Article
Electrochemistry
Camillo Spoeri, Cornelius Brand, Matthias Kroschel, Peter Strasser
Summary: The study demonstrates the wide applicability of accelerated degradation testing (ADT) in RDE and CCM measurements, highlighting the advantages of transient operation over static operation for catalyst degradation studies. The suggested ADT-1.6 V protocol allows for quick and accurate assessment of long-term stability of anode catalysts, significantly enhancing degradation research and reliability, while bridging the gap between more fundamental RDE and commercially relevant CCM studies.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Jorge Torrero, Tobias Morawietz, Daniel Garcia Sanchez, Dmitry Galyamin, Maria Retuerto, Vlad Martin-Diaconescu, Sergio Rojas, Jose Antonio Alonso, Aldo Saul Gago, Kaspar Andreas Friedrich
Summary: In this study, an anode with reduced iridium loading (0.2 mg) compared to commercial proton exchange membrane water electrolysis (PEMWE) (2-3 mg) was developed, demonstrating high performance and stability for over 1000 hours. An advanced catalyst based on an Ir mixed oxide (Sr2CaIrO6) was used, which has an unconventional structure that contributes to the reduction of iridium in the catalyst layer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed the reconfiguration of the ionomer in the catalyst layer, resulting in almost full coverage of the catalytic layer with ionomers.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Niklas Trogisch, Max Koch, Ehab N. El Sawy, Hany A. El-Sayed
Summary: Introducing a reliable short-term evaluation procedure for catalyst durability is a major challenge in the development of oxygen evolution reaction (OER) catalysts. Recent studies have shown that the accumulation of microscopic oxygen bubbles within the OER catalyst layer hinders the contact between the electrolyte and the catalyst surface, affecting catalyst dissolution.
Review
Chemistry, Multidisciplinary
Binghui Zhou, Ruijie Gao, Ji-Jun Zou, Huaming Yang
Summary: Hydrogen, a new energy carrier, has promising potential as a replacement for fossil fuels. Using renewable electricity for hydrogen production offers broad prospects for addressing energy and environmental issues. Understanding the mechanisms of electrolytic water reactions and catalysts for water splitting provides a basis for designing and synthesizing highly efficient electrocatalytic materials.
Article
Chemistry, Analytical
Tsukasa Nagai, Zyun Siroma, Tomoki Akita, Tsutomu Ioroi
Summary: The development of a technique to measure electrochemical surface area (ECSA) is crucial for evaluating the activity and durability of Ir-based catalysts for polymer electrolyte membrane (PEM) water electrolysis. Previous methods using mercury underpotential deposition (Hg-UPD) on Ir and IrOx have shown promise for ECSA evaluation, but reproducibility needs to be carefully evaluated due to the Hg(II)/Hg(I) redox reactions and differences in UPD potentials. In this study, the electrochemical behavior of an Ir electrode in a mercury nitrate solution was investigated, confirming the reversible adsorption and desorption of Hg adatoms on the Ir surface at potentials over 0.7V vs the reversible hydrogen electrode. These results contribute to the establishment of a reproducible method for ECSA calculations for Ir-based catalysts.
Review
Chemistry, Physical
Cehuang Fu, Thomas O'Carroll, Shuiyun Shen, Liuxuan Luo, Junliang Zhang, Hui Xu, Gang Wu
Summary: Water electrolysis is the most promising solution for clean hydrogen generation, but its energy efficiency is limited by the slow oxygen evolution reaction (OER), especially in proton exchange membrane (PEM) water electrolyzers. Expensive and scarce Ir-based catalysts are the only candidate for their promising catalytic activity and stability in challenging acidic media. This article highlights recent achievements in developing advanced Ir catalysts with reduced loading and improved performance, as well as the grand challenges and possible innovative strategies.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Chemistry, Physical
Isabel Rodriguez-Garcia, Dmitry Galyamin, Laura Pascual, Pilar Ferrer, Miguel A. Pena, Dave Grinter, Georg Held, Mohamed Abdel Salam, Mohamed Mokhtar, Katabathini Narasimharao, Maria Retuerto, Sergio Rojas
Summary: This study demonstrates that the OER activity and durability of SrRuO3 mixed oxide can be enhanced by partial doping with K+ cations. The doping led to Ru atoms in a higher oxidation state and perovskites with slightly higher symmetry. The K-doped materials showed higher activity and durability, suggesting that chemical modifications can improve the stability of Ru phases during the OER.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Physical
Francesco Bizzotto, Jonathan Quinson, Johanna Schroder, Alessandro Zana, Matthias Arenz
Summary: Water electrolysis is a key technology for transitioning towards a renewable energy system, with iridium being essential for synthesizing catalysts for the oxygen evolution reaction. Research shows that carbon-supported iridium oxide catalysts synthesized from surfactant-free colloidal iridium nanoparticles exhibit high dispersion and activity; the choice of suitable monoalcohol solvent can determine the maximum iridium loading on the support without detrimental particle agglomeration.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Applied
Mark Clapp, Christopher M. Zalitis, Margery Ryan
Summary: Proton exchange membrane water electrolysis (PEMWE) is an important technology for decarbonisation, but its reliance on iridium as a catalyst raises concerns about scalability. This study investigates the future iridium demand of the PEMWE sector and proposes catalyst strategies to improve iridium utilization. Modelling shows that iridium utilization needs to improve significantly by 2050 to avoid supply limitations. Implementing closed-loop iridium recycling would greatly increase installed capacity. Comparisons of different catalysts highlight the importance of stability and efficient iridium utilization. The study concludes that a large-scale PEMWE industry can avoid iridium supply constraints with technological development and increased recycling rates.
Article
Materials Science, Multidisciplinary
Xiaofei Wei, Shoufu Cao, Huakai Xu, Chuanhai Jiang, Zhifei Wang, Yuguo Ouyang, Xiaoqing Lu, Fangna Dai, Daofeng Sun
Summary: In this study, a series of 2D metal-organic frameworks were designed and investigated for their catalytic performance in oxygen reduction and evolution reactions. The CoN2O2 structure showed superior electrocatalytic activity, possibly due to its moderate adsorption interaction with key intermediates.
ACS MATERIALS LETTERS
(2022)
Review
Chemistry, Physical
Sengeni Anantharaj, Subrata Kundu, Suguru Noda
Summary: This article discusses the critical role of Fe in Ni/Co-based OECs in the oxygen evolution reaction, highlighting several contradictory conclusions found in the research. It emphasizes the importance of understanding the Fe effect for efficient hydrogen generation in alkaline medium.
Article
Materials Science, Multidisciplinary
Daniel Boehm, Michael Beetz, Christian Gebauer, Maximilian Bernt, Jonas Schroeter, Matthias Kornherr, Florian Zoller, Thomas Bein, Dina Fattakhova-Rohlfing
Summary: This study presents a facile synthesis method for a highly efficient TiO2 supported iridium oxide based OER catalyst with reduced noble metal content and high conductivity. By controlling phase transformation and crystallization, a catalyst with complex nanostructures, high stability, and increased conductivity was successfully fabricated.
APPLIED MATERIALS TODAY
(2021)
Article
Chemistry, Physical
Aline Bornet, Rebecca Pittkowski, Tobias M. Nielsen, Etienne Berner, Annabelle Maletzko, Johanna Schroder, Jonathan Quinson, Julia Melke, Kirsten M. O. Jensen, Matthias Arenz
Summary: State-of-the-art industrial electrocatalysts for the oxygen evolution reaction (OER) under acidic conditions are Ir-based. In this study, ultrasmall Ir and Ir0.4Ru0.6 nanoparticles were immobilized on two different supports to maximize their dispersion. Surprisingly, the catalysts immobilized on commercial antimony-doped tin oxide (ATO) performed worse than their carbon-immobilized counterparts, suggesting that the ATO support deteriorates particularly fast at elevated temperatures.
Article
Chemistry, Analytical
Xin Luo, Zhen Luo, Xiaoqian Wei, Lei Jiao, Qie Fang, Hengjia Wang, Jinhua Wang, Wenling Gu, Liuyong Hu, Chengzhou Zhu
Summary: A novel template-sacrificed strategy was reported for the synthesis of atomically dispersed Ir SASCs, which were successfully utilized for electrochemical sensing of organophosphorus pesticides with high sensitivity and selectivity. This work demonstrates the broad application prospect of ORR in sensitive detection of biomolecules.
ANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Tsutomu Ioroi, Tsukasa Nagai, Zyun Siroma, Kazuaki Yasuda
Summary: This study investigates the parameters of the rotating disk electrode (RDE) that affect the activity evaluations for the oxygen evolution reaction (OER). Various iridium catalysts are used to examine the impacts of RDE parameters on the measured OER activity in order to obtain the activation polarization accurately. The potential range, catalyst loading, and anions in the electrolyte are found to have a significant impact on the catalytic activity. Comparison of the OER activities of the optimized RDE conditions with those determined using a labo-scale electrolyzer test cell and membrane and electrode assembly (MEA) show consistent results, indicating that the RDE half-cell with proper evaluation conditions can be a useful and rapid initial catalyst screening method to estimate the OER activity in the MEA.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Physics, Applied
Juan-Jesus Velasco-Velez, Lorenz J. Falling, Denis Bernsmeier, Michael J. Sear, Pip C. J. Clark, Ting-Shan Chan, Eugen Stotz, Michael Haevecker, Ralph Kraehnert, Axel Knop-Gericke, Cheng-Hao Chuang, David E. Starr, Marco Favaro, Rik Mom
Summary: In situ x-ray spectroscopies are a powerful tool for studying the electronic structure of the electrode-electrolyte interface, but the design of spectro-electrochemical cells plays a crucial role in determining the measurements and processes that can be studied. It is important to choose the right cell design for the specific process of interest, and understanding the opportunities and limitations of different cell designs through case studies is essential for practical experiments.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Amin Nouri-Khorasani, Arman Bonakdarpour, Baizeng Fang, David P. Wilkinson
Summary: The accumulation of water at the interface between the cathode catalyst layer (CCL) and the diffusion media is a major cause of performance loss in H-2/air fuel cells. This study presents modeling results of water and gas transport across this interface, considering the properties of the carbon material and the microporous layer (MPL). The effects of various factors on the transport phenomena were investigated, providing insights for the rational design of MPL materials.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Juan Jesus Velasco Velez, Denis Bernsmeier, Travis E. Jones, Patrick Zeller, Emilia Carbonio, Cheng-Hao Chuang, Lorenz J. Falling, Verena Streibel, Rik Mom, Adnan Hammud, Michael Haevecker, Rosa Arrigo, Eugen Stotz, Thomas Lunkenbein, Axel Knop-Gericke, Ralph Kraehnert, Robert Schloegl
Summary: Photoelectron spectroscopy is used to investigate electrochemical processes in liquid systems. By comparing with traditional spectroscopic methods, it is found that these approaches provide similar information and have been successfully applied to study the oxygen evolution reaction, revealing the complexity of oxygen speciation. These methodologies also offer new possibilities for investigating electrified solid-liquid interfaces.
FARADAY DISCUSSIONS
(2022)
Article
Electrochemistry
Jason Tai Hong Kwan, Amin Nouri-Khorasani, Arman Bonakdarpour, Daniel G. McClement, Greg Afonso, David P. Wilkinson
Summary: A novel electrolysis flow cell was designed for bubble release experiments, and the performance of different current collectors was evaluated. The correlation between bubble ratio at different frequencies and performance was obtained using Fourier Transform analysis.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Rik Mom, Lorenz J. Falling, Olga Kasian, Gerardo Algara-Siller, Detre Teschner, Robert H. Crabtree, Axel Knop-Gericke, Karl J. J. Mayrhofer, Juan-Jesus Velasco-Velez, Travis E. Jones
Summary: Creating active and stable electrodes is crucial for efficient and durable electrolyzers. This study investigates the factors determining the activity and catalyst dissolution in electrode structures. The researchers found that both surface and near-surface deprotonation play a significant role in the performance of the catalyst.
Article
Chemistry, Multidisciplinary
Bingxin Zhou, Baizeng Fang, Ivan Stosevski, Arman Bonakdarpour, David P. Wilkinson
Summary: This study investigates the application of nano-carbon-based materials in lithium metal batteries and discusses the lithium deposition behavior and deposition location. It is demonstrated that lithium first intercalates into the hollow core of the carbon spheres and then plates on the external carbon walls and coating surface.
Article
Chemistry, Multidisciplinary
Mohana Kante, Moritz L. Weber, Shu Ni, Iris C. G. van den Bosch, Emma van der Minne, Lisa Heymann, Lorenz J. Falling, Nicolas Gauquelin, Martina Tsvetanova, Daniel M. Cunha, Gertjan Koster, Felix Gunkel, Slavomir Nemsak, Horst Hahn, Leonardo Velasco Estrada, Christoph Baeumer
Summary: High-entropy materials show promise as high-activity catalysts for electrochemical energy storage due to their tunability and multiple potential active sites. This study examines the catalytic activity of high-entropy perovskite oxides (HEOs) for the oxygen evolution reaction (OER) and finds that HEOs outperform their parent compounds by a factor of 17 to 680. X-ray photoemission studies suggest that simultaneous oxidation and reduction of different transition metal cations contribute to the high activity of HEOs.
Article
Chemistry, Physical
Nipon Deka, Travis E. Jones, Lorenz J. Falling, Luis-Ernesto Sandoval-Diaz, Thomas Lunkenbein, Juan-Jesus Velasco-Velez, Ting-Shan Chan, Cheng-Hao Chuang, Axel Knop-Gericke, Rik V. Mom
Summary: In the search for rational design strategies for OER catalysts, understanding the link between catalyst structure and activity and stability is crucial. Highly active catalysts like IrO x and RuO x undergo structural changes under OER conditions, requiring consideration of the operando structure of the catalyst. X-ray absorption spectroscopy (XAS) and electrochemical scanning electron microscopy (EC-SEM) were used to study the activation of amorphous and crystalline ruthenium oxide under OER conditions. The data showed that the activation of the oxygen lattice, especially in amorphous RuO x , is key for its high activity and low stability.
Article
Chemistry, Physical
Bingxin Zhou, Ivan Stosevski, Arman Bonakdarpour, David P. Wilkinson
Summary: This study decouples the impedance response of an anode-free lithium metal battery using electrochemical experiments, and finds that the high-frequency and medium-frequency loops are attributed to charge transfer at the solid-electrolyte interface and the plated lithium layers, respectively.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Bingxin Zhou, Ivan Stosevski, Arman Bonakdarpour, David P. Wilkinson
Summary: This study investigates the effects of salt concentration and solvents on the lithium corrosion behavior in anode-free lithium metal batteries (AFLMBs). The results show that increasing salt concentration suppresses chemical corrosion but exacerbates galvanic corrosion. The key to effectively suppressing both types of corrosion lies in promoting the coordination of less-soluble particles and polymers within the solid-electrolyte interface (SEI).
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Adva Ben Yaacov, Lorenz J. Falling, Roey Ben David, Smadar Attia, Miguel A. Andres, Slavomir Nemsak, Baran Eren
Summary: This study uses ambient pressure X-ray photoelectron spectroscopy to investigate the oxidation state of ceria thin film's surface and subsurface under 100 mTorr hydrogen. The influence of initial oxidation state and sample temperature on the interaction with hydrogen is examined. The findings reveal a complex interplay between oxidizing hydride formation, reducing thermal reduction, and reducing formation of hydroxyls followed by water desorption during hydrogen interaction.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Adam L. Gross, Lorenz Falling, Matthew C. Staab, Metzli Montero, Rahim R. Ullah, David M. Nisson, Peter Klavins, Kristie J. Koski, Nicholas J. Curro, Valentin Taufour, Slavomir Nemsak, Inna M. Vishik
Summary: Using ambient pressure x-ray photoelectron spectroscopy, this study reveals the phenomenon of copper migration in CuxBi2Se3, which is accompanied by oxidation of the sample surface and significant changes in selenium content. The results suggest that surface chemical composition of intercalated TIs may change when exposed to ambient conditions.
JOURNAL OF PHYSICS-MATERIALS
(2022)
Article
Chemistry, Physical
Heath Kersell, Moritz L. Weber, Lorenz Falling, Qiyang Lu, Christoph Baeumer, Nozomi Shirato, Volker Rose, Christian Lenser, Felix Gunkel, Slavomir Nemsak
Summary: Nanoparticles can be generated by dopant migration from bulk host lattices. In this study, Ni dopants were found to migrate to the surface of strontium titanate lattices, forming metallic Ni nanoparticles. The morphology of the nanoparticles was observed to change during the migration process.
FARADAY DISCUSSIONS
(2022)