ACS electrochemistryPub Date : 2025-03-14eCollection Date: 2025-05-01DOI: 10.1021/acselectrochem.4c00171
Zamaan Mukadam, Sihang Liu, Soren B Scott, Yuxiang Zhou, Georg Kastlunger, Mary P Ryan, Maria Magdalena Titirici, Ifan E L Stephens
{"title":"Direct Electrosynthesis of an Amino Acid from a Biomass Derivative.","authors":"Zamaan Mukadam, Sihang Liu, Soren B Scott, Yuxiang Zhou, Georg Kastlunger, Mary P Ryan, Maria Magdalena Titirici, Ifan E L Stephens","doi":"10.1021/acselectrochem.4c00171","DOIUrl":"https://doi.org/10.1021/acselectrochem.4c00171","url":null,"abstract":"<p><p>The electrochemical synthesis of nitrogen-containing molecules from biomass-derived compounds under ambient conditions is demonstrated, relying only on green sources of feedstock, renewable energy, and water. In this study, we report a two-step method of electrochemically synthesizing 5-(aminomethyl)furan-2-carboxylic acid (AFCA) from 5-hydroxymethylfurfural (HMF) using hydroxylamine (NH<sub>2</sub>OH) as the nitrogen source in an acidic electrolyte. In the first step, HMF was reductively aminated into (5-(aminomethyl)furan-2-yl)methanol (HMFA) using NH<sub>2</sub>OH as the source of nitrogen. This was followed by a second step, involving the oxidation of HMFA to AFCA on a manganese oxide (MnO <sub><i>x</i></sub> ) anode at the same pH. MnO <sub><i>x</i></sub> was able to selectively oxidize the alcohol group on HMFA to produce AFCA with 35% Faradaic efficiency without affecting the amine group. As both of these reactions are completed in a pH 1 electrolyte, it eliminates the need to separate HMFA before proceeding with the second reaction. Among different metal electrodes (Ag, Au, Cu, Pb, Pt and Sn) tested for the electrochemical reductive amination reaction, Ag electrodes displayed the best performance to selectively aminate HMF to the intermediate species, HMFA, with up to 69% Faradaic efficiency at mild potentials of -0.50 V<sub>RHE</sub>. Density functional theory calculations were carried out to explore a possible reaction pathway for the reductive amination on Ag(111), which suggests a thermodynamically feasible reaction even at 0 V<sub>RHE</sub>. The cathodic experimental reaction parameters were optimized to reveal that an electrolyte pH of 1 is optimal for the electrochemical reductive amination reaction. Our work shapes the future possibility of an electrochemical synthesis to produce AFCA without the need for any product separation between steps by combining the Ag cathode reaction to the MnO <sub><i>x</i></sub> anode reaction sharing the same electrolyte. Since both the cathode and anode reactions both involve four electrons transferred, combining both half reactions in a single electrochemical reactor can eliminate the need for energy-wasting auxiliary counter reactions such as hydrogen evolution or water oxidation.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 5","pages":"699-708"},"PeriodicalIF":0.0,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12051197/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144036114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-03-06Epub Date: 2024-11-22DOI: 10.1021/acselectrochem.4c00068
Audrey Pumford, Lindsey M Pumford, Abigail Butcher, Ryan J White
{"title":"Measuring the Effects of Tunable Alkanethiol Monolayers on the Adsorption and Collision Dynamics of Platinum Nanoparticles.","authors":"Audrey Pumford, Lindsey M Pumford, Abigail Butcher, Ryan J White","doi":"10.1021/acselectrochem.4c00068","DOIUrl":"10.1021/acselectrochem.4c00068","url":null,"abstract":"<p><p>Platinum nanoparticles (PtNPs) catalyze the Hydrogen Evolution Reaction upon colliding at a catalytically inactive electrode surface when sufficient potential is applied, and in the presence of adequate hydrogen ion concentration. Here, we investigated nanoscale interactions of PtNPs at alkanethiol modified gold electrode surfaces and examined the effects of monolayer hydrophilicity/hydrophobicity on single particle collision dynamics. After colliding with and adsorbing onto the modified electrode surface, PtNPs generate measurable cathodic current arising from the reduction of hydrogen. Each single particle collision is indicated by a spike-step or spike of current in the current time trace. The shape, frequency, and size of these current steps are dependent on the terminal chemistry of the alkanethiol covalently bound to the electrode surface. Using the collisional frequency as a function of PtNP concentration, we determined the rate of particle adsorption, <math> <msub><mrow><mi>k</mi></mrow> <mrow><mtext>ads</mtext></mrow> </msub> </math> , to be 2.23 × 10<sup>-6</sup> cm/s and 8.85 × 10<sup>-6</sup> cm/s for -CH<sub>3</sub> and -OH terminated surfaces, respectively. Electrodes modified with a mixture of alkanethiols (-CH<sub>3</sub>/-OH) exhibited collision frequencies that scale linearly with the ratio of hydrophilicity of the alkanethiol immobilized on the electrode surface. The results indicate the dependence of intermolecular effects on PtNP collision dynamics at the electrode surface, with hydrophobic-dominating surfaces having the least observed collisions. This study provides insights into the influence of surface chemistry on single nanoparticle interactions, which could advance the designs of biosensors and more efficient nanocatalysts by offering a deeper understanding of the interfacial mechanism of PtNPs on modified electrode surfaces.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 3","pages":"378-385"},"PeriodicalIF":0.0,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12014222/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144049261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-03-03eCollection Date: 2025-07-03DOI: 10.1021/acselectrochem.4c00226
Saeid Behjati, Marc T M Koper
{"title":"Effect of Trace Amounts of Chloride on Roughening of Au(111) Single-Crystal Electrode Surface in Sulfuric Acid Solution during Oxidation-Reduction Cycles.","authors":"Saeid Behjati, Marc T M Koper","doi":"10.1021/acselectrochem.4c00226","DOIUrl":"10.1021/acselectrochem.4c00226","url":null,"abstract":"<p><p>This study investigates the impact of varying trace-level chloride ion concentrations on the roughening of a Au(111) electrode during oxidation-reduction cycles (ORCs) in 0.1 M sulfuric acid by in situ scanning tunneling microscopy (STM). At the higher chloride concentration (50 μM), rapid dissolution of Au atoms and step line recession are observed in the recorded in situ STM images. The high surface mobility of Au atoms resulted in a lack of detectable vacancy islands in the images with minimal changes in cyclic voltammograms (CVs) and the complete absence of nano-island formation, which is observed in pure sulfuric acid. At moderate concentration (10 μM), the dissolution rate decreased substantially, so the initial step lines are still distinguishable after the 200 ORCs. The lower surface mobility leads to the formation of vacancy islands in the terraces, and these newly formed step sites give rise to additional peaks in the CVs. At the lowest concentration (1 μM), nano-island formation is observed. However, inhomogeneous chloride adsorption (showing as darker areas in the EC-STM images) on the sample at high enough anodic potential (0.9 V) led to previously unreported behavior, showing very inhomogeneous roughening, with parts on the surface showing reduced Au atom mobility and minimal changes even after 200 ORCs.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 7","pages":"1082-1092"},"PeriodicalIF":0.0,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235628/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144602698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-28eCollection Date: 2025-06-05DOI: 10.1021/acselectrochem.4c00230
Adam J Lovett, Máté Füredi, Liam Bird, Samia Said, Brandon Frost, Paul R Shearing, Stefan Guldin, Thomas S Miller
{"title":"Structural Evolution of Silicon Nitride Anodes during Electrochemical Lithiation.","authors":"Adam J Lovett, Máté Füredi, Liam Bird, Samia Said, Brandon Frost, Paul R Shearing, Stefan Guldin, Thomas S Miller","doi":"10.1021/acselectrochem.4c00230","DOIUrl":"10.1021/acselectrochem.4c00230","url":null,"abstract":"<p><p>Silicon nitride (SiN <sub><i>x</i></sub> ), a conversion-alloying lithium-ion battery electrode with excellent potential to replace silicon and graphite anodes, offers improved cycle stability and fast-charging capabilities. During the formation cycle(s), SiN <sub><i>x</i></sub> irreversibly converts into a mixture of lithiated silicon and nitridosilicate matrix. However, beyond this basic understanding, there is limited fundamental insight into how the post-conversion structure results in improved electrochemical performance. This significantly hinders the optimization and commercialization prospects of SiN <sub><i>x</i></sub> anodes. Herein, <i>operando</i> electrochemical atomic force microscopy is used to uncover the morphological and chemo-mechanical changes of SiN <sub><i>x</i></sub> thin films during the conversion reaction. We elucidate that the post-conversion SiN <sub><i>x</i></sub> forms silicon domains embedded within a matrix with a core-shell-like structure comprised of a stiff outer nitridosilicate surface and softer inner Si-rich core. The silicon domains that form have very stable dimensions (∼100 nm in diameter) that, crucially, remain smaller than the critical cracking threshold of silicon. This results in a more mechanically robust anode, anticipated to be free from the adverse effects of cracking, pulverization, and subsequent capacity fade. Our work marks an important advance in the fundamental understanding of silicon nitride anodes and offers a pathway to their incorporation into next-generation batteries.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 6","pages":"962-973"},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147161/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-26eCollection Date: 2025-06-05DOI: 10.1021/acselectrochem.4c00219
Emer B Farrell, Fionn McNeill, Dominik Duleba, Adria Martínez-Aviño, Patrick J Guiry, Robert P Johnson
{"title":"Determination of Enantiomeric Excess in Confined Aprotic Solvent.","authors":"Emer B Farrell, Fionn McNeill, Dominik Duleba, Adria Martínez-Aviño, Patrick J Guiry, Robert P Johnson","doi":"10.1021/acselectrochem.4c00219","DOIUrl":"10.1021/acselectrochem.4c00219","url":null,"abstract":"<p><p>The validation of the stereochemical purity of synthesized compounds is a requisite for the fine-chemical industry, particularly in the production of enantiopure drug compounds. However, most methodologies employed in the determination of enantiopurity require carefully chosen chiral GC or HPLC columns, increasing associated cost, analysis time, and complexity. Herein, we present a nanopore-based technology for the determination of enantiopurity, exploiting changes in ion-current rectification of quartz nanopipettes containing an aprotic organic electrolyte. Changes in solvent ordering at the quartz surface upon enantiomerically preferential adsorption give rise to distinguishable current-voltage responses. The applicability of our simple and cost-effective platform is demonstrated through the determination of the enantiomeric excess of commercially available (<i>R</i>)- and (<i>S</i>)-enantiomers of 4-methoxy-α-methylbenzylamine and duloxetine hydrochloride, as well as the product of a decarboxylative asymmetric allylic alkylation. Ion-current rectification (ICR)-based enantiomeric excess determination is completed within minutes, using negligible sample volumes and with simple low-cost electrical instrumentation.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 6","pages":"928-939"},"PeriodicalIF":0.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147146/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-18eCollection Date: 2025-05-01DOI: 10.1021/acselectrochem.4c00186
Daniela Carmona-Pérez, Meiqin Gao, Samantha Andes, William W Brennessel, Agnes E Thorarinsdottir
{"title":"Effect of Coordination Environment and Electronic Coupling on Redox Entropy in a Family of Dinuclear Complexes.","authors":"Daniela Carmona-Pérez, Meiqin Gao, Samantha Andes, William W Brennessel, Agnes E Thorarinsdottir","doi":"10.1021/acselectrochem.4c00186","DOIUrl":"https://doi.org/10.1021/acselectrochem.4c00186","url":null,"abstract":"<p><p>The elucidation of factors that govern the temperature sensitivity of the electrochemical potential is essential to the development of electrochemical systems with target properties. Toward this end, we report a series of isostructural homo- and heterometallic M<sub>2</sub> (M = Fe<sup>II</sup>, Fe<sup>III</sup>, Zn<sup>II</sup>) complexes supported by a phenoxo-centered tetrapyridyl ligand and ancillary carboxylate ligands that enables independent change in (i) charge, (ii) coordination environment of the redox-active center(s), and (iii) electronic coupling strength between redox centers. Variable-temperature electrochemical analysis of the series reveals the temperature coefficient for Fe-based redox couples to be highly dependent on the coordination environment of the redox-active center(s), with Fe centers in a pseudo-octahedral [FeN<sub>3</sub>O<sub>3</sub>] coordination environment affording a 2-fold greater temperature coefficient for the Fe<sup>III</sup>/Fe<sup>II</sup> redox couple than those in ancillary ferrocenyl groups. In contrast, identical temperature coefficients for the Fe<sup>III</sup>/Fe<sup>II</sup> redox event in Fe<sub>2</sub> and FeZn complexes establish electronic coupling strength to have a minimal impact on the temperature dependence of the Fe-based redox couple. Taken together, these results provide important insights for the design of molecular compounds with target redox properties, and they provide the first examination of how electronic coupling influences the temperature dependence of the redox potential and the associated redox entropy in molecular compounds.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 5","pages":"741-753"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12051193/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144057622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-17eCollection Date: 2025-06-05DOI: 10.1021/acselectrochem.4c00227
Samuel Groysman, Yisi Chen, Adaly Garcia, Christian Martinez, Kevin Diego-Perez, Miriam Benavides, Yi Chen, Zijian Wan, Shaopeng Wang, Rujia Liu, Dengchao Wang, Chong Liu, Yixian Wang
{"title":"Sensitive Imaging of Electroactive Species in Plasmonic Electrochemical Microscopy Enabled by Nanoconfinement.","authors":"Samuel Groysman, Yisi Chen, Adaly Garcia, Christian Martinez, Kevin Diego-Perez, Miriam Benavides, Yi Chen, Zijian Wan, Shaopeng Wang, Rujia Liu, Dengchao Wang, Chong Liu, Yixian Wang","doi":"10.1021/acselectrochem.4c00227","DOIUrl":"10.1021/acselectrochem.4c00227","url":null,"abstract":"<p><p>Spatially resolved sensing is a burgeoning area of electrochemistry that, in contrast to traditional electrochemical techniques, allows for the analysis of heterogeneous systems such as neurotransmitter release from cells. Of these techniques, optical microscopy methods are valued for real-time high throughput sensing. However, improving the sensitivity of many optical techniques remains a challenge. Here, we modify the gold (Au) electrode of the standard plasmonic electrochemical microscopy (PEM) setup with a mesoporous silica film (MSF) to achieve sensitive imaging of the electroactive species. Sensitivity enhancement occurs via species nanoconfinement from the attraction of ions to the negatively charged silica films, thereby increasing the local concentration change and magnifying the PEM signal. The performance of Au-MSF electrodes in the PEM setup was investigated using 1,1'-ferrocenedimethanol, whose oxidized form carries a positive charge. Results revealed enhancement of the sensing signal, with up to 37-fold improvement in the detection limit and up to 23 times improvement in the sensitivity. Importantly, Au-MSF electrodes allowed for the quantification of detected concentrations, in contrast to Au electrodes, for which R<sup>2</sup> values were unacceptably low. Furthermore, Au-MSF electrodes also showed increased sensitivity for dopamine detection compared to Au electrodes and were able to visualize localized dopamine release, showing this setup's great promise for biological applications, such as real-time imaging of the neurotransmitter release.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 6","pages":"974-986"},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147111/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-07eCollection Date: 2025-06-05DOI: 10.1021/acselectrochem.4c00212
Lifu Tan, Byung-Man Kim, Kohei Shimokawa, Su Jin Heo, Arvind Pujari, Michael De Volder
{"title":"Distinguishing between Photothermal and Photoelectric Effects in Li-Ion Batteries.","authors":"Lifu Tan, Byung-Man Kim, Kohei Shimokawa, Su Jin Heo, Arvind Pujari, Michael De Volder","doi":"10.1021/acselectrochem.4c00212","DOIUrl":"10.1021/acselectrochem.4c00212","url":null,"abstract":"<p><p>Over the past decades, photo-enhanced batteries where light is used to improve the rate performance or recharge batteries have received increased attention in the academic community. However, the underlying mechanisms that contribute to performance enhancement in several photo-enhanced batteries are still under debate. For instance, photothermal effects, resulting from light absorption and subsequent conversion to heat through non-radiative relaxation, and photo-induced charge transfer, involving the generation and separation of electron-hole pairs under the illumination resulting in charge carrier transport, can be challenging to disentangle. This study aims to distinguish between the photothermal and photo-induced charge transfer in TiO<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> as model systems because of their photoactivity and ability to store Li-ions. Using ultraviolet photoelectron spectroscopy (UPS) and UV-vis spectroscopy, we measure the band positions of these materials, and by a combination of different electrochemical processes, we demonstrate the transition from photothermal dominated to photoelectric effects in these materials. These results further illustrate the fact that different processes take place in photo-batteries, and this work provides a workflow to investigate these complex interactions.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 6","pages":"921-927"},"PeriodicalIF":0.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147141/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-02-07eCollection Date: 2025-06-05DOI: 10.1021/acselectrochem.4c00207
Melissa E Kreider, Ambar R Maldonado Santos, Arielle L Clauser, Matthew E Sweers, Leiming Hu, Emily K Volk, Ai-Lin Chan, Joshua D Sugar, Shaun M Alia
{"title":"Porous Transport Layers for Anion Exchange Membrane Water Electrolysis: The Impact of Morphology and Composition.","authors":"Melissa E Kreider, Ambar R Maldonado Santos, Arielle L Clauser, Matthew E Sweers, Leiming Hu, Emily K Volk, Ai-Lin Chan, Joshua D Sugar, Shaun M Alia","doi":"10.1021/acselectrochem.4c00207","DOIUrl":"10.1021/acselectrochem.4c00207","url":null,"abstract":"<p><p>Anion exchange membrane water electrolysis (AEMWE) is an emerging technology for the low-cost production of hydrogen. However, the efficiency and durability of AEMWE devices is currently insufficient to compete with other low-temperature electrolysis technologies. The porous transport layer (PTL) is a critical cell component that remains relatively unoptimized for AEMWE. In this study, we demonstrate that device performance is significantly affected by the morphology and composition of the PTL. For Ni fiber-based PTLs with a ∼2 μm Co<sub>3</sub>O<sub>4</sub> oxygen evolution reaction catalyst layer, decreasing the pore size and porosity resulted in a 20% increase in current density at 2 V in 1 M KOH supporting electrolyte. Alloy PTLs with even lower porosity had a higher performance; in particular, the stainless steel PTL gave an 80% increase in current density relative to Ni. Without Co<sub>3</sub>O<sub>4</sub>, the alloy PTLs still demonstrated high activity, indicating that the PTL material was catalytically active. However, characterization of the electrode and electrolyte after testing indicated that the alloy PTLs also underwent restructuring and corrosion processes that may limit long-term stability. This study demonstrates that the design of PTLs with improved morphology and composition is an important area of focus to achieve AEMWE performance targets.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 6","pages":"897-909"},"PeriodicalIF":0.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147155/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144268350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ACS electrochemistryPub Date : 2025-01-17eCollection Date: 2025-05-01DOI: 10.1021/acselectrochem.4c00156
Karam Yassin, Rinat Attias, Yoed Tsur, Dario R Dekel
{"title":"Identifying and Quantifying Loss Sources in Anion-Exchange Membrane Water Electrolyzers.","authors":"Karam Yassin, Rinat Attias, Yoed Tsur, Dario R Dekel","doi":"10.1021/acselectrochem.4c00156","DOIUrl":"https://doi.org/10.1021/acselectrochem.4c00156","url":null,"abstract":"<p><p>Anion-exchange membrane (AEM) water electrolyzers (AEMWEs) have gained significant attention for their ability to utilize precious-metal-free catalysts and environmentally friendly fluorine-free hydrocarbon polymeric membranes. In this study, we identify and quantify the sources of performance losses in <i>operando</i> AEMWEs using an innovative approach based on electrochemical impedance spectroscopy and MATLAB-based impedance spectroscopy genetic programming. Using this approach, we move beyond conventional equivalent circuit models to develop a proper and analytical model of the distribution function of relaxation times (DFRT), enabling a deeper analysis of Faradaic and non-Faradaic processes. We apply this framework to isolate the critical processes-ohmic, ionic transport, charge transfer, and mass transfer-across various conditions, including KOH concentration, dry cathode operation mode with different anode electrolytes (KOH, K<sub>2</sub>CO<sub>3</sub>, and pure water), cell temperature, and membrane type. Our results indicate a considerable performance reduction as the KOH concentration in the anode decreases, primarily due to the relatively high ionic transport resistance. Our observations show that the performance of dry cathode operation with KOH in the anode yields a comparable performance to dual-side electrolyte feeding due to sufficient water back-diffusion from the anode, which efficiently maintains cathode hydration. Conversely, using pure water as an electrolyte in the anode with a dry cathode significantly increases cell resistances and compromises ionic transport, underscoring the urgent need for highly conductive ionomeric materials and strategies. These insights indicate that using DFRT to evaluate the AEMWE operation by separating and associating the electrochemical phenomena could simplify system design while enabling more efficient generation of dry, pure hydrogen and advancing the technology toward commercial application.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 5","pages":"655-666"},"PeriodicalIF":0.0,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12051194/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144002154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}