundant oxide materials as alternatives, especially nickel-based perovskites, focusing on fundamental understanding of the electrode/electrolyte interface and its relation to catalyst electronic structure.
I will present studies of model oxide electrodes grown by pulsed laser deposition (PLD) and molecular beam epitaxy (MBE) that display a known crystallographic orientation, strain, surface area, and path for charge transport. Such measurements can establish the intrinsic activity of oxide catalysts in a way that cannot be realized with polydisperse nanoparticle systems, and we use these findings to rationally design composition and structure to maximize activity.
Investigation of Surface Chemistry of Pemwes Iridium Oxide Catalyst Layers as a Function of Ink Aging Time
Authors: Foster Jayson , LIU Xiang , Creel Erin , Li Jianlin , Yu Haoran , Cullen David A. , Kariuki Nancy N. , Park Jaehyung , Myers Deborah J. , Serov Alexey , Pylypenko Svitlana 
Published: September 2023

Proton exchange membrane water electrolyzers (PEMWEs) are an advanced and effective solution to producing hydrogen from water for green hydrogen production. To improve PEMWEs operation, it is necessary to analyze the catalyst layer (CL) to better understand relationships between surface properties and processing, performance, and durability. However, understanding the CL composition, structure, and morphology at all relevant scales is difficult. X-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique that is capable of measuring subtle differences in chemistry of a sample’s surface within top 3-10 nms. However, there are several challenges associated with limited information that has been reported in the literature thus far.
This study focuses on investigating the CLs made with IrO2 catalysts using Mayer Bar coating method, one of the scalable fabrication routes. XPS analysis was conducted using a recently developed approach that mitigates issues with degradation of ionomer induced during X-ray exposure. First, XPS was used to probe variations between different areas of the CLs to assess spatial homogeneity to confirm good quality of the coatings. XPS was also employed to investigate CLs made with inks aged for different amount of time (0, 3, and 14 days), noting some differences in the surface chemistry. Results from this study will discuss the effect of ink age on surface composition at the catalyst-ionomer interface, as well as address specific challenges in fitting the O 1s and Ir 4f core level spectra which are inherently challenging to curve fit. This work motivates further studies investigating other aspects related to processing and fabrication as well as investigations of CLs stability.
Anodic/Cathodic Properties of Ni Based Catalysts for Anion Electrolyte Membrane Water Electrolysis
Authors: Kakinuma Katsuyoshi , Shi Guoyu , Tano Tetsuro , Tryk Donald A. , Yamaguchi Miho , Uchida Makoto , Iida Kazuo , Arata Chisato , Watanabe Sumitaka , Iiyama Akihiro 
Published: September 2023

Anion electrolyte membrane water electrolysis (AEM WE) using non-precious metal catalyst is one of the most prospective systems for pure hydrogen generation. The Ni based oxide shows relatively lower overpotential of oxygen evolution reaction (OER) by adding the transition metals of Co, Fe and Mn, and approaches that of precious metal of Ir based oxide. Our previous study reported that the Ni-Co based catalyst was highest OER activity at operating temperature. The crystallized Ni-Co metal-based core particles with amorphous Ni oxyhydrates of top surface (shell) was confirmed to be preferable to obtain the higher OER activity by rotating disk electrode method, transmission electron microscopy and DFT calculation. Moreover, the fused aggregated network microstructure of Ni-Co based catalyst assisted to show a metallically electronic conductivity. In this study, we evaluated both OER and hydrogen evolution reaction (HER) activity of Ni based catalysts to confirm the prospective non-precious metal catalysts for AEM WE.
Each Ni based catalysts with additive of transition metals were synthesized by the flame oxide-synthesis method.1 The OER and HER activities of these catalysts were evaluated in 1 M KOH at 20 to 80 oC by use of the RDE. The Ni-Co based catalyst was highest OER activity in these Ni based catalysts obtained above. The amorphous top surface layer was correlated with a negative shift in the oxyhydroxide formation peak potential from the results of DFT calculations. 2 The HER activity of the Ni-Fe based catalyst also showed the higher OER activity. Especially, the Ni-Fe based catalyst had highest HER activity in these Ni cased catalysts above. The HER activity enhanced by the construction of well crystallized top surface in comparison with its amorphous or poorly crystalline ones. DFT calculation indicated that the defective or disordered surface was not as active for the HER. These results will provide a strategy of Ni based catalysts optimization for AEM.

Acknowledgement

This work was partially supported by funds for the JSPS KAKENHI (20H02839), and the project from the New Energy and Industrial Technology Development Organization (NEDO) of Japan.

References

Kakinuma, M. Uchida, T. Kamino, H. Uchida, and M. Watanabe, Electrochim. Acta, 56, 2881 (2011).

Shi, T. Tano, D. A. Tryk, A. Iiyama, M. Uchida, and K. Kakinuma, ACS Catal., 11, 5222 (2021).

Figure 1
Bifunctional Oxygen Electrocatalysis on Manganese Oxide
Authors: Carlson Evan , Bajdich Michal , Chueh William C. , Mefford J. Tyler 
Published: September 2023

Limited supply of precious metals impedes the scale up of electrolyzer production. To enable 100s of GWs of PEM electrolyzer capacity by 2030, iridium supply must grow by more than 10x.[1] Alternatively, catalysts made of cheaper, more abundant manganese could relieve these constraints, if engineered to have comparable activity and stability. The unique bifunctional OER/ORR activity of Mn oxide could also enable electrolyzers that both produce and consume fuel with a single catalyst. Yet rational design of Mn oxide catalysts requires a better understanding of the structural and chemical motifs that lead to high bifunctional performance.
In this talk, we will discuss our investigation of the bifunctional OER & ORR activity of Mn oxide and its unusual pH dependence. Our model system, 𝛼-KxMnO2, is among the best reported Mn oxide catalysts for both the OER and the ORR, with ORR activity matching that of Pt.[2] While the OER activity of Mn oxide has been shown to increase at higher pH,[3] we will show that its ORR activity improves as well. We will discuss our attempts to understand this phenomenon with operando scanning transmission x-ray microscopy (STXM), which enables spectroscopic investigation of single catalyst particles during reaction with spatial resolution down to 25 nm. Complementary surface DFT calculations provide further evidence for identification of the active crystal facets and insights into the pH-dependency of the OER & ORR mechanisms. We will discuss the implications of this work on the design of bidirectional electrolyzers with low-cost, non-precious metal catalysts.
[1] IRENA. Green Hydrogen Cost Reduction. 2020

[2] Meng, Y. et al.
J. Am. Chem. Soc.
2014, 136 (32), 11452–11464.
[3] Takashima, T. et al.
J. Am. Chem. Soc.
2012, 134 (3), 1519–1527.
Anion Exchange Membrane Electrolyser Performance with Ni Ferrite Anodes Calcined at Different Temperatures
Authors: Caprì Angela , Gatto Irene , Monforte Giuseppe , Lo Vecchio Carmelo , Baglio Vincenzo 
Published: September 2023

Hydrogen has a critical role in enabling European countries to achieve net-zero carbon targets. Hydrogen production via water splitting, using an electrolyser, is considered the "greenest" way because it does not produce any direct carbon emissions when powered by renewable sources. Among the different technologies of electrolysers (liquid alkaline, proton exchange membrane, etc.), there has been a recent surge in interest in that one based on anion-exchange membranes (AEMs). With respect to the state-of-the-art electrolysers that employ conventional acid polymer electrolyte separators (e.g., perfluorinated systems such as Nafion®), electrocatalysis with AEMs is much more promising. Accordingly, inexpensive catalysts can be used.
In this work, NiFe2O4 catalysts are prepared by an "oxalate route". Nickel and iron nitrates in suitable stoichiometric ratios are added in successive steps to the oxalic acid solution. An oxidizing solution of hydrogen peroxide is then added. The obtained precipitate is first filtered and then dried. Different calcination temperatures (350, 450 and 550°C) are applied to obtain the Ni Ferrite with different surface and bulk characteristics. The catalysts are then deposited by a spray technique onto a commercial FAA3-50 (from FuMa-Tech) anion-exchange membrane, combined with a Pt-based cathode electrode, and investigated for the water electrolysis process in a single cell of 5 cm2 geometrical area. A comparison between the performance recorded with the different anode catalysts is reported and discussed.

Acknowledgments

The authors thank the Italian Ministry for University and Research (MUR) for funding through the FISR 2019 project AMPERE (FISR2019_01294).
Performance Losses and Recovery from Cation Contaminants in PEM Water Electrolysis
Authors: Padgett Elliot , Adesso Anthony , Wrubel Jacob A , Pivovar Bryan S. , Alia Shaun M 
Published: September 2023

Water contaminants are extremely common cause of failure for polymer electrolyte membrane (PEM) electrolyzers, potentially accounting for >90% of electrolyzer failures in the field. [1] Water contaminants also commonly impact PEM electrolysis devices in a research setting, confusing measurements of cell performance and durability if they are not recognized and properly addressed. Despite this, relatively little published literature has systematically investigated contaminants in PEM electrolysis cells specifically. Better understanding of contaminant impacts may lead to improved strategies to mitigate or recover performance losses as well as improve the consistency and rigor of electrolysis research.
Here we will present an investigation of the performance impacts of cation contaminants and their recoverability. This investigation focuses on cation contaminants that are abundant in tap/ground water, which may enter the cell through a failure of the water processing subsystem, and transition metals that may leach out of system components. We will report performance impacts for a representative selection of cations as a function of water concentration and accumulated contaminant dose, with impedance spectroscopy used to understand the origin of performance losses. We will also present multiple diagnostic signatures to help identify presence of contaminants in PEM electrolysis cells. Finally, we will address the recovery of cells with different contaminants and the prospects for improved recovery procedures.
[1] Capuano, Chris “Manufacturing Challenges, Opportunities, and Successes for PEM Electrolysis at Scale”, 3rd International Conference on Electrolysis, Golden, CO, 2022.
Photo-Electrochemical Oxygen Evolution Activity in Nickel and Cobalt Antimonates
Authors: Bajdich Michal , Rao Karun K. , Zhou Lan , Yano Junko , Gregoire John M. 
Published: September 2023

Renewable generation of fuels via solar energy offers promising pathways towards sustainable energy future. Its deployment hinges on the discovery of electrochemically durable materials with good solar-to-chemical conversion efficiency. Necessary visible spectrum photoresponse from electrochemically stable materials is however quite rare. On the other hand, the oxygen evolution reaction (OER) requires electrodes that are not only catalytically active, but also stable under harsh electrochemical environments. In this talk, we report on and theoretical understanding of photo-electrochemical behavior an amorphous and crystaline versions of Ni-Sb-Ox and Co-Sb-Ox oxide photoanodes discovered via high-throughput experimental screening [1,2]. The newly discovered amorphous phases meet the requirements of operational stability, visible photoresponse, and appreciable photovoltage. Guided by experimental X-ray absorption characterization of these systems we use density functional theory calculations to perform a prototype phase search to identify a broad family of stable and metastable mixed rutile and hexagonal-like phases for other compositions [3]. Detailed Pourbaix analysis of the identified phases show excellent electrochemical stability, consistent with experimentally measured electrolyte concentrations of photoelectrochemical cells. We analyze when he identified phases form favorable oxygen vacancies formation energies under the reducing synthesis conditions which match measured Ni K-edge x-ray absorption spectra. The calculated OER overpotentials for the most active sites decreases with increasing Ni/Co content, which captures the experimentally observed trend. Stable amorphous metal-antimonates photoanodes are important systems for computational understanding of both the structural and catalytic behavior of these complex oxides and elucidating the co-optimization of photo-electrochemical activity and durability. This material is based on work performed by the Liquid Sunlight Alliance, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under award DE-SC0021266.
[1] Zhou, L., Peterson, E. A., Rao, K. K., Lu, Y., Li, X., Lai, Y., Bauers, S. R., Richter, M. H., Kan, K., Wang, Y., Newhouse, P. F., Yano, J., Neaton, J. B., Bajdich, M., & Gregoire, J. M. Addressing solar photochemistry durability with an amorphous nickel antimonate photoanode. Cell Reports Physical Science, 3(7), 100959. (2022).
[2] Zhou, L., Wang, Y., Kan, K., Lucana, D. M., Guevarra, D., Lai, Y., & Gregoire, J. M. Surveying Metal Antimonate Photoanodes for Solar Fuel Generation. ACS Sustainable Chemistry and Engineering, 21, 33. (2022).
[3] Rao, K. K., Zhou, L., Lai, Y., Richter, M. H., Li, X., Lu, Y., Yano, J., Gregoire, J. M. Bajdich, M., Resolving Atomistic Structure and Oxygen Evolution Activity in Nickel Antimonates, (under review).
(Invited) Preparation of Inexpensive and Efficient Electrocatalysts for Water Electrolysis
Authors: Piao Yuanzhe 
Published: September 2023

Water electrolysis has aroused extensive research efforts due to its potential applications of sewage disposal, microorganism treatment and direct electrolysis for large-scale hydrogen production. In this presentation, I will review our recent progress in the preparation of various electrocatalysts for water electrolysis[1-4]. In search of inexpensive and efficient electrocatalyst for water electrolysis, three strategies to bring out the full potential of the most earth abundant transition metal, iron, are explored: morphology control, secondary metal incorporation, and nitrogen doping.[2] An ultrafast microwave-assisted synthesis of FeMo-MIL-88B followed by self-templated calcination via soft-urea path is developed. The transformed 3D rod-shaped porous iron-molybdenum oxynitride (FeMoON) presents outstanding electrocatalytic performances in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting. The FeMoON electrode affords high current densities of 850 mA-1 at an over- potential of merely 364 mV for OER and 750 mA-1 at an overpotential of 400 mV for HER. The overall water-splitting demeanor surpasses that of commercial noble metal pair in high current densities and shows potential for long-term stability.
[1] Xinyu Qin, Bingyi Yan, Dongwon Kim, Zhishun Teng, Tianyu Chen, Juhyung Choi, Lin Xu* and Yuanzhe Piao*, Interfacial engineering and hydrophilic/aerophobic tuning of Sn4P3/Co2P heterojunction nanoarrays for high-efficiency fully reversible water electrolysis, Applied Catalysis B: Environmental. 2022, 304, 120923.
[2] Yejung Choi, Tianyu Chen, Dongwon Kim, Sang Gu Ji, Hwichan Hong, Lulu Lyu, Myeongseok Jang, Yuanzhe Piao*, Transformation of microwave synthesized highly uniform FeMo-MIL-88B nanorod to oxynitride derivate for overall water splitting reaction, Applied Materials Today, 2021, 24, 101093.
[3] Juhyung Choi, Daekyu Kim, Weiran Zheng, Bingyi Yan, Yong Li, Lawrence Yoon Suk Lee,* Yuanzhe Piao*, Interface Engineered NiFe2O4-x/NiMoO4 Nanowire Arrays for Electrochemical Oxygen Evolution, Applied Catalysis B: Environmental. 2021, 286, 119857.
[4] Liwei Lin, Shuqing Piao,Yejung Choi, Lulu Lyu, Hwichan Hong, Dohyeong Kim, Jeongyeon Lee,* Wang Zhang,* Yuanzhe Piao,* Nanostructured Transition Metal Nitrides as Emerging Electrocatalysts for Water Electrolysis: Status and Challenges, EnergyChem, 2022, 4, 100072.