bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Layer Deposition of Cu Catalysts on Gas Diffusion Electrodes for Electrochemical CO2 Reduction
Authors: Lee Si Young , Lenef Julia D. , Fuelling Kalyn M. , Rivera Cruz Kevin Enrique , Prajapati Aditya , Delgado Cornejo Daniel O. , Cho Tae H. , Sun Kai , Alvarado Eugenio , Arthur Timothy Sean , Roberts Charles , Hahn Christopher , McCrory Charles , Dasgupta Neil P. 
Published: August 2024

Electrochemical CO2 conversion is gaining attention as an important process for carbon fixation through the use of renewable electricity to address the climate change crisis. Copper is a unique single-element catalyst that can induce C-C coupling reactions to generate high-value-added compounds. The triple phase boundary has been successfully controlled at the catalyst interface using gas diffusion electrodes (GDEs) over the past few years, resulting in high C-C coupling performance. Therefore, methods to engineer the catalyst interface on the 3D structure of GDE are of significant importance. Generally, the catalyst on the GDE is introduced through physical vaper deposition (PVD) using sputtering or E-beam evaporation, or through solution methods such as spray coating and drop-casting of nano-particles. However, the porous and tortuous 3D structure of the GDE often result in limited conformality and difficulty in obtaining a uniform and controlled infiltration of the catalyst into the support structure.
In this study, we synthesized Cu catalysts directly onto GDE surfaces using plasma-enhanced atomic layer deposition (PE-ALD), which allowed for precise tuning of the catalyst size and loading at the nanoscale [1]. The synthesized catalysts were confirmed to be polycrystalline Cu nanoparticles using grazing incidence X-ray diffraction. To demonstrate the advantages of the conformal and tunable control of PE-ALD deposition, we deposited the same areal mass loading of Cu catalyst onto the GDE substrates using PVD, and compared the CO2 reduction activity in an H-cell environment. The PE-ALD Cu catalyst showed more than 3 times higher current density than the PVD catalyst at the same electrode potential, a low (~10%) Faradaic efficiency (FE) for the hydrogen evolution reaction (HER), and greater than 75% FE for C-C coupling to form C2+ products including ethylene and ethanol, which is comparable to the highest performances reported to date for metallic Cu catalysts in a H-cell environment. Furthermore, stable operation was observed for a duration of 15 hours, with minimal changes in activity and selectivity. In conclusion, the introduction of catalysts using PE-ALD on GDE electrodes represents a powerful new synthesis method that can increase both C-C coupling performance and selectivity compared to PVD deposition, due to its adjustable Cu nanoparticle size and high conformality.

Reference

1) J. D. Lenef, S.Y. Lee, K. M. Fuelling, K. E. Rivera Cruz, A. Prajapati, D. O. D. Cornejo, T. H. Cho, K. Sun, E. Alvarado, T. S. Arthur, C. A. Roberts, C. Hahn, C. C. L. McCrory, N. P. Dasgupta, Nano Lett. 23, 10779-10787 (2023)
Mass Transport Regimes in a CO2R Gas Diffusion Electrode Pore with Coupled Microkinetics Model
Authors: Antimes Aymeric , Euzenat Florian , Roy Thomas , Ehlinger Victoria Marie , Govindarajan Nitish , Lin Tiras Y , Sarkar Amitava 
Published: August 2024

Gas Diffusion Electrodes (GDEs) have arisen as a popular CO2 electrolyser configuration due to the improved mass transfer properties and higher current densities possible in comparison to a liquid-fed system. In this work, we aim to understand the mass transport regimes in a single liquid-filled pore of a GDE, i.e., an idealized model of the porous catalyst layer. In previous work, Butler-Volmer (BV) expressions have been used to model the CO evolution reaction and the Hydrogen Evolution Reaction (HER). In this study, we extend that in a few ways: (1) a MicroKinetic Model (MKM) of Au at the surface of the electrode is used instead of the BV expressions, (2) volume/steric effects are incorporated through the Generalized Modified Poisson-Nerst-Planck (GMPNP) equation, and (3) more reactions are considered in the electrolyte. By analyzing pores of varying sizes, following the size distribution measured by Focused Ion Beam Scanning Electron Microscopy (FIB/SEM) in a GDE from the literature, we assess conditions where concentration profiles are no longer effectively one-dimensional in the pore axis. We discuss how these three-dimensional mass transfer effects impact CO2 conversion efficiency. In such regimes, we describe why special treatment is required when calling BV expressions in macroscale pore-averaged models.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL release number: LLNL-ABS-858384.
pH Effects in the Electrochemical Reduction of CO at Cu Electrocatalysts in an MEA Cell Configuration
Authors: Bello Mustapha , Hendershot John C , Dauda Monsuru Olatunji , Park Junghyun , Flake John C. 
Published: August 2024

We explore the impact of pH and buffer on the electrochemical reduction of CO at Cu electrocatalysts in a membrane electrode assembly (MEA) cell. Anolytes included alkaline KOH solution with potassium hydrogen phosphate and potassium dihydrogen phosphate buffers with pH values ranging from 8 to 14. Results show near-neutral pH electrolytes enhance acetate selectivity. Figure 1 shows Faradaic efficiencies to acetate over 85% at a current density of 300 mA/cm². More alkaline electrolytes resulted in increasing HER along with coproduction of ethanol and n-propanol.
Previous works have shown that ethylene production is enhanced at near-neutral pH values and other works have demonstrated that acetate is more favored in alkaline conditions, with ketene identified as a key intermediate. This study highlights the role of phosphate buffers in acetate selectivity at near-neutral pH. SEM, XPS, and XRD analyses show morphological and compositional changes in the Cu catalyst under different pH conditions. We propose that the phosphate buffers stabilize acetate precursors.
Figure 1: Electrochemical performance measurement at different anolyte pH; Faradaic Efficiency of H2, C2H4, CH4, Ethanol, Acetate, and n-Propanol during CO electroreduction in a zero-gap MEA configuration at 300 mA*cm−2.

Figure 1
Impact of Local Environment on Selectivity of Ag and Cu Gas Diffusion Electrodes with Strong Hydrophobic Substrate during the Electrochemical Reduction of CO2
Authors: Bernasconi Francesco , Senocrate Alessandro , Plainpan Nukorn , Battaglia Corsin 
Published: August 2024

Electrochemical CO2 reduction (CO2RR) is a promising pathway to convert detrimental CO2 emissions into sustainable fuels and chemicals, and close the carbon loop1. To ensure the industrial applicability of this technology, electrocatalysts need to be highly active, selective towards a desired product, and offer long-term stability. High activity can be achieved with gas diffusion electrodes (GDEs), in which the CO2 reactant is supplied directly from the gas phase, however reaching high selectivity toward a single product over time remains a challenge. Recently, the control of the local environment around the catalyst has been identified to be a key factor to ensure high selectivity and stability2.
In this work, we show that the local environment around the catalyst drives the selectivity of the catalyst depending on the pore size and hydrophobicity of the GDE. GDEs with large pores and weak hydrophobicity lead to poor selectivity toward carbon products, while GDEs with small pore and strong hydrophobicity yield a greatly improved Faradaic efficiency (FE) towards CO in the case of Ag (FE > 70%)2 and towards C2H4 in the case of Cu (FE > 50%) 3 at 200 mA/cm2 for several hours. The further increase of current density is detrimental to the performance of the GDEs, which points to a limitation of the transport of CO2 to the electrocatalyst. Additionally, CO reduction experiments show a qualitatively similar behavior but at much lower current densities. These findings are consistent with the presence of an electrolyte layer wetting the electrocatalyst that forces the electrocatalytic reaction to take place at double phase boundaries. Finally, we provide evidence for the correlation between the loss of selectivity towards carbon products over time and the precipitation of carbonates by operando synchrotron X-rays diffraction experiments4.
In summary, our results highlight the importance of controlling the local environment near the catalyst to enhance the selectivity towards carbon products during CO2RR.

References

1A. Senocrate, C. Battaglia, J. Energy Storage
2021, 36, 102373

2A. Senocrate, F. Bernasconi, D. Rentsch, K. Kraft, M. Trottmann, A. Wichser, D. Bleiner, C. Battaglia, ACS Appl.
Energy Mater.
2022, 5, 14504

3F. Bernasconi, A. Senocrate, P. Kraus, C. Battaglia, Energy & Environ.
Science Catalysis, 2023, 1, 1009

4F. Bernasconi, A. Senocrate, N. Plainpan, M. Mirolo, Q. Wang, C. Battaglia, submitted
Active Electrode for Ammonia Direct Utilization and the Reactivity of Metal Component in High-Temperature SOFCs
Authors: Horita Teruhisa , Bagarinao Katherine Develos , Kishimoto Haruo , Matsui Toshiaki , Muroyama Hiroki 
Published: August 2024

We have been conducting the international collaboration study on “Green ammonia synthesis and utilization by solid electrolysis cells for maritime application” between Germany and Japan (term:2022-2024) under the SICORP program of Japan Science and Technology Agency (JST). The contributors of this project are AIST, Kyoto University, and Morimura SOFC Technology from Japan side and Fraunhofer IKTS and EDL from German side.
The purpose of this project is to establish a new concept for energy loop based on the ammonia synthesis and utilization with maritime application. The task of Japan side is to make a new anode material for direct utilization of ammonia (cracking and oxidation of NH3 component) and degradation mechanism at anode. Addition of BaO into Ni/YSZ anode improved the decomposition rates of NH3 and anode performance in NH3 fuels. We have succeeded the decomposition rate of NH3 over 99.9 % with an optimum addition amounts of BaO into Ni-YSZ electrode. An excellent performance of BaO-added Ni-YSZ cermet electrode was observed with a stable performance over 80 hours operation.
Preliminary analysis using secondary ion mass spectrometry (SIMS) indicated possible nickel nitride (NiN) formation in the Ni/YSZ substrate of commercial cells exposed to NH3 and possible degradation mechanisms are considered taking into account the thermodynamics and electrochemical oxidation.
This presentation will show the recent progress of this research.
Membrane Electrode Assembly Development for Industrial CO2 Electrolysis
Authors: Hursán Dorottya , Kecsenovity Egon , Danyi Antal , Piszmán Rita , Kovács Anita , Janáky Csaba 
Published: August 2024

Membrane electrode assemblies (MEAs) are the key components of zero-gap CO2 electrolyzers, having various functions in the electrolysis process. The catalyst layers serve as the reaction interface, the porous transport layers ensure reactant and product transport to and from the catalysts, while the membrane is responsible for the ion transport between the two half cells. Thus, the structure of the MEA has a determining role on the electrolyzer operation. Industrial application requires large surface area electrolyzers and / or assembly of stacks. The scale-up, however, imposes different challenges on MEA preparation and on electrolyzer operation, therefore the optimal operating conditions can not necessarily be translated from small-scale (< 10 cm2) experiments.
With the aim to scale-up the CO2 electrolysis to an industrially relevant level (>2500 cm2 active area), we thoroughly study the MEA components in a test electrolyzer cell having 100 cm2 active area. Currently we focus mainly on the optimization of the catalyst layers and the porous transport layers. The used electrolyzer size is already large enough that we can draw relevant conclusions for the operation of the large-scale electrolyzer, however, still offers possibility to screen a wide range of parameters.
I will present selected results on how the improvement of the quality of the catalyst layers - through the optimization of the catalyst ink and the coating process- results in enhanced CO2 reduction performance. We also focus on the screening of different porous transport layers on the anode side with the long-term goal to reduce the precious metal consumption of the CO2 electrolysis. In the second part of my presentation, I will show how the operational parameters (e.g. cell temperature, humidity) affect the stability of the electrolysis. We have thoroughly investigated one of the biggest issues of the anion exchange membrane CO2 electrolysis: the carbonate precipitate formation and the related flooding phenomenon. We identified the pressure drop at the cathode side as a key test output parameter, which can serve as an early warning for the start of the undesired precipitation. When it is recognized in time, and the adequate preventive measures are applied, the lifetime of the electrolyzers can be greatly improved.
Bipolar Membranes for Photoelectrochemical CO2 Conversion
Authors: Cavaliere Sara , Blanchard Pierre-Yves , Spanu Francesco , Nouxet Morgan , Rozière Jacques , Jones Deborah J. 
Published: August 2024

CO2 capture and conversion represent one of the most critical challenges of our society. One sustainable approach to tackle it is the development of electrochemical processes coupling a solar-driven carbon dioxide reduction to CO/water oxidation to O2 with reactions leading tohigh-value products. In such photoelectrochemical reactors, (photo)electrocatalysts and membranes play a crucial role to achieve high CO2 conversion with minimum energy.
The aim of this study is developing polymer membranes with high stability, mechanical resistance and ion conductivity, that can work in the broad pH operation range of CO2/H2O co-electrolysis cells. Consistently with the use of KOH at the anode, the used membrane is often an anion exchange membrane (AEM). However, carbonate crossover through AEM occurs during CO2 electrolysis via diffusion and migration. [1] The use of a bipolar membrane (BPM) allows to mitigate this issue, bringing novel challenges of stability and performance.
The BPM consists in a cation exchange layer (CEL) and an anion exchange layer (AEL), with a bipolar junction formed at their interface. Such membrane must guarantee a constant pH level generating H+ and OH- by water dissociation at the junction, avoid product crossover, and optimize mass transfer and reactivity of coupled anodic and cathodic reactions. A crucial point is the control of the electrochemical behavior at the CEL/AEL interface. With this aim, a 3D-structure made of a network of fibers was developed [2, 3] providing a great interfacial area and mechanical interlocking of the anion and cation exchange ionomers preventing delamination and facilitating the exchange of ions and matter at the interface. Furthermore, such fiber webs allow the controlled deposition of inorganic or organic catalysts to enhance the water dissociation rate at the bipolar junction.
The bipolar membrane was prepared interposing a web of electrospun fibers bearing water dissociation nanocatalysts at the interface between anion and cation exchange polymer layers. The prepared BPMs were characterized for their morphology, composition, ion conductivity, and performance.
This work has been performed with the financial support of the European Union’s Horizon 2020 Research and Innovation Action Program under the project SunCoChem (Grant agreement No 862192).
References
[1] B. Eriksson, T. Asset, F. Spanu, F. Lecoeur, M. Dupont, F.A. Garcés-Pineda, J.R. Galán-Mascarós, S. Cavaliere, J. Rozière, F. Jaouen, J. Electrochem. Soc., 2022, 169, 034508.
[2] R. Sood, S. Cavaliere, DJ. Jones, J. Rozière. Nano Energy, 2016, 26, 729–45.
[3] C. Shen, R. Wycisk, PN. Pintauro. Energy Environ Sci, 2017, 10,1435–42
Recent Advancements in Materials for Proton-Conducting Reversible Solid Oxide Cells
Authors: Luo Zheyu , Zhou Yucun , Kane Nicholas , Zhang Weilin , Hu Xueyu , Liu Meilin 
Published: August 2024

The escalating threats posed by climate change and environmental issues underscore the need for urgent exploration of clean energy technologies. In this context, proton-conducting reversible solid oxide cells (P-RSOCs) have emerged as promising contenders for large-scale energy storage and conversion. Their efficacy at intermediate temperatures (400 - 600 °C) is a distinctive advantage, attributed to the remarkable ionic conductivity of proton conductors within this temperature range. This feature positions P-RSOCs favorably for the efficient, cost-effective, and enduring conversion between clean electricity and green hydrogen.
However, the successful commercialization of P-RSOCs hinges on the rational design of novel materials and meticulous surface/interface modifications to significantly enhance performance and durability. Achieving prolonged durability during cycling between fuel cell and electrolysis modes while maintaining high Faraday efficiency and roundtrip energy efficiency is of paramount importance. A central challenge involves the development of electrolyte materials exhibiting exceptional stability and a high ionic transference number under operating conditions. Additionally, bifunctional electrodes/catalysts, particularly for the oxygen electrode, must demonstrate elevated activity for efficient dual-mode operation.
To effectively tackle these challenges, it is imperative to devise new protocols for controlling the structure, composition, and morphology of materials across multiple length scales. Equally crucial is gaining a fundamental understanding of degradation mechanisms and electrode processes. This presentation will illuminate the critical scientific challenges inherent in developing a new generation of P-RSOCs, providing insights into the latest advancements in electrolyte materials and bifunctional electrodes/catalysts. Furthermore, it will highlight strategies for enhancing durability and electrode activity through surface/interface modification, along with the latest developments in modeling, simulation, and in situ characterization techniques to deepen our understanding of the underlying mechanisms. The presentation will conclude prospects for achieving low-cost, highly efficient, and durable P-RSOCs through innovative material-based solutions.
Understanding Electrochemical and Mechanical Durability of Bipolar Membranes Used in Electrodialysis
Authors: Crow Allison M , Deutsch Todd G , Smith Wilson A 
Published: August 2024

Using renewable energy to drive direct carbon capture systems is a powerful way to contribute to net negative emissions. When using liquid alkaline sorbents for CO2 direct air capture, it is critical to reduce the energy demand for CO2 concentration and sorbent regeneration. Electrodialysis is an ideal candidate technology to integrate renewable energy into this process, however, to enable this ion-exchange membrane separators that can operate at high ion flux and low voltage are needed. Bipolar membranes (BPMs), that generate protons and hydroxide ions from the dissociation of water when operated in reverse bias, are the enabling component to generate acid and base in electrodialysis systems. Bipolar membrane electrodialysis (BPMED) uses a BPM to create acidifying and basifying chambers which are well suited to concentrate and release CO2 and concentrate the remaining alkaline effluent to cycle back to the capture process. Current BPM durability, however, sufferers at high current density (ion flux) and physical scale. BPMs have several known degradation mechanisms including chemical breakdown of ion exchange polymers, loss of junction adhesion, or physical breakdown due to shearing force and pressure swings in an electrodialysis cell.
To assess the electrochemical and mechanical durability of BPMs under operational conditions, we investigated how fabrication conditions (including preconditioning, hot pressing, and catalyst loading) impact the adhesion of custom made BPMs. T-peel studies were performed ex-situ to quantify adhesive forces of BPMs made of different compositions and prepared under different conditions, and BPMED experiments were performed to assess the electrochemical performance of the corresponding BPMs. The BPMED results show that, while adhesion is necessary to physically maintain the BPM junction, mechanical adhesion alone cannot overcome poor ion and water transport management at the water dissociation junction. The results of this systematic comparison indicate that in order for BPMs to operate at high current densities, high adhesion forces made during fabrication of BPMs will need to be balanced with water dissociation kinetics and ion/water transport through the individual membrane layers.
Impact of Mechanical Stimuli on PEO-Litfsi Stiffness and Ionic Conductivity
Authors: Garcia ThomasJae , Elcombe Gregory , Lee Min Hwan 
Published: August 2024

Recently a large emphasis has been placed on developing safer electrolytes for lithium-ion batteries as a response to an increase in battery demand. Solid polymer electrolytes, such as those based on polyethylene oxide (PEO) show good resistance to mechanical loading, and when coupled with ceramic fillers demonstrate enhance ionic conductivity as well. Prior to this work, efforts have been made to determine the effects mechanical stimuli have on the stiffness and ionic conductivity of the electrolyte.1–3 However, while previous research has primarily focused on bulk EIS measurements of the electrolyte, here we leverage atomic force microscopy (AFM) to modulate the tip-substrate contact force from a few piconewtons to tens of millinewtons to study the correlation between mechanical loading and ionic conductivity, along with measuring the evolution of the substrate stiffness as a function of mechanical cycling.
In this study, we contact the PEO-LiTFSI surface with an electrically conductive Pt-coated tip and mechanically cycle the sample by applying a pre-determined contact force a set number of times. By keeping the contact force and time constant, we extracted the cycle-dependent evolution of the sample stiffness. Results show that stiffness is reduced 30% within the first ten cycles, and then minimally changes with subsequent cycling, matching the results from bulk measurements. Changes in ionic conductivity as a function of mechanical cycling are then measured using electrical characterization techniques. To gain a better understanding of how conductivity and stiffness are evolving, we conducted a parametric study by varying tip size, contact force, and number of mechanical cycles. From early results, we found that electrical resistance increases by ~3% (from 2985 Ohm to 3075 Ohm) after 100 cycles of mechanical force ranging between ~ 0 nN to 450 nN with a 5 µm radius tip. The change in the electrical resistance is believed to originate from the local amorphization of PEO-LiTFSI induced by the mechanical stimuli and resulting change of the local conductivity. These results can be leveraged to further understand how mechanical stimuli affects the mechanical and electrical characteristics of solid electrolytes and help establish a model to predict long-term stability and performance of batteries.
This work was supported by the National Science Foundation (#2125640).
(1) Yoon, D. et al., ACS Appl. Energy Mater, 6 (18), 9400, 2023
(2) Li, X. et al., ACS Appl. Mater. Interfaces, 11 (25), 22745, 2019
(3) Liu, L. et al., Nano Energy, 69, 104398, 2020