bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) In Situ Probing of Interfacial Solvation and Electrocatalytic Processes
Authors: Zhang Yingjie
Published: December 2024

Electrochemistry inevitably requires the participation of both the electrodes and the electrolytes, with key processes occurring at the electrode-electrolyte interface. While many tools are available to characterize the electrode structures in situ, the interfacial electrolyte species remain hidden from most existing methods. In this talk, I will discuss my lab’s recent efforts on in situ characterization of the liquid structure at electrified interfaces as well as their impacts on electrocatalysis. On the structural side, we use 3D atomic force microscopy to determine the spatial density profile of the interfacial liquid, and identify layered configurations. As to catalytic activities, we use nanoparticle-enhanced Raman spectroscopy to detect the key oxygen reduction reaction intermediates, in addition to the standard electrochemical tests to quantify the electrolyte effects on the reaction kinetics. The combination of multimodal characterization results provides rich insights into the structure-activity relationship.
Controlling Mass Transport in Direct Carbon Dioxide Zero-Gap Electrolyzers via Cell Compression
Authors: Lee Dong Un (Daniel) , Joensen Bjørt , Jenny Joel , Ehlinger Victoria Marie , Lee Sang-Won , Abiose Kabir , Xu Yi , Sarkar Amitava , Lin Tiras Y , Hahn Christopher , Jaramillo Thomas F.
Published: December 2024

The integration of renewable energy with industrially relevant CO2 electrolyzers provides a promising pathway to achieving sustainable fuels and chemical generation. In this work, mass transport phenomena in a zero-gap membrane-electrode-assembly (MEA) are investigated by varying the thickness of the gaskets used during cell assembly, which in turn determines the overall applied cell compression (Figure 1a). X-ray computed tomography characterization (XCT) shows changes in the gas diffusion electrode (GDE) thickness and porosity as a result of changing the applied cell compression. Using the experimentally measured GDE properties, a computational model of the electrolyzer is developed to study mass transport effects on the performance of the Ag catalyst for CO2 to CO conversion. Applying high cell compression is found to decrease electrode porosity and increase liquid saturation in the cathode catalyst layer and diffusion media, thereby limiting the mass transport of CO2. The two MEAs assembled and tested (MEA-008 and MEA-010) with 0.008” and 0.010” thick gaskets, respectively, show CO Faradaic efficiencies that are very similar to the model results (Figure 1b). MEA-010, which has higher porosity and thicker GDE, outperforms MEA-008 at high current densities (>100 mA cm-2) due to improved mass transport. However, MEA-010 shows increased cell resistance due to the reduced compression of the conductive fibers, resulting in higher operating cell voltages, highlighting the important trade-off between product selectivity and the voltage required to run the electrolyzer.

Figure 1
Ab Initio Dynamics Insights: The Activity and Selectivity of Supercritical CO2 Reduction Reaction on Cu Surfaces
Authors: Li Xiaoyan , Li Jiachen , Ou Pengfei , Xie Ke , Sargent Edward Hartley
Published: December 2024

The electrocatalytic reduction of carbon dioxide (CO2) using renewable energies is widely recognized as a promising approach to establishing a sustainable closed carbon cycle economy. To date, the focus of this field has primarily been on the electrolysis of ambient pressure CO2, where the critical factors include the limited solubility of CO2 in many electrolytes and its hindered mass transport to the electrodes. However, industrial CO2 is typically pressurized during capture, transport, and storage, often existing in dissolved form. Herein, we shift our focus to the potential applications of supercritical CO2 (SCO2) obtained from industrial storage. By using ab initio molecular dynamics simulations integrated with the slow-growth sampling (SG-AIMD) method, we conducted a systematic investigation into the supercritical CO2 reduction reaction (SCO2RR) on various Cu surfaces. Our findings reveal that Cu(111) favors CO* generation, while Cu(100) promotes formic acid production under the reaction conditions of SCO2R. In the meantime, we present a comprehensive free energy diagram incorporating both kinetics and thermodynamics of SCO2 and Cu atom migration, which illustrates the critical role of Cu sites with high coordination numbers induced by intermediate adsorption in the overall performance of CO2 electroreduction into formic acid. This study would lay the foundation for potential applications of supercritical CO2 and the designing of effective catalysts in the future.
The Mechanism and Enhancement of Imidazolium-Mediated CO2 Reduction on Silver in Non-Aqueous Electrolytes
Authors: Coskun Oguz Kagan , Bagbudar Zeynep , Khokhar Vaishali , Dongare Saudagar , Warburton Robert , Gurkan Burcu E
Published: December 2024

Electrocatalysis of carbon dioxide reduction reaction (CO2RR) is known to proceed at lower overpotentials with the presence of ionic liquids (ILs) in the electrolyte. However, the role of ILs in modulating CO2RR, even for the most studied 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) remains unclear. In this study, the electric field and the hydrogen bonding effects induced by [EMIM][BF4] and hydrogen bond donors (HBDs), including water and a series of alcohols, in acetonitrile were examined on Ag. By employing voltammetry, in-situ enhanced Raman spectroscopy (SERS), and density functional theory (DFT) calculations, we reveal that the initial electron transfer to CO2occurs at reduced overpotentials when it is confined between the [EMIM]+ ring planes and the electrode surface. This confinement of CO2 stabilizes it at the interface and enables its conversion to CO, accompanied by the generation of carbene and water as by-products. Furthermore, our findings suggest water (< 0.5 M) acts as the hydrogen bond donor as opposed to serving as the primary source of free protons. Based on this finding, we further show how the extend of hydrogen bonding as varied by various alcohols alter the microenvironment in synergy with [EMIM]+ at the electrode-electrolyte interface for fine tuning of the thermodynamics of CO2RR. The clarified role of the imidazolium based ILs and hydrogen bond donors, and the demonstrated enhancement in CO2RR will advance non-aqueous electrolyte development and inform future kinetic studies.
Understanding the Role of Organic Cations on the Electrochemical Reduction of CO2 in Aprotic Electrolytes
Authors: McGregor Jon-Marc , Bender Jay T , Petersen Amanda S , Canada Louise Marie , Rossmeisl Jan , Brennecke Joan F. , Resasco Joaquin
Published: December 2024

Electrochemical reduction of CO2 (CO2R) offers an appealing way to store intermittent energy produced by renewable electricity sources and sustainably produce chemicals that are currently derived from petroleum. It is well known that CO2R performance is affected by not only the structure and composition of (electro)catalysts but also by the microenvironment surrounding catalytic active sites. The impact of supporting electrolytes on the kinetics of CO2R in aqueous electrolytes has been the subject of many studies. However far less work has been done to understand the influence of the electrochemical environment in non-aqueous solvents for CO2 reduction, despite their favorable physiochemical properties. Here, we describe a physical model that rationalizes the observed influence of choice of organic cation on catalytic performance in non-aqueous electrolytes. Using results from a combination of kinetic, spectroscopic, and computational techniques, we argue that the interfacial electric field present at the catalyst surface is sensitive to the molecular identity of the quaternary organic cation in the electrolyte. In contrast to aqueous electrochemical systems, our results attribute the changes in the reaction energetics for CO generation to differences in the metal-cation distance rather than the change of interfacial cation concentration for solvated alkali metal cations. These findings provide critical insights into the role of electric fields in influencing surface reactivity for critical electrochemical processes. They also provide new tools for the design of selective and efficient electrocatalysts needed for decarbonization of the fuels and chemicals industries beyond the active sites.
(Invited) Investigation of Anion Role during Electrochemical CO2 Reduction on Copper Sulfide (CuS) by Potential-Step Method
Authors: Yamaguchi Akira , Taga Hisanobu , Miyauchi Masahiro
Published: December 2024

One of the candidate materials as CO2 reduction electrocatalysts is metal sulfide, generally because it possesses multiple adsorption sites to overcome scaling relationship. Furthermore, metal sulfide has unique redox property that not only metal sites but anion (sulfur) sites are redox active. To use this property efficiently, this work focused on potential-step method, in which two different electrode potential are applied to an electrode during CO2 reduction process. Previous electrochemical CO2 reduction works using metal copper (K. Kimura et al., ACS Catal., 10, 8632-8639, 2020) and tin sulfide (A. Woldu et al., Angew. Chem. Int. Ed., 62, 2023) electrodes as catalysts clearly demonstrated the usefulness of this method for CO2 reduction, however, its effect on anion behavior and CO2 reduction intermediate is under exploration. In this work, using copper sulfide (CuS) as a model compound, anion role on CO2 reduction reaction by potential-step method on metal sulfide was investigated.

CuS was synthesized with solvothermal method using Cu(NO3)2, thioacetamide, and ethylene glycol as precursor solution. X-ray diffraction (XRD) and Raman measurements revealed that the obtained CuS possesses hexagonal structure. To prepare working electrode, dispersion solution of CuS in water and ethanol containing Sustainion as a binder was dropped onto carbon paper electrode. Electrochemical CO2 reduction properties were examined using H-type cell and 0.1 M KHCO3 aq. as an electrolyte. Platinum mesh and Ag/AgCl (sat. KCl) were used as counter and reference electrodes, respectively.

By applying potential step method, selectivity for formic acid (HCOOH) was increased compared with conventional constant-potential method. XRD and X-ray photoelectron spectroscopy measurement revealed that Cu redox state was changed between Cu0 and Cu+ states during cathodic and anodic potential application, respectively. Furthermore, combining in situ Fourie Transformation Infrared spectroscopy and controlling experiment using Cu0 electrode, Cu2O, and Cu0 in the presence of S2- ion, this work proposed possible intermediate species and how they were affected by anions involved in the reaction to generate specific products. Namely, surface-adsorbed sulfur enhanced the adsorption of H+ ion and contributed to promoting all the reaction, while bulk sulfur stabilized CO intermediate to increase HCOOH selectivity. In addition, existence of oxygen generated Cu+ sites and resulting Cu+/Cu0 interface contributed to producing multi-carbon compounds. Our results indicated that the regulation of anion behavior by potential-step method is one of the promising strategies to control product selectivity of electrochemical CO2 reduction.
Pure-Water-Fed Forward-Bias Bipolar Membrane CO2 Electrolyzer
Authors: Hebelmann Matthias , Lee Jason Keonhag , Chae Sudong , Tricker Andrew , Keller Robert , Wessling Matthias , Su Ji , Kushner Douglas I. , Weber Adam Z. , Peng Xiong
Published: December 2024

Electrochemical CO2 reduction (ECO2R) has emerged as a promising approach to directly produce carbon-containing fuels from renewable sources and CO2, offering a practical opportunity to mitigate greenhouse-gas emissions and climate change. The key challenges to realize this vision are CO2 electrolyzers with high energy efficiency, faradaic efficiency (FE), carbon-conversion efficiency and can also maintain durable operations. As high alkalinity is beneficial for ECO2R reactivity and selectivity, flow cells or zero-gap devices supported by alkaline aqueous electrolytes are used to demonstrate outstanding ECO2R performance. However, this leads to two major challenges. First is the formation of (bi)carbonates (CO3
2-/HCO3
-) and subsequent CO2 crossover issue resulting in either reactant loss or additional energy penalty of regenerating and purifying CO2. Second is that alkali cations transfer through the membrane and build up on the cathode and result in carbonate salt precipitation, which leads to blockage of CO2 transport pathways, efficiency loss and device failure. Therefore, it is an urgent task to develop novel reactions to address both challenges. Herein, we design asymmetrical bipolar membranes assembled into a zero-gap CO2 electrolyzer fed with pure water, solving both challenges. By investigating and optimizing the anion-exchange-layer thickness, cathode differential pressure, and cell temperature, the forward-bias BPM CO2 electrolyzer achieves CO faradic efficiency over 80% with partial current density over 200 mA cm-2 at less than 3.0 V with negligible CO2 crossover. In addition, this electrolyzer achieves 0.61 and 2.1 mV h-1 decay rate at 150 and 300 mA cm-2 for 200h and 100h, respectively. Post-mortem analysis indicates that the deterioration of catalyst/polymer-electrolyte interfaces resulted from catalyst structural change and ionomer degradation at reductive potential shows the decay mechanism. All these results point to future research direction and show a promising pathway to deploy CO2 electrolyzers at-scale for industrial applications.
Electrocatalyst Design for Carbon Dioxide Co-Reduction with Nitrate for Sustainable Synthesis of Urea
Authors: Chen Yu-Han , Roiron Camille , Atanassov Plamen
Published: December 2024

The electrochemical co-reduction of nitrate (NO3
-) and carbon dioxide (CO2) for the synthesis of urea has drawn much research focus recently because it creates value-added products from environmentally hazardous pollutants. Urea is the major ingredient of fertilizer, that is currently produced through the Bosch-Meiser process starting from ammonia (NH3) and carbon dioxide (CO2), in which ammonia is produced through the Haber-Bosch process, leading to significantly high energy consumption and CO2 emissions. Urea electrosynthesis is a complex 16e-, 12H+ transfer reaction with multiple possible by-products such as H2, CO, HCOOH, NO2
-, NH3, etc., making the electrocatalyst design toward urea selectivity a big challenge.

To reliably quantify the urea produced, we present an updated method for urea quantification using the diacetylmonoxime-thiosemicarbazide (DAMO-TSC) method while excluding the interference of NO2
- by-product. We believe this method can guide the electrocatalysis community to establish an updated protocol and avoid false positive/overestimating results.

We will then present a catalyst designed for urea electrosynthesis consisting of Pd nanoparticles in nanoscale proximity to atomically dispersed Fe-Nx sites on a carbon matrix (FeNC). Our group has previously presented Pd nanoparticles and FeNC materials as efficient catalysts for CO2 and NO3
- reduction respectively. Their association at the nanoscale demonstrates over 20% urea faradaic efficiency at -0.5 V (vs RHE) with 100% N-selectivity (All by-products contain nitrogen). These very promising results provide us with the baseline to elucidate the role of individual active sites on the C-N coupling mechanism. To this effect, reaction intermediates of CO2 and NO3
- co-reduction are investigated by in-situ vibrational spectroscopy (Raman, infrared). This study validates the approach of tuning electrocatalysts through mechanistic studies realizing CO2 / NO3
- co-reduction.

Reference:

Murphy, E., Liu, Y., Matanovic, I., Rüscher, M., Huang, Y., Ly, A., Guo, S., Zang, W., Yan, X., Martini, A., Timoshenko, J., Cuenya, B. R., Zenyuk, I. V., Pan, X., Spoerke, E. D., & Atanassov, P. Elucidating electrochemical nitrate and nitrite reduction over atomically-dispersed transition metal sites. Nat Commun 14, 4554 (2023).

Guo, S., Liu, Y., Murphy, E., Ly, A., Xu, M., Matanović, I., Pan, X., & Atanassov, P. Robust palladium hydride catalyst for electrocatalytic formate formation with high CO tolerance. Applied Catalysis. B, Environmental, 316, 121659. (2022).

Huang, Y., Wang, Y., Liu, Y., Ma, A., Gui, J., Zhang, C., Yu, Y., & Zhang, B. Unveiling the quantification minefield in electrocatalytic urea synthesis. Chemical Engineering Journal, 453, 139836. (2023).
Electrochemical CO2 Reduction Reaction to Methanol on a Molecular Cobalt Catalyst
Authors: Menga Davide , Yu Sunmoon , Shao-Horn Yang
Published: December 2024

Our society is currently facing critical challenges regarding CO2 emissions and drastic changes in the way we produce energy, chemicals and materials are required in order to tackle global warming. The electrochemical reduction of CO2 is a key reaction in order to reduce our carbon footprint and a great scientific effort is being made to improve our knowledge and understanding about this complicated process. Recently, cobalt phthalocyanine (CoPc) has drawn tremendous attention due to its capability to electrochemically reduce CO2 and CO to methanol (1-6), a key molecule in the chemical manufacturing industry. Because of its well-defined structure, CoPc provides a model platform to understand reaction mechanism and rationally improve the catalytic activity and stability. In our recent work, through kinetic isotope effect studies and electrokinetic analyses, we identified the protonation of adsorbed CHO as the rate determining step (RDS) for CO2-to-methanol conversion and we showed that the hydration shell of more acidic alkali cations can enhance CO2-to-methanon kinetics via faster proton-coupled electron transfer (in the order Li+ > Na+ > K+ > Cs+). This conclusion was supported by density functional theory calculations and molecular dynamics simulations. In this contribution, the reaction mechanism of CO2-to-methanol electroreduction will be discussed, with a particular focus on how proton-coupled electron transfer kinetics and the stability of reaction intermediates can be tuned in order to maximize the faradaic efficiency for methanol production. Moreover, we will discuss the impact of different reaction conditions on the stability of the CoPc catalyst and possible mitigation strategies will be proposed.

References:

Y. Wu, Z. Jiang, X. Lu, Y. Liang and H. Wang, Nature, 575, 639 (2019).

C. L. Rooney, M. Lyons, Y. Wu, G. Hu, M. Wang, C. Choi, Y. Gao, C.-W. Chang, G. W. Brudvig, Z. Feng and H. Wang, Angewandte Chemie International Edition, 63, e202310623 (2024).

J. Li, B. Shang, Y. Gao, S. Cheon, C. L. Rooney and H. Wang, Nature Synthesis, 2, 1194 (2023).

J. Su, C. B. Musgrave, Y. Song, L. Huang, Y. Liu, G. Li, Y. Xin, P. Xiong, M. M.-J. Li, H. Wu, M. Zhu, H. M. Chen, J. Zhang, H. Shen, B. Z. Tang, M. Robert, W. A. Goddard and R. Ye, Nature Catalysis, 6, 818 (2023).

E. Boutin, M. Wang, J. C. Lin, M. Mesnage, D. Mendoza, B. Lassalle-Kaiser, C. Hahn, T. F. Jaramillo and M. Robert, Angewandte Chemie International Edition, 58, 16172 (2019).

L. Yao, K. E. Rivera-Cruz, P. M. Zimmerman, N. Singh and C. C. L. McCrory, ACS Catalysis, 14, 366 (2024).

Figure 1
Investigating the Influence of Hydrogen Evolution By Copper-Palladium Catalyst on Performance of Zero-Gap CO2 Electrolyzer through in-Situ Raman and Ex-Situ XPS Techniques
Authors: Mishra Mritunjay P.C. , Mishra Mritunjay
Published: December 2024

The electrochemical reduction of carbon dioxide (CO2RR) holds promise for mitigating carbon emissions and reuse CO2 for chemical synthesis and energy storage. Among various catalysts, copper-palladium (Cu-Pd) shows potential for converting CO2 into valuable hydrocarbons (C2+ products). However, the efficiency of Cu-Pd catalysts is hindered by the competing hydrogen evolution reaction (HER) during CO2RR. To tackle this issue, we have developed and analyzed Cu-Pd bimetallic catalysts with varying ratios of copper to palladium to understand the mechanisms underlying HER and its impact on CO2 electrolyzer performance. Utilizing in-situ Surface Enhanced Raman Spectroscopy, Ex-situ Energy Dispersive X-ray Spectroscopy, and X-ray Photon Spectroscopy, we have identified three detrimental effects of HER during CO2 reduction: (i) formation of carbonate salt precipitates causing cathode clogging, (ii) mechanical damage to the ion exchange membrane, and (iii) facilitation of anode catalyst crossover. The precipitation of salts on the cathode flow field and gas diffusion layer hinders CO2 diffusion to the catalyst surface during electrolysis. Notably, we observe catalyst crossover from the anode to the cathode, potentially exacerbating HER during CO2RR. These processes adversely affect the long-term durability of CO2 electrolyzers and necessitate a comprehensive understanding and strategies for mitigation.

Figure 1
Preparation and Characterization of Ni/YSZ-Based Tubular Electrochemical Reactor for SOEC Methanation
Authors: Horiguchi Genki , Yamaguchi Toshiaki , Toriumi Hajime , Tateno Hiroyuki , Bagarinao Katherine Develos , Kishimoto Haruo , Mochizuki Takehisa
Published: December 2024

Co-electrolysis of CO2 and steam using solid oxide electrolysis cells (SOECs) can produce syngas (CO and H2 mixture with various ratios), which is further utilized for the synthesis of hydrocarbon fuels using a catalyst. The combination of SOEC and catalytic fuel synthesis processes can offer an environmentally friendly fuel production process. Ni with yttria-stabilized zirconia (Ni/YSZ) is a typical material utilized for SOEC fuel electrodes. Additionally, Ni metal on YSZ support can also be used as a catalyst for methane production (methanation). In this study, a Ni/YSZ-based tubular electrochemical reactor is developed for the methanation process. The correlations between electrochemical and methanation properties of the prepared reactor will be reported in this presentation.

This study is partly based on results obtained from a project, JPNP21022, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).
Novel Front Contacts for Hydrophobic Gas Diffusion Layers Enable High Energy Efficiency and Durability for Electrochemical CO2 Reduction to C2+ Products.
Authors: Goldman Maxwell , Krall Eric , Marufu Michell , Jaffer Shaffiq A. , Sarkar Amitava , Fleischer Maximilian , Simon Elfriede , Wong Andrew Allen , Baker Sarah
Published: December 2024

Electrochemical CO2 reduction (eCO2R) is an attractive route to mitigate the rise in the global CO2 concentration while producing value-added chemicals. Ethylene (C2H4) is one such product of eCO2R which is an essential industrial precursor with a prominent global market of $230 billion. The large-scale implementation of C2H4-selective CO2 electrolyzers is still challenge due to the low energy efficiencies causes by high ohmic resistances when either employing a hydrophobic gas diffusion layer such as expanded polytetrafluoroethylene (ePTFE), or employing a near neutral catholyte in a single-gap electrolyzer. In this work, we have developed a novel front contact for a CO2 electrolyzer in a zero-gap architecture for electrically insulating gas diffusion layers. This front contact layer allows for incorporating an ePTFE gas diffusion layer while achieving similar full cell voltages as carbon-based gas diffusion electrodes; this configuration also has the added benefits of increased cell stability and selectivity for ethylene. By tailoring the catalyst layer, gas diffusion medium, and operating conditions for a zero-gap ePTFE gas diffusion layer, we were able to achieve a full cell voltage of 2.5 V, with faradaic efficiencies of 48% for ethylene and over 90% faradaic efficiency for reduced carbon species at 200 mA cm-2 and 25 cm2 geometric area cell. This work points towards strategies for developing a scalable, stable, and high energy efficiency eCO2R for C2+ products.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Process Simulations and Technoeconomic Analysis of Ethylene Production By Electrochemical Reduction of Carbon Capture Solutions
Authors: Venkataraman Anush , Song Hakhyeon , Brandão Victor D. , Ma Chen , Salazar Casajus Magdalena , Fernandez Carlos Arturo , Sievers Carsten , Hatzell Marta C. , Bhargava Saket , Arora Sukaran , Villa Carlos , Dhingra Sandeep , Nair Sankar
Published: December 2024

Electrocatalytic reduction offers an alternate route for production of olefins from non-traditional feedstocks such as CO2, resulting in a lower carbon footprint if coupled with renewable sources of energy.Electrolyzer architectures employing bipolar membranes (BPMs) to convert aqueous alkaline carbonates (carbon capture solution) into hydrocarbons are a potential solution to overcome the limitations of high H2 production and crossover rates that limit CO2 conversion in conventional CO2 gas-fed electrochemical systems. Current literature lacks a full process analysis of such a system for C2+ hydrocarbons production, especially the inclusion of direct air capture of CO2 as part of the process and identification of the key tradeoffs involved in such systems. To address this important issue, here we present comprehensive process simulations, process design analysis, and technoeconomic evaluation of integrated electrolysis-based systems (beginning with CO2 capture and ending in electrolyzer product separation and stream recycling) for ethylene production from carbonates. Process simulations revealed the importance of upstream concentration of the captured carbonate feed stream by a membrane system operable at alkaline conditions, which makes the overall process economically feasible. Electrolyzer sizing, scale-up, and configuration are examined in more detail. Costing of the electrolyzer was approached with nonlinear scaling to better account for economies of scale relevant for electrochemical systems. Three different scenarios were considered for a 2 million metric tons (MMT)/yr ethylene plant. A set of key projected performance metrics has been determined for future profitable large-scale production of ethylene from alkaline carbonates. This BPM-based conversion process was evaluated with both direct air capture (DAC) and flue gas capture scenarios for carbonate production, demonstrating roughly equivalent economic feasibility (<8% difference between the 2 cases). Ongoing improvements in BPM-based processes can lead to ethylene minimum selling prices (MSPs) comparable to MSPs from naphtha-based processes, which are also projected to be lower than those of more conventional CO2 gas-fed electrochemical processes.
Reactive Capture of CO2 via Amino Acid
Authors: Xiao Yurou Celine , Sun Siyu , Zhao Yong , Miao Rui Kai , Fan Mengyang , Lee Geonhui , Chen Yuanjun , Gabardo Christine M. , Yan Yu , Qiu Chenyue , Guo Zunmin , Wang Xinyue , Papangelakis Panagiotis , Huang Jianan Erick , Li Feng , O'Brien Colin P. , Kim Jiheon , Han Kai , Corbett Paul J. , Howe Jane , Sargent Edward H. , Sinton David
Published: December 2024

The electrochemical production of carbon monoxide (CO) from carbon dioxide (CO2) has conventionally relied on gas-phase CO2 electrolysis with complex upstream capture and downstream gas separation processes. Reactive capture of CO2 – an integrated approach that combines CO2 capture and electrochemical conversion – uses chemisorbed CO2 directly as the feedstock and thereby avoids CO2 purification and associated costs.

To date, reactive capture has relied on hydroxide-based capture solutions (e.g. potassium hydroxide (KOH)) suitable for direct air capture (DAC) processes or amines (e.g. monoethanolamine (MEA)) that have been conventionally used for point source capture. However, in hydroxide-based systems that capture CO2 in the form of carbonate, the CO Faradaic efficiency (FE) is limited to 50% due to the interaction between in-situ regenerated CO2 and local hydroxides that reduce CO2 availability at the cathode. Amine-based reactive capture can overcome this selectivity challenge when CO2 is captured in the form of carbamate and bicarbonate; compared to carbonate, these forms of chemisorbed CO2 require less electron-coupled protons to regenerate in-situ CO2, and thus yield more CO2 at the cathode. However, conventional amines are volatile and have poor oxygen tolerance, rendering them inapplicable to oxygen-rich CO2-lean conditions.

Here, we report amino acid salt (AAS)-based reactive capture of CO2 that exceeds the CO energy efficiency (EE) achieved in amine- and hydroxide- based systems. The AAS capture solution, potassium glycinate (K-GLY), contains amino functional groups for efficient CO2 capture while offering advantages including oxygen tolerance, low vapor pressure, and low toxicity. We synthesized a nickel single atom (Ni-N/C) catalyst to improve conversion efficiency, optimized the capture solution composition to reduce the electrolysis overpotential at high current densities, and elevated the operating temperature and pressure to increase availability of dissolved in-situ CO2 at the cathode. We achieve CO production with 64% CO FE and a measured full cell voltage of 2.74 V at 50 mA cm-2, resulting in an CO EE of 31% and an energy intensity of 40 GJ tCO-1. The feasibility of the full reactive capture process was demonstrated with both simulated flue gas and direct air input.
Epitaxy Promotes OER Stability of IrO2-Coated SnO2 Nanoparticles in PEM Electrolysis
Authors: Kost Melisande , Kornherr Matthias , Zehetmaier Peter , Gasteiger Hubert Andreas , Döblinger Markus , Fattakhova-Rohlfing Dina , Kost Melisande
Published: December 2024

The transition from fossil fuel-based and CO2-intensive energy production to a future sustainable energy-based economy requires solutions for efficient energy conversion and storage for later re-electrification of green energy from a renewable source such as solar or wind power. One possibility is to convert energy from sustainable sources into chemical energy in the form of hydrogen by electrolysis of water. To meet this challenge, Proton Exchange Membrane (PEM) electrolysis is a powerful, state-of-the-art technology that uses scarce iridium-based catalysts to promote the oxygen evolution reaction (OER). To improve the sustainability and economics of the PEM process, it is necessary to minimize the use of rare and precious iridium to reduce the overall density of iridium-based catalysts for the OER.

Here, we present different strategies for the synthesis of low-total iridium OER catalysts. In addition to the choice of support material and support morphology, we also consider the coating strategy to produce highly active and durable catalysts.

The coating of corrosion-resistant high surface area metal oxide supports of various morphologies with an ultrathin layer of amorphous iridium hydroxide by a simple wet chemical synthesis at low temperature and ambient pressure or by a hydrothermal approach leads to the formation of interconnected amorphous hydrous iridium oxide particles. In a subsequent step, the amorphous phase is oxidized at elevated temperatures using an Adams fusion salt melt. This process allows a controllable phase transformation and crystallization to form a layer of interconnected partially crystalline IrOx nanoparticles of ≈1.5-2 nm domain size on the surface of the supporting metal oxides, thus providing an electrical percolation path in the catalyst layer.

The appropriate choice of support material in terms of crystal lattice parameters can moderate the crystal growth of the iridium oxide in terms of epitaxy and significantly increase the stability due to tight anchoring to the support. The final core-shell nanostructures comprise highly active iridium oxide with total Ir weight fractions as low as 7at% on SnO2 nanoparticles, compared to a state-of-the-art benchmark catalyst with 56at% Ir supported on TiO2 nanoparticles. Transmission electron microscopy (TEM) imaging was used to elucidate the effect of different core-shell designs, particularly on iridium coating and crystallinity. Rotating disk electrode (RDE) measurements were performed to evaluate the electrochemical properties and assess the activity of respective catalyst as well as the cycling stability. Further, membrane electrode (MEA) polarization curves suggest enhanced stability of epitaxial catalyst layers.
Unraveling the Electronic and Geometric Effects in Au-Pt Bimetallic Catalysts: A Comparative Study of Electrodeposition and Sputtering Techniques for Formic Acid Oxidation
Authors: Piwowar Justyna , Lewera Adam
Published: December 2024

A comprehensive investigation into the relationships between the electronic structure of a surface and its catalytic properties is crucial for advancing our understanding of the fundamental mechanisms driving catalytic activity. Platinum and Pt-based systems are widely recognized for their exceptional catalytic performance numerous applications. To elucidate the correlations between electronic configuration and catalytic behavior, we performed a systematic study by depositing gold onto platinum surfaces. The model reaction selected for this investigation was the electrooxidation of formic acid, a reaction of particular relevance due to its role in low-temperature direct formic acid fuel cells (DFAFCs).

The modification of Pt surfaces with Au has been reported extensively in the literature, with numerous studies demonstrating advantageous changes in catalytic properties upon the interaction of these two metals. However, despite the considerable attention this system has garnered, the precise mechanisms underlying these enhancements remain incompletely understood. Two predominant hypotheses have been proposed to explain these phenomena: (1) the geometric effect, whereby changes in surface morphology influence catalytic behavior, and (2) the electronic effect, which posits that alterations in electronic structure, particularly at the metal-metal interface, play a main role.

In our work, we sought to distinguish between these two effects by preparing samples using two distinct methodologies: electrodeposition and sputtering. The electrodeposition technique, by its nature, tends to produce layers that are more likely to exhibit pseudomorphic growth, potentially leading to stronger electronic interactions between the deposited and substrate layers. In contrast, the sputtering method is expected to result in less coherent growth, with potentially weaker interactions. By comparing the catalytic activities of these differently prepared samples, we aimed to discern which effect – geometric or electronic – predominates in the enhancement of catalytic performance.

Comprehensive characterization of the electronic properties of the samples was performed using X-ray Photoelectron Spectroscopy (XPS). Specifically, we focused on analyzing the binding energies of core levels, alongside a detailed investigation of the valence band spectra, paying particular attention to the density of states near the Fermi level and the shifts in the d-band center. These parameters are critical for understanding the electronic interactions at the Au-Pt interface. Additionally, the catalytic activity was studied through cyclic voltammetry (CV), where we observed synergistic effects in the oxidation of formic acid on both types of samples.

Our findings contribute to the growing body of knowledge on the interplay between electronic and geometric factors.
Development of Rapid Diagnostic Platform for Detection of Hepatitis A Virus
Authors: Kaur Dilmeet , Ramasamy Ramaraja
Published: December 2024

Hepatitis A Virus, mainly transmitted through the fecal-oral route by the consumption of infected food and water is known to be a significant public health threat [1]. Most of the cases are underreported given the extended length of time (15-50 days) it takes for symptoms of HAV to appear in infected individuals [2]. The current detection methods are limited in their recovery of the HAV and rely on the viral RNA quantification using qPCR as the wild-type strains of HAV cannot be efficiently isolated and propagated in available cell lines and can take weeks to months to be detected in cell culture. The HAV, inside these cells, makes it difficult to evaluate its infectivity, underlining the need for a more reliable diagnostic device that can directly detect infectious HAV in food and environmental samples. This study presents a method of developing and testing a new electrochemical biosensor that can detect Hepatitis A Virus (HAV) in controlled environments. The biosensor uses FRhK-4 epithelial cells as biological receptors and incorporates a bio-nanocomposite-modified electrode. The surface area of the electrode was optimized by the deposition of gold nanoparticles, resulting in increased cell adhesion and signal strength. The biosensor functions by quantifying changes in electrical impedance caused by the binding of HAV to FRhK-4 cells, which is detected via electrochemical impedance spectroscopy (EIS). The FRhK-4 cells were carefully cultured, and their survival and optimal growth were maintained before immobilizing them on screen-printed electrodes. The biosensor exhibited high sensitivity and specificity in detecting HAV, amongst 2 other non-target viruses, effectively differentiating between various concentrations of the virus. The impedance tests confirm the biosensor's ability to detect and analyze infectious HAV particles, with desirable detection limits, and allow for identifying the target virus even at low concentrations (as low as 10^1 TCID50/mL). A quick, reliable, and precise biosensor for HAV outbreak detection in food production and storage facilities will be a major advance. Improving efficiency and testing different food compositions to ensure greater applicability and integration into food safety processes will be the subsequent steps in this study.

References:

Amon, J.J., Devasia, R., Xia, G., Nainan, O.V., Hall, S., Lawson, B., Wolthuis, J.S., MacDonald, P.D., Shepard, C.W., Williams, I.T. and Armstrong, G.L., 2005. Molecular epidemiology of foodborne hepatitis A outbreaks in the United States, 2003. The Journal of Infectious Diseases, 192(8), pp.1323-1330.

Vaughan, G., Rossi, L.M.G., Forbi, J.C., de Paula, V.S., Purdy, M.A., Xia, G. and Khudyakov, Y.E., 2014. Hepatitis A virus: host interactions, molecular epidemiology and evolution. Infection, Genetics and Evolution, 21, pp.227-243.
Advancements in the Application of 3D Printed Material Towards Electroanalysis
Authors: Bell Jeffrey Gordon
Published: December 2024

The pursuit of reliable and cost-effective sensors for diverse healthcare applications has received significant research efforts with a concerted focus on sensors usable at the point-of-care (POC). A recent and emerging trend in the development of electrochemical sensors is the exploitation of additive manufacturing techniques such as 3D printing, which have numerous advantages such as high precision, rapid fabrication, cost-effectiveness and high degrees of customizability. 3D printing has already made a significant impact on the field of chemistry and is rapidly being utilized in various electrochemical endeavors, ranging from printing electrochemical cells to conductive electrodes. Here, we highlight the advantages of utilizing 3-D printing in the fabrication of i) potentiometric sensors and ii) low-cost and portable amperometric and voltametric sensors for the analysis of electrolytes, pharmaceuticals and biomarkers of human health. Exploiting the versatility of both stereolithography (SLA) and fused-deposition modelling (FDM) 3D printing techniques permits a rapid fabrication and iteration of sensor components and performance. The ability to precisely control the size, shape and thickness of functional 3D printed materials leads to unique opportunities in device design and function.
Qualification and Indexation of Mechanoluminescent (ML) Sensors Toward Crack Monitoring and Visualizing Strain Distribution
Authors: Terasaki Nao , Fujio Yuki , Sakata Yoshitaro , Hirakawa Rio
Published: December 2024

Mechanoluminescent (ML) sensing material is a fascinating ceramic powder (size: av.1 μm, representative ML material: SrAl2O4:Eu2+, lem: 520 nm) and it emits intensive light repeatedly with various type of mechanical stress. The ML luminance is proportional to strain energy. Thus, the two-dimensional (2D) ML emission pattern reflects the dynamical strain/stress distribution.

So far, ML visual sensors has been successfully applied for visualizing crack and mechanical behavior for (1) structural health monitoring (SHM) on infrastructure such as bridge, building, pipe, and hydrogen vessel [1, 2], (2) design and simulation supporting on light-weighting of automobile and airplane [1, 2], and (3) evaluation assisting tools of mechanical testing especially in adhesive joint [3]. In these cases, we have used our synthesized high performance SrAl2O4:Eu2+ as ML material and epoxy resin as matrix pf paint for preparing ML sensors. However, recently, along the big achievements of the ML sensing as above, novel ML sensing material has vigorously investigated and reported, However, there is no standard methods for qualification and indexation of mechanoluminescent (ML) sensors, the candidate user cannot choose appropriate ML sensors for their needs and requirements.

In this presentation, firstly, the achievements of the ML sensing will be introduced, especially the viewpoint of application describe above. Then, we will propose a standard evaluation method of ML sensors using strain (% or mst)-ML luminance (mcd/mm2) curve and express the performance of ML sensor as “ML index”. Finally, we discuss the classification of ML sensor in ML index, to be able users to choose appropriate ML sensor toward crack monitoring and visualizing strain distribution.

This presentation is based on results obtained from a project, JPNP2005, commissioned by the New Energy and Industrial Technology Development Organization (NEDO)

[1] Nao Terasaki, “Direct Visualization of Mechanical Behavior During Adhesive Bonding Failure Using Mechanoluminescence (ML)”, Interfacial Phenomena in Adhesion and Adhesive Bonding, 4, 209-290 (2024), springer. https://link.springer.com/book/10.1007/978-981-99-4456-9

[2] Protecting Infrastructure by Visualizing Stress, NHK WORLD-JAPAN, Science View, https://www3.nhk.or.jp/nhkworld/en/tv/scienceview/20220222/2015274/

[3] ISO8065 ISO/PRF 8065, Composites and reinforcements fibres, Mechanoluminescent visualization method of crack propagation for joint evaluation

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Enhancing Nitrous Oxide Chemiresistive Sensing Performance By Reducing Ionic Oxygen Species Adsorption in Gold Functionalized Tungsten Trioxide Nanofibers
Authors: To Dung Thi Hanh , Yang Bingxin , Myung Nosang V.
Published: December 2024

Low-cost nitrous oxide (N2O) gas sensor is in great need to provide real-time information to various stakeholders. Herein, various gold functionalized tungsten trioxide nanofibers (Au-WO3 NFs) with different composition and crystallinity were synthesized by controlling electrospinning solutions and post heat treatment. These sensing materials were systematically exposed to various N2O concentrations at different operating temperatures (i.e., 250 to 450oC). Among different samples, 1 at. % gold functionalized WO3 nanofibers (1 at. % Au-WO3 NF) annealed at 600oC for 24 hours shows the highest sensitivity (S = Ra/Ro) of 38.5 toward 100 ppm at 250oC with experimentally determined limit of detection (LOD) at 2.5 ppm. Although recovery and recovery time improved, the sensitivity reduced with an increase in operating temperatures. Furthermore, the detailed sensing mechanism studies indicated that the high N2O sensing was achieved when there were limited adsorbed ionized oxygen species (e.g., O-). Moreover, N2O adsorption and desorption activation energy were estimated to be 0.13 and 0.87 eV where desorption was more strongly temperature dependent than adsorption.
Electrochemical Model-Based Capacity Estimation Using Electric Vehicle Driving Data
Authors: Cho Kyeongeun , Kim Sanghyun , Lee Wooju , Choi Jung-Il
Published: December 2024

This study performs capacity estimations based on an electrochemical model using electric vehicle (EV) driving data. Understanding and optimizing the behavior of lithium-ion batteries (LIBs) under varied operational conditions is crucial for improving their performance and reliability. Accurate estimation of the state of an EV battery is critical, and electrochemical models are predominantly used for this internal state estimation. However, these models involve many parameters, leading to computational complexities while minimizing estimation errors. In this study, we introduce a practical parameter identification (PI) approach to address these issues using EV driving data and propose an electrochemical model-based capacity estimation method for EVs.

Despite significant advancements in LIB technology, there remains a gap in the literature, particularly in PI for EV battery packs and the application of driving data. Existing studies mainly focus on controlled laboratory conditions, which do not fully capture the complex and dynamic nature of actual EV usage. This study leverages driving data to bridge this gap, although computational time becomes a considerable challenge when processing hours of driving data for PI. To mitigate this, the study proposes a data under-sampling method that accounts for the applied current and evaluates the accuracy of PI at different sampling intervals (5s, 10s, 20s). Additionally, the identified parameters are analyzed based on the battery's state of charge (SOC).

Capacity estimation using these identified parameters demonstrates an error margin of less than 2%, indicating adequate reflection of the battery's internal state. A comparison of under-sampling intervals reveals that PI at a 20s interval maintains accuracy comparable to that at a 5s interval. The results from PI using data from diverse operational SOC ranges underscore the importance of employing a broad range of SOC values to reflect battery characteristics accurately.
Revisiting the Effect of Interaction between Mobile Ion and Ligand on Phase Evolution and Intercalation Potentials of Berlin Green Cathodes
Authors: Heo Jeong Yeon , Lee Ju-Hyeon , Lee Hyeon Jeong , Lee Ji Hoon
Published: December 2024

Intercalation potentials are affected by many parameters. Among them, they are believed to be primarily determined by the redox potentials of TM ions formed as a result of TM–ligand interactions, especially in oxide-based electrode materials. In this study, we investigate the effects of carrier ions/ligand interaction on the electrochemical potential of host frameworks by utilizing Berlin green (BG; Fe3+[Fe3+(CN)6]) cathodes for Li-ion batteries and Na-ion batteries. When Li- and Na-ions are intercalated into the BG framework, a stepwise reduction of low-spin Fe3+/2+ coordinated with C and high-spin Fe3+/2+ coordinated with N occurs. Notably, cyanide anions interact more strongly with Na-ions than with Li-ions, resulting in different intercalation potentials. In-situ X-ray diffraction, X-ray absorption fine structural analyses, and thermodynamic calculations reveal significant differences in structural evolution and formation energies between lithiated- and sodiated phases (i.e., LixFe2(CN)6 and NaxFe2(CN)6). Especially, as the intercalation content of Na-ion into the BG framework increases, BG undergoes a cubic-to-rhombohedral structural distortion and becomes energetically stable. This study contributes to understanding the tunable structural evolution behaviors and electrochemical potentials of battery electrodes induced by carrier ions–ligand interaction.