Electrosynthesis Faraday Discussion

12 - 14 July 2023, Edinburgh , United Kingdom

12-14 July 2023, Edinburgh and Online Electrosynthesis Faraday Discussion

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Book of Abstracts

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Electrochemical Science Advances Bimetallic PtCu/C Catalysts for Glycerol Assisted Hydrogen Evolution in Acidic Media Sonja D. Mürtz,* [a] Florian Musialek, [a] Norbert Pfänder, [b] and Regina Palkovits* [a, b]

Electrochemical Science Advances

Bimetallic PtCu/C Catalysts for Glycerol Assisted Hydrogen Evolution in Acidic Media Sonja D. Mürtz,* [a] Florian Musialek, [a] Norbert Pfänder, [b] and Regina Palkovits* [a, b]

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[a] S. D. Mürtz, F. Musialek, Prof. R. Palkovits Institute for Technical and Macromolecular Chemistry (ITMC), RWTH Aachen University Worringerweg 2, 52074 Aachen (Germany) E-mail: palkovits@itmc.rwth-aachen.de [b] Dr. N. Pfänder, Prof. R. Palkovits Max-Planck-Institute for Chemical Energy Conversion (MPI CEC) Stiftstraße 34–36, 45470 Mülheim an der Ruhr (Germany)

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03/2023

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2311 / 301204

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Introduction

Electrosynthesis Faraday Discussion is organised by the Faraday Community for Physical Chemistry of the Royal Society of Chemistry This book contains abstracts of the posters presented at Electrosynthesis Faraday Discussion. All abstracts are produced directly from typescripts supplied by authors. Copyright reserved. Oral presentations and discussions All delegates at the meeting, not just speakers, have the opportunity to make comments, ask questions, or present complementary or contradictory measurements and calculations during the discussion. If it is relevant to the topic, you may give a 5-minute presentation of your own work during the discussion. These remarks are published alongside the papers in the final volume and are fully citable. If you would like to present slides during the discussion, please let the session chair know and load them onto the computer in the break before the start of the session. Faraday Discussion volume Copies of the discussion volume will be distributed approximately 6 months after the meeting. To expedite this, it is essential that summaries of contributions to the discussion are received no later than Friday 21 st July 2023 for questions and comments and Friday 4 th August 2023 for responses. Posters Posters have been numbered consecutively. The poster session will take place on Wednesday 12 July 2023 after the main sessions have ended. The posters will be available to view throughout the discussion during all refreshment breaks. During the dedicated poster session, authors should stand with their poster to discuss their research with other attendees. Poster prize The Faraday Discussions poster prize will be awarded to the best student poster as judged by the committee. Networking sessions There will be regular breaks throughout the meeting for socialising, networking and continuing discussions started during the scientific sessions.

Invited Speakers

Scientific Committee

Toshio Fuchigami (Introductory lecturer) Tokyo Institute of Technology, Japan

Shelley Minteer (Chair) University of Utah, United States Song Lin Cornell University, United States

Kevin Moeller (Closing speaker) Washington University in St Louis, United States Victoria Flexer CONICET-Universidad Nacional de Jujuy, Argentina

Kevin Lam University of Greenwich, United Kingdom

Thomas Wirth Cardiff University, United Kingdom Lutz Ackermann University of Goettingen, Germany

Shinsuke Inagi Tokyo Institute of Technology, Japan

Robert Francke Universität Rostock, Germany

Richard Brown University of Southampton, United Kingdom

Dipannita Kalyani Merck, United States

Alexander Kuhn University of Bordeaux, France

Faraday Discussions Forum

www.rscweb.org/forums/fd/login.php

In order to record the discussion at the meeting, which forms part of the final published volume, your name and e-mail address will be stored in the Faraday Forum. This information is used for the collection of questions and responses communicated during each session. After each question or comment you will receive an e-mail which contains some keywords to remind you what you asked, and your password information for the forum. The e-mail is not a full record of your question. You need to complete your question in full on the forum . The deadline for completing questions and comments is Friday 21 July.

The question number in the e-mail keeps you a space on the forum. Use the forum to complete, review and expand on your question or comment. Figures and attachments can be uploaded to the forum. If you want to ask a question after the meeting, please e-mail faraday@rsc.org. Once we have received all questions and comments, responses will be invited by e-mail . These must also be completed on the forum . The deadline for completing responses is Friday 4 August. Please note that when using the Forum to submit a question or reply, your name and registered e-mail address will be visible to other delegates registered for this Faraday Discussions meeting. Key points: • The e-mail is not a full record of your comment/question. • All comments and responses must be completed in full on the forum Deadlines: Questions and comments Friday 21 July Responses Friday 4 August

With thanks to our Sponsors

Poster presentations

P01

Alkali metal cations as promoters of (non) Kolbe electrolysis: a systematic study of their effect on product selectivity Ashraf, Talal University of Twente, Netherlands Mediated Silane Oxidation: a practical and metal-free counter-electrode process for electrochemical reduction reactions Avanthay, Mickael University of Bristol, UK Screening and reaction monitoring with a high-throughput potentiostat Baker, Lane Texas A&M University, USA

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Electrosynthesis of homoquinone and oxygenated heterocycles in the reduction of 1,2-Naphthoquinone in the presence of phenacyl bromide

Batanero Hernán, M. Belén Universidad de Alcalá, Spain

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Reduction by oxidation: reduction of electron-deficient aryl halides by the electrochemically mediated oxidation of oxalate Beeler, Joshua University of Utah, USA The electroactive species of aliphatic aldehydes during their electrocatalytic oxidation at gold electrodes Bondue, Christoph Ruhr-University Bochum, Germany Investigation of CuPb electrodes for the electrocatalytic synthesis of glycine Broersen, Pim University of Amsterdam, The Netherlands Improved electrosynthesis of biomass derived furanic compounds via redox mediation design Carroll, Emily University of Utah, USA

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A reaction with potential: an electrosynthesis of 1,3,4-oxadiazoles from n-acyl hydrazones Chen, Luke University of Strathclyde/GSK, UK Development of an electrochemical benzylic c(sp3)-h amidation reaction and 3D-printed toolkit for ElectraSyn expansion Choi, Anthony University of Bristol, UK (Photo)electrochemical formate production from biomass by using copper oxide as a selective electrocatalyst Chuang, Ping-Chang National Cheng Kung University, Chinese Taipei Biomimetic mineralisation of conformal TiO 2 protection layers on nanostructured photoelectrodes for sustainable fuel production Chuang, Ping-Chang National Cheng Kung University, Chinese Taipei Developing an electrochemical assay for the directed evolution of enzymes for electrosynthesis Gerulskis, Rokas University of Utah, USA Electropolymerization of aromatic monomers driven by a streaming potential Iwai, Suguru Tokyo Institute of Technology, Japan Progress on the Development of an Electrochemically Regenerable Hydride Agent Karr, Dylan San Diego State University, USA

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Electrochemical characterization of Sav Hppd Az1 Kays, Luke University of Utah, USA Solution-based synthesis of earth-abundant materials for photoelectrochemical solar fuel production Lai, Yi-Hsuan National Cheng Kung University, Chinese Taipei

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Tuning carbon nanomaterials as conductive supports for hydrogenases and other biocatalysts Landis, Maya University of Oxford, UK Efficient electrocatalytic CO 2 reduction using a polyaniline|gold nanoparticle core-shell nanofiber modified electrode Lin, Chia-Yu National Cheng Kung University, Chinese Taipei Synthesis of substituted tetralins via electrochemical decarboxylative cycloalkylation Lunghi, Enrico Università degli Studi di Pavia, Italy Surveying the structural dependence of electrochemical properties and performance of verdazyl radicals in organic redox flow batteries Milner, Matthew University of Muenster, Germany Electrolyte induced cage effects for enantioselective electrosynthesis Nguyen, Zachary University of Utah, USA Parametrization of catalytic system for organic electrosynthesis by real- time mass spectrometry Nikolaienko, Pavlo Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Germany Synthesis of N+-Doped triphenylene derivatives by electrochemical intramolecular pyridination and their optoelectronic properties Ono, Yushi Tokyo Institute of Technology, Japan Dihydrolevoglucosenone-EtOH (Cyrene®-EtOH) mixture as solvent in electrochemical reduction of carbonyl compounds Ramos-Villaseñor, José Manuel Universidad Nacional Autónoma de México, Mexico Discovery and design of tri-metallic structure electrocatalysis for prompting c-c bond formation in the electrochemical reduction of CO 2 Rasul, Shahid Northumbria University, UK

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Turning essential oil into a degradable polymer by catalytic oxidation Seko, Tatsuya Yokohama National University, Japan Electrochemical C-N coupling reaction by π-extended haloarene mediator Shida, Naoki Yokohama National University, Japan Photoelectrochemistry for sustainable hydrogen generation and isotope separation Sokalu, Eniola University of Warwick, UK Electrochemical polymer reaction of Poly(3-hexylthiophene) via anodic C–H phosphonylation Taniguchi, Kohei Tokyo Institute of Technology, Japan Computational fluid dynamic modelling of electrochemical reactor for CO 2 conversion to ethylene Virdee, Ashween Heriot-Watt University, UK Merging electrocatalytic alcohol oxidation with C-N bond formation by electrifying metal-ligand cooperative catalysts von Wolff, Niklas CNRS, France Highly efficient gaseous fuel synthesis via co-electrolysis process Yamaguchi, Toshiaki Natinal Institute of Advanced Industrial Science and Technology (AIST), Japan Electrochemical reactor dictates site selectivity in N-heteroarene carboxylations Yu, Peng Eastern Institute for Advanced Study, China

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Alkali metal cations as promoters of (non) Kolbe electrolysis: a systematic study of their effect on product selectivity Talal Ashraf 2 , Bastian Mei 1,2 , Guido Mul 2 1 Industrial Chemistry Ruhr-University Bochum Universitätsstr, Germany, 2 University of Twente, Netherlands Carboxylic acids in biomass pyrolysis oil can be electrochemically transformed into alkanes and alcohols via Kolbe and Hofer Moest reaction, with selectivity dependent on factors such as electrode material, supporting electrolyte, pH and current densities 1,2 . Alkali metal cations in supporting electrolyte were considered inert spectators for Kolbe electrochemical oxidation 3 . However, our recent studies show that they can affect the oxidation currents and faradaic efficiency. Cations in the electrolyte solution (Li + <Na + <K + ~Cs + ) affect the product profile and electrochemical activity observed in conditions of oxygen evolution reaction (OER), Kolbe electrolysis and Hofer Moest reaction. Small cations interfere more strongly with the surface adsorbed oxygenates. To verify the effect of the cation during the transition from OER to Kolbe reaction, we used a rotating ring disc electrode (RRDE) to identify the inflection zone where OER begins to inhibit and changes in interfacial pH. OER was suppressed at 2.5V RHE with K + cations but not in the presence of Li + cations. References 1. F. J. Holzhäuser, J. B. Mensah and R. Palkovits, Green Chem., 2020, 22, 286–301. 2. C. Stang and F. Harnisch, ChemSusChem, 2016, 9, 50–60. 3. H. J. Schäfer, in Comprehensive Organic Synthesis, eds. B. M. Trost and I. Fleming, Pergamon, Oxford, 1991, pp. 633–658.

P01

Mediated Silane Oxidation: a practical and metal-free counter- electrode process for electrochemical reduction reactions Mickael Avanthay and Alastair J.J. Lennox University of Bristol, UK The ever-developing field of electro-organic synthetic chemistry aims to deliver transformations that are more efficient, safer and less environmentally impactful than their regular chemical-based counterparts 1 . However, every electrochemical transformation needs a counter-process happening at the opposite electrode. For oxidative reactions, proton reduction at the anode is the go-to counter-process since the formed hydrogen simply bubbles away, but there is no equivalent, broadly applicable counter-process for reduction reactions. Current approaches include the use of sacrificial anodes, various sacrificial chemical reductants or in many cases, it is simply ignored. While these may be satisfactory on some levels, the use of sacrificial metals is not ideal for sustainability and scalability reasons, and for the chemical reductants compatibility issues warrant the use of a divided cell 2 or limit how negative the potential can be applied on the cathode. 3,4 An ideal oxidative counter-process needs to be metal-free and produce soluble, reductively stable products. It should be compatible with flow chemistry and amenable to simple undivided setups such as regular Schlenk tubes or beakers. Herein we disclose an electrochemical silane oxidation which shows broad applicability as a counter-process: It was successfully applied to our recent report of a reductive hydrodefluorination of trifluoromethyl arenes 5 that previously required a divided cell, as well as other electrochemical transformations recently published by other groups that rely on sacrificial anodes. Overall, this new system for oxidative counter-processes has shown robustness in anhydrous and aqueous conditions. It is metal-free, generates no precipitate and relies on low-toxicity, stable and cheap reagents. It is a potential alternative to separators and sacrificial anodes, which is of particular interest for facilitating adaptation to flow electrochemistry and lowering the barrier of entry for electrochemistry newcomers.

References 1. Schäfer, H. J. Comptes Rendus Chim. 2011 , 14 (7–8), 745–765. 2. Wirtanen, T.; Rodrigo, E.; Waldvogel, S. R.. Adv. Synth. Catal. 2020 , 362 (11), 2088–2101. 3. Klein, M.; Waldvogel, S. R.. Angew. Chem. Int. Ed. 2022 , 61 (47). 4. Meyer, T. H.; Choi, I.; Tian, C.; Ackermann, L. Chem 2020 , 6 (10), 2484–2496. 5. Box, J. R.; Avanthay, M. E.; Poole, D. L.; Lennox, A. J. J. ACIE 2023 , 62 (12).

P02

Screening and reaction monitoring with a high-throughput potentiostat

Lane Baker 1 , Benjamin H. R. Gerroll 2 , Krista Kulesa 2 1 Texas A&M University, USA, 2 Indiana University, USA

Discovery and analysis with array-based measurements is an important approach in modern measurement science. For instance, arrays of biomolecules, such as nucleic acids or peptides, have proven key tools in genomics, proteomics, molecular biology and bioinformatics. Likewise, arrays of materials, such as ligands, nanoparticles, and metallic compositions, have found utility in the discovery of new catalysts.Signal detection/ transduction in array-based measurements has been dominated by optical methods, where fluorescence is especially adept. Array analysis by mass spectrometry has also contributed significant discoveries. Electrochemical arrays have also found application, however, to a lesser extent Electrochemical arrays often consist of a single type of electrode arrayed in series to take advantage of mass transport effects to the array. Parallel approaches where each electrode in an array can be operated at the same time with independent control of potential and signal collection have been much less common, owing largely to difficulties in instrumentation. To truly enable high-throughput electrochemistry, we believe full control over each electrode in an array should be enabled. Applications of a parallel high-throughput electrochemical array could have broad impact in diverse areas of science, including electroorganic synthesis,electrocatalyst discovery, fundamental nanoscience, and bioelectrochemical assays. Here, we describe an electrochemical platform, colloquially referred to as “Legion” toward the goal of developing high-throughput routes to parallel electrochemical arrays. General instrumental construction, performance benchmarks, and preliminary application in the areas of electrosynthesis are described.

P03

Electrosynthesis of homoquinone and oxygenated heterocycles in the reduction of 1,2-Naphthoquinone in the presence of phenacyl bromide M. Belén Batanero Hernán , Laura Pastor, Noemi Salardón, Sara Cembellin Universidad de Alcalá, Spain Cyclopropanes are privileged compound whose enhanced metabolic stability and conformational rigidity over unsubstituted methylene units offer distinct advantages to medicinal chemists [1] . Further, cyclopropanes are structural units of several bioactive natural products and pharmaceutically important compounds including many marketed drugs [2] . A series of new trans- and cis-benzoyl-homoquinones (cyclopropane-fused quinone systems) were stereoselectively prepared [3] in good yield by the electrochemical reduction of 1,4-quinones to the corresponding radical anions -that acted as electrogenerated bases (EGB)- in the presence of α-bromoacetophenones or α-bromo propiophenone in DMF/LiClO4 as SSE. When this reaction is performed with 1,2-naphthoquinone, the nature of products (Figure 1) and their yield depend on the experimental conditions. Rationalized mechanism proposals are suggested and discussed.

References 1. M. Watanabe, T. Kobayashi, T. Hirokawa, A. Yoshida, Y. Ito, S. Yamada, N. Orimoto, Y. Yamasaki, M. Arisawa, S. Shuto, Org. Biomol. Chem. 2012, 10, 736. 2. a) D. Y.-K Chen, R.H. Pouwer, J.-A. Richard, Chem. Soc. Rev. 2012, 41, 4631. b) S. J. Chawner, M.J. Cases-Thomas, J.A. Bull, Eur. J. Org. Chem. 2017, 5015, and references cited therein. 3. K. Hamrouni, F. Barba, M.L. Benkhoud, B. Batanero. Journal of Organic Chemistry, 2017, 82, 6778.

P04

Reduction by oxidation: reduction of electron-deficient aryl halides by the electrochemically mediated oxidation of oxalate Joshua Beeler, Henry S. White, Seyyedamirhossein Hosseini University of Utah, USA Hydrodehalogenation reactions are quintessential in the remediation of harmful environmental pollutants and have also been found to be useful as an intermediate step in organic synthesis. 1,2 However, hydrodehalogenation requires harsh reaction conditions owing to the large bond dissociation energies associated with the cleavage of C–X (X = Cl, Br) bonds (200–450 kJ/mol). 3 Electrochemical hydrodehalogenation, therefore, requires the application of large negative potentials or the use of transition-metal-based electrocatalysis. 4,5 In this work we introduce a new electrochemical method where the redox-mediated oxidation of oxalate is used to reduce aryl halides. Oxidizing oxalate by one-electron results in the liberation of the strongly reducing carbon dioxide radical anion (CO 2 ·– ), which can subsequently reduce electron-deficient aryl halides. 6 Known as “oxidative reduction”, this method represents the case where electrochemical oxidation gives rise to the reduction of a molecule in solution. Mechanistic aspects of hydrodehalogenation by oxidative reduction were examined using cyclic voltammetry, finite difference simulations, and the products obtained from bulk electrolysis. It is assumed that two equivalents of CO 2 ·– participate in the homogeneous reduction of the aryl halide to form the corresponding aryl anion, which is protonated by water to give a hydrogenated product. Thus far, the efficient and selective hydrodehalogenation of electron-deficient aryl halides (chlorides and bromides) has been carried out with high yield and selectivity. References 1. Kametani, T.; Noguchi, I.; Saito, K. Kaneda, S. Chem. Soc. C. 1969 , 2036–2038. 2. Mitoma, Y.; Nagashima, S.; Simon, C.; Simion, A.M.; Yamada, T.; Mimura, K.; Ishimoto, K.; Tashiro, M. Sci. Technol. 2001 , 35 , 4145–4148. 3. Guo, Y.; Yang, L.; Wang, Z. Water Research 2023 , 324 , 119810.Cheng, H.; Scott, K.; Christensen, P.A. Electrochem. Soc. 2003 , 150 , D17–D24.

4. Ke, J.; Wang, H.; Zhou, L.; Mou, C.; Zhang, J.; Pan, L.; Chi, Y.R. Eur. J. 2019 , 25 , 6911–6914. 5. Hendy, C.M.; Smith, G.C.; Xu, Z.; Lian, T. Jui, N.T. Am. Chem. Soc. 2021 , 143 , 8987–8992.

P05

The electroactive species of aliphatic aldehydes during their electrocatalytic oxidation at gold electrodes Christoph Bondue and Kristina Tschulik Ruhr-Universität Bochum, Germany In many cases the selective oxidation of an aldehyde functional group to a carboxylic acid is an essential step in deriving value-added compounds from biomass [1] . It would be beneficial to develop a process that can achieve this step electrochemically, because this would allow us to directly utilize renewable electricity and to eliminate kinetically sluggish oxygen evolution as a counter reaction to hydrogen evolution during water electrolysis. It is widely assumed that the diolate is the electrochemically active species of aldehyde oxidation [2] . The latter forms in equilibrium when the carbonyl functional group reacts with OH - . Typically, this equilibrium lies far on the side of the aldehyde. Hence, even at high pH values only a small fraction of the aldehyde resides as diolate in the electrolyte. It is, therefore, believed that electrochemical aldehyde oxidation proceeds only in very alkaline electrolytes with high current densities. However, these conditions also lead to the rapid degradation of the reactant via aldol condensation and to the deactivation of the electrode by the decomposition products. Here, I present a study on the electrochemical oxidation of aliphatic aldehydes at gold electrode, which is a model reaction for the electrochemical upgrading of biomass derived aldehydes. Employing the Rotating Disc Electrode technique, we find for gold electrodes that the current due to aldehyde oxidation reaches diffusion limitation even in electrolytes of pH 12. At this pH the equilibrium concertation of the diolate is too low to account for the high currents observed experimentally. Accordingly, not only the diolate, but also other aldehyde species that reside in the aqueous electrolyte must be electroactive as well. Accordingly, there is no need for high pH-values to achieve the electrochemical conversion of aldehydes. However, OH - is still a reactant during aldehyde oxidation: this is evident from the fact that the current due to aldehyde oxidation becomes diffusion limited in OH - when the aldehyde concentration is increased beyond a certain threshold value. However, high reaction rates can be achieved in buffered electrolytes of mild alkalinity, thus avoiding electrolyte decomposition of the reactant. Furthermore, using Differential Electrochemical Mass Spectrometry, we confirm [3] that electrochemical aldehyde oxidation proceeds via hydrogen evolution. That is, the formyl hydrogen is not released as protons after cleavage of the C-H bond with the carbonyl carbon but evolved as H 2 . Based on this observation we propose a reaction mechanism in which the gold surface acts as a heterogeneous electro-catalyst. References 1. Werpy, T, and Petersen, G. Top Value Added Chemicals from Biomass: Volume I -- Results of Screening for Potential Candidates from Sugars and Synthesis Gas. United States: N. p., 2004. Web. doi:10.2172/15008859. 2. W.J. Bover, P. Zuman, J. Electrochem. Soc. 122 (1975) 368–377. 3. N.A. Anastasijevic, H. Baltruschat, J. Heitbaum, Electrochimica Acta 38 (1993) 1067–1072.

P06

Investigation of CuPb electrodes for the electrocatalytic synthesis of glycine Pim Broersen, Amanda Garcia University of Amsterdam, The Netherlands In a continued scientific effort to combat climate change, electrochemistry is a promising approach as the ‘chemistry of the future’.1 Through battery technology, chemical storage of energy through hydrogen production or direct use of electrical energy for chemical transformations, green electricity can be used to limit fossil fuel consumption. Although many research publications focus on facilitating the hydrogen evolution reaction (HER),2 this reaction is also sometimes seen as unfavoured, if for example an electroreduction of organic molecules is performed in aqueous media, HER contributes to a loss in faradaic efficiency. The aim of the presented work is the valorisation of CO2 and nitrate through C–N bond formation with an electrocatalyst that limits HER. Investigations started from oxalic acid and hydroxylamine, products from the electrochemical reduction of CO2 and nitrate, to form glycine as the final product. Previous work has shown the suitability of heavy metals such as mercury, lead and cadmium to suppress HER.3 In our work we use underpotential deposition of lead on copper metal electrode to achieve a single monolayer coverage, thereby reducing the total amount of lead used for the catalyst synthesis. The synthesized catalyst showed a marked improvement in selectivity, achieving a faradaic efficiency for glycine of 48%, as compared to 10% for a copper catalyst. Upon further studying of the catalyst with SEM-EDX and XPS it was found that the lead monolayer does not remain well organized during catalysis, but forms nanoclusters. These nanoclusters are likely active in catalysis, whilst the copper support layer becomes a less capable HER catalyst due to surface doping of lead. This indicates that there is a multifaceted effect of lead underpotential deposition on copper to facilitate catalysis, through creating new catalytic sites and inhibiting HER on the copper surface through disturbing the lattice. References 1. Gulaboski, R. Electrochemistry in the twenty-first century—future trends and perspectives. J Solid State Electrochem2020, 24, 2081. https://doi.org/10.1007/s10008-020-04550-0 2. a: Shiva Kumar, S.; Himabindu, V. Hydrogen Production by PEM Water Electrolysis – A Review. Sci. Energy Technol. 2019, 2 (3), 442–454. https://doi.org/10.1016/J.MSET.2019.03.002. b: Han, W. B.; Kim, I. S.; Kim, M. J.; Cho, W. C.; Kim, S. K.; Joo, J. H.; Lee, Y. W.; Cho, Y.; Cho, H. S.; Kim, C. H. Directly Sputtered Nickel Electrodes for Alkaline Water Electrolysis. Electrochim. Acta 2021, 386, 138458. https://doi.org/10.1016/J. ELECTACTA.2021.138458. 3. Kim, J. E.; Jang, J. H.; Lee, K. M.; Balamurugan, M.; Jo, Y. I.; Lee, M. Y.; Choi, S.; Im, S. W.; Nam, K. T. Electrochemical Synthesis of Glycine from Oxalic Acid and Nitrate. Chemie - Int. Ed. 2021, 60 (40), 21943–21951. https://doi.org/10.1002/ ANIE.202108352.

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Improved electrosynthesis of biomass derived furanic compounds via redox mediation design Emily Carroll , Shelley Minteer University of Utah, USA Global industrialization has escalated the demand for energy while contributing to carbon emissions, global warming, and climate change. To avoid irreparable damage to the atmosphere and ecosystems on earth, there is an increasing urgency for renewable energy, electrofuels, and fine chemical production derived independently from fossil fuel resources (e.g., coal, crude oil, natural gas). Sustainable resources such as biomass have shown promise as a versatile and renewable feedstock and an alternative source for chemicals and energy derived from petroleum ( 1 ). Biomass refers to plant matter such as grasses, woods, and crop residues (corn stover, wheat straw, sugar cane), and it is the most abundantly available raw material for the production of biofuels (annual production of biomass exceeding 170 billion tons) ( 2 ). Several important transformations stem from the biomass-derived furan molecule 5-hydroxymethylfurfural (HMF) and its derivatives ( 1,3 ). A key transformation of HMF is oxidation into the high value-added product 2,5-furan dicarboxylic acid (FDCA). FDCA is a precursor for polymeric materials including polyethylene furandicarboxylate (PEF), a bio-based alternative to petroleum- derived polyethylene terephthalate (PET) ( 4 ). However, traditional methods for the catalytic conversion of furan molecules rely on noble metal catalysts, organic solvents, and high temperatures and pressures. Alternatively, electrochemistry offers a streamlined approach to the synthesis of furan derivatives by eliminating the need for extensive oxidizing reagents and harsh reaction conditions. Instead, an applied electric potential serves as thermodynamic driving force for catalysis at lower temperatures. Here, we explore the electrochemical transformation of a reduced furan derivative, 2,5-bis(hydroxymethyl)furan (BHMF) to the polymeric precursor FDCA via mediated electrocatalysis. Not only has mediated electrochemical oxidation yet to be demonstrated for BHMF transformations, but this reaction also has the merit of running in aqueous conditions. Utilizing a library of redox mediators, we identify the key molecular parameters necessary for catalyzing selective alcohol oxidation. Using both transient techniques (cyclic voltammetry) to study mechanism and preparative scale electrolysis to study selectivity, we aim to build a comprehensive and predictive picture of mediated furan transformations, an under-utilized strategy in the present literature. These studies represent an opportunity for advancement in commodity chemical production from biomass. References 1. Simoska, O.; Rhodes, Z.; Weliwatte, S.; Cabrera-Pardo, J. R.; Gaffney, E. M.; Lim, K.; Minteer, S. D. Advances in Electrochemical Modification Strategies of 5-Hydroxymethylfurfural. ChemSusChem 2021, 14 (7), 1674-1686. 2. Röper, H. Renewable Raw Materials in Europe- Industrial Utilisation of Starch and Sugar. Starch - Stärke 2002, 54 (3-4), 89-99. 3. Zakrzewska, M. E.; Bogel-Łukasik, E.; Bogel-Łukasik, R. Ionic Liquid-Mediated Formation of 5-Hydroxymethylfurfural—A Promising Biomass-Derived Building Block. Chemical Reviews 2011, 111 (2), 397-417. 4. Marshall, A.; Jiang, B.; Gauvin, R. M.; Thomas, C. M. 2,5-Furandicarboxylic Acid: An Intriguing Precursor for Monomer and Polymer Synthesis. In Molecules, 2022; Vol. 27.

P08

A reaction with potential: an electrosynthesis of 1,3,4-oxadiazoles from N-Acyl hydrazones Luke Chen 1,2 , James Thompson 1 and Craig Jamieson 2 1 GSK, UK and 2 University of Strathclyde/GSK, UK This work has established an electrochemical conversion of N -acyl hydrazones to synthesise 2,5-disubstituted 1,3,4-oxadiazoles. The 1,3,4-oxadiazole is a valuable heterocycle with useful medicinal properties. As a stable bioisostere of esters and amides, ubiquitous functional groups in many drugs and bioactive molecules, incorporating the underutilised oxadiazole enables the expansion and exploration of greater chemical space. 1 To highlight this, it is an important component of raltegravir, a top 10 selling anti-HIV drug in 2020. 2 Consequently, more efficient methods to access these heterocycles are required. Methodologies to synthesise 1,3,4-oxadiazole analogues have been reported in the literature, such as via oxidative or dehydrative cyclisation reactions. 3,4 However, they are often limited by poor atom economy and the need for highly reactive, toxic, or corrosive reagents. Herein is described an electrochemical oxidation which offers a green and attractive alternative. Stoichiometric use of conventional chemical oxidants, and their associated hazards, have been avoided to convert inexpensive and readily available starting materials into valuable products. Taking an indirect electrolysis approach, this strategy offers advantages to established protocols in that milder conditions can be employed to improve functional group compatibility. Extensive screening efforts have identified the hydrogen atom transfer (HAT) mediators, such as DABCO, as the optimum redox catalysts for the reaction. The rapid reaction optimisation was accomplished using the IKA ElectraSyn 2.0, enabling greater accessibility of electrochemistry for synthetic, organic chemists. The operationally simple methodology is also amenable to a one- pot procedure from hydrazone precursors, further simplifying the process. Tolerance for a broad range of relevant functional groups has been demonstrated, with moderate to good yields obtained. This has enabled access to a wide array of medicinally privileged structures which would be valuable additions to a screening collection or as a tool for medicinal chemists, such as for determining structure-activity relationships. Work is ongoing to further explore the substrate scope, harnessing the reactivity to functionalise a wider range of hydrazones. References 1. J. Boström, A. Hogner, A. Llinàs, E. Wellner, and A. T. Plowright, J. Med. Chem. , 2012, 55 , 1817–1830. 2. F. Caputo, S. Corbetta, O. Piccolo, and D. Vigo, Org. Process Res. Dev. , 2020, 24 , 1149–1156. 3. K. D. Patel, S. M. Prajapati, S. N. Panchal, and H. D. Patel, Synth. Commun. , 2014, 44 , 1859– 1875. 4. L. Green, K. Livingstone, S. Bertrand, S. Peace, and C. Jamieson, Chem. Eur. J. , 2020, 26 , 14866–14870.

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Development of an electrochemical benzylic C(sp3)-H amidation reaction and 3D-printed toolkit for electrasyn expansion Anthony Choi 1 , Oliver Goodrich 2 , Matthew Edwards 2 , Alexander P. Atkins 1 , Michael W. George 2 , David M. Heard 1 , Alastair J. J. Lennox* 1 1 University of Bristol, UK, 2 University of Nottingham, UK This poster will present work from two different projects! Amides are ubiquitous and important motifs found in many drugs and natural products. [1] Although, traditional methods are robust and reliable, the necessity to develop new methods towards the synthesis of amide bonds remains important to provide flexibility when designing novel synthetic routes. Electrochemistry has provided a sustainable and selective method towards the synthesis of amides via anodic oxidation, which has been successfully applied to Ritter-type amidation reactions. [2] However, there are major limitations of this reaction which are associated with the nitrile coupling partner – mainly the availability and quantity required. To overcome these problems the use of primary amides as an alternative nucleophilic coupling partner has several advantages, such as being more widely available. The work highlighted demonstrates the use of primary amides in a novel electrochemical process to synthesise a variety of amides, which can also be scaled-up successfully in flow.

Another area of research we have also developed within recent years is the use of 3D-printing technology to build electrochemical reaction platforms for use in electrosynthetic reaction discovery. [3] Often, bespoke reactors are developed in-house for a specific purpose or are commercially available, which can offer high reproducibility and replicability by using standardized components. To bridge this divide between customizability and replicability, we have developed the Open-ESyn, a suite of 3D-printed components compatible with the popular IKA ElectraSyn. The work presented will show the development and utility of these 3D-printed components in various electrochemical reactions.

References 1. J Biotechnol , 2016 , 235 , 32–46; J Med Chem , 2020 , 63 , 12290–12358. J Am Chem Soc , 1948 , 70 , 4045–4048; 2. J Am Chem Soc , 2021 , 143 , 8597–8602; 3. Synthesis , 2023 , doi.org/10.1055/a-1992-7066; 4. Nat Commun , 2022 , 13 , 4138. ChemElectroChem , 2021 , 8 , 11, 2070-2074.

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(Photo)electrochemical formate production from biomass by using copper oxide as a selective electrocatalyst Ping-Chang Chuang and Yi-Hsuan Lai National Cheng Kung University, Chinese Taipei Platform chemicals such as formic acid derived by (photo)electrochemical valorisation of biomass-derived intermediates is a sustainable process. We recently reported an inexpensive and Earth-abundant CuO synthesised by a scalable approach acts as an efficient electrocatalyst for the selective production of formate from biomass [1] . Significantly, the CuO electrocatalyst demonstrates a high faradaic efficiency of formate of 94.1 ± 1.5% at 1.5 V versus reversible hydrogen electrode from glucose oxidation. Detailed product analyses suggest that one glucose is oxidised to one formate and one pentose at the potentials positive than the flat band potential of CuO. In addition to the glucose, the electrolysis of cellulose and “real world” biomass waste was also investigated. Despite the low solubility of the raw biomass, a moderate faradaic efficiency of 41.4 ± 9.7% was observed when using waste rice straw as feedstock. Furthermore, CuO can act as a co-catalyst for the photoelectrochemical production of formate. The faradaic efficiency for formate production was enhanced to 97.3 ± 2.8% over a CuO- coated hematite photoanode. References 1. P.-C. Chuang and Y.-H. Lai. Selective production of formate over a CuO electrocatalyst by electrochemical and photoelectrochemical biomass valorisation. Catal. Sci. Technol. 2022,12, 6375-6383.

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Biomimetic mineralisation of conformal TiO 2 protection layers on nanostructured photoelectrodes for sustainable fuel production Ping-Chang Chuang and Yi-Hsuan Lai National Cheng Kung University, Chinese Taipei Photoelectrochemical synthesis provides an elegant way to produce sustainable fuels by combining light absorbers and electrolysers in a single device. However, most photoelectrodes with a narrow bandgap suffer from photocorrosion or chemical dissolution. The conformal coating of chemically stable materials, such as TiO 2 , by atomic layer deposition (ALD) is a universal strategy to enhance the stability of desired photoelectrodes. Nevertheless, ALD's arduous and expensive process limits its further application in scale-up. To address this problem, we reported an environmental-friendly and scalable route to deposit the conformal TiO 2 inspired by mineralisation. The protamine-mediated process can successfully synthesise conformal TiO 2 on nanostructured WO 3 (nanoWO 3 |TiO 2 ) and microstructured Cu 2 O (microCu 2 O|TiO 2 ) by facile soaking in the protamine and titanium precursor solution sequentially. Photoelectrochemical stability studies also show the current density of nanoWO 3 |TiO 2 modified with oxygen evolution catalyst remains nearly 100% of its original current density at 1.0 V versus reversible hydrogen electrode (vs RHE) in a neutral solution for 1 hour. At the counter part, the current density of microCu 2 O|TiO 2 modified with hydrogen evolution catalyst remains nearly two times higher than that of no TiO 2 modified one. This scalable and simple deposition process can be readily applied to other promising materials. References 1. Y. -H. Lai, Y.-J. Lai, C.-Y. Yen, and P. -C. Chuang, Sustain. Energy Fuels 4 (2020) 5005-5008. 2. Developing an electrochemical assay for the directed evolution of enzymes for electrosynthesis Gerulskis, Rokas 3. University of Utah, USA

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Developing an electrochemical assay for the directed evolution of enzymes for electrosynthesis Rokas Gerulskis, Dylan Boucher, Shelley Minteer University of Utah, USA Traditional high-throughput assays for enzyme directed evolution aim to detect mutant “hits”, high activity mutants, through semiquantitative spectrochemical methods. These assays typically employ a secondary catalyst or reagent which produces a colorimetric signal proportional to the product generated by the enzyme of interest, with the aim of screening hundreds of mutants for high activity in short order. These assays are not only laborious to optimize, but are extremely product-specific, offering little utility in the realm of substrate-scope determination. A similar kinetic method in the context of enzymatic electrochemistry is mediated electrocatalysis, wherein the redox of electron mediating species such as ferrocene, viologens, or quinones occurs in proximity of enzyme active sites proportional to enzymatic activity and is consequently independent of the specific redox reaction catalyzed by the enzyme. The rate of mediator turnover can then be quantified as a catalytic current thus providing a readout of enzymatic activity. Electrochemical literature has focused on precise quantification of electroenzymatic activity requiring laborious purification of target enzymes, while little attention has been directed to maximizing reaction throughput in the realm of mutant and substrate-scope screening. This work introduces preliminary investigations into a method to rapidly screen enzyme mutants and substrate specificity using a 96-well electrochemical cell.

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Electropolymerization of aromatic monomers driven by a streaming potential Suguru Iwai, Ikuyoshi Tomita, Shinsuke Inagi Tokyo Institute of Technology, Japan Bipolar electrodes (BPEs), which are driven by an external electric field with a low concentration of supporting electrolyte, are attracting more attention thanks to their unique features such as gradient potential distribution, synergy with electrophoresis, and so on [1] . In contrast to conventional electrolysis, which requires a large amount of supporting electrolyte, bipolar electrolysis can reduce the amount of supporting electrolyte. Therefore, bipolar electrochemistry is an environmentally friendly electrolysis system. We have achieved electrochemical fluorination using BPEs in a batch cell [2] and a flow cell [3] , reducing the amount of supporting electrolyte to 1/100 compared with conventional electrolysis (Figure 1(a)) . Recently, a novel pressure-driven BPE system has been demonstrated by Crooks et al., where the BPE is driven by a streaming potential ( E str ) [4] . E str is a potential difference between the inlet and the outlet of the microchannel as the low concentration electrolyte is pumped. In this context, we have developed an electrolytic system using BPEs without an external electric power supply [5] . Herein, we report the electropolymerization of aromatic monomers using the pressure-driven BPE ( Figure 1(b) ). First, the E str was measured with various electrolytes and channel materials. As a result, about 2.0 V of E str was observed by filling a microchannel with cotton and pumping the electrolyte of 0.5 mM Bu 4 NPF 6 /MeCN. This value of E str is sufficient for pyrrole electropolymerization. Then, we carried out the electropolymerization of pyrrole with this BPE device. During the pumping of the electrolyte containing pyrrole, the current associated with electrolysis was observed, indicating the progress of electropolymerization. In fact, polypyrrole was deposited on the upstream electrode, while there was no deposition on the downstream electrode. The cyclic voltammetry measurement supported the polypyrrole deposition. Therefore, we concluded that the electropolymerization proceeded with the upstream electrode as the anode and the downstream electrode as the cathode. More details of E str measurement and electropolymerization will be shown in the poster presentation.

References 1. N. Shida, Y. Zhou, S. Inagi, Acc. Chem. Res. , 2019 , 52 , 2598–2608. 2. K. Miyamoto, H. Nishiyama, I. Tomita, S. Inagi, ChemElectroChem , 2019 , 6 , 97–100. 3. H. Sakagami, H. Takenaka, S. Iwai, N. Shida, E. Villani, A. Gotou, T. Isogai, A. Yamauchi, Y. Kishikawa, T. Fuchigami, I. Tomita, S. Inagi, ChemElectroChem , 2022 , 9 , e202200084. 4. I. Dumitrescu, R. K. Anand, S. E. Fosdick, R. M. Crooks, J. Am. Chem. Soc. , 2011 , 133 , 4687–4689. 5. S. Iwai, T. Suzuki, H. Sakagami, K. Miyamoto, Z. Chen, M. Konishi, E. Villani, N. Shida, I. Tomita, S. Inagi, Commun. Chem. , 2022 , 5 , 66.

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Progress on the development of an electrochemically regenerable hydride agent Dylan Karr, Diane K. Smith San Diego State University, USA Hantzsch’s ester or amide is commonly used as a stoichiometric hydride transfer reagent in organic synthesis. The goal of this research is to see if Hantzsch’s ester or amide can be converted into an electrochemically- reversible hydride transfer mediator. The first step in achieving this is to realize the reversible 2 electron, 1 proton reduction of the corresponding pyridinium, 1, as shown below. Normally reduction of pyridiniums such as 1 are electrochemically irreversible due to the dimerization of the initially formed uncharged radical. We believe the key to avoid this pathway is to add a H-donor that can H-bond to the carbonyl O’s in such a way that an acidic H is properly positioned to H-bond to the radical, facilitating a second electron-transfer, proton-transfer step to generate the hydride donor. This poster will describe the results of our initial efforts to achieve reversibility in this system and additional hydride systems such as benzimidazoliums.

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Electrochemical characterization of Sav Hppd Az1 Luke Kays, Dylan Boucher, Julian Buchholz, Shelley Minteer University of Utah, USA

Directed evolution has been well documented as an efficient and powerful tool to engineer enzymes for specific functions, such as enzyme stability, or reprogramming an enzyme’s selectivity for a different substrate beyond its natural scope. Based on Darwinian evolution, directed evolution generates a series of genetic mutants via mutagenesis and screens them for a desired trait. The improved variant then acts as a starting point for the next cycle, and this continues until the desired trait is exhibited satisfactorily. Despite the synthetic achievements due to directed evolution it has not been paired with electrosynthetic methods. Such a pairing could provide access to novel and sustainable transformations with unprecedented and tunable selectivity. Sav HppD Az1 is a non heme iron enzyme designed via direct evolution to catalyze a C(sp 3 )-H azidation reaction. This process occurs through an iron-catalyzed radical transfer by an initial homogeneous N-F bond splitting. This N-F bond is required for the reaction to drive the necessary redox cycling of the iron active site. Direct electrochemical oxidation of the enzyme would eliminate the need for the N-F bond and greatly expand the scope of possible substrates. We investigated the possibility of adapting the reactivity of Sav HppD Az1 for an electrochemical system using less complex substrate structures. The enzyme was immobilized on the electrode surface using pyrene-functionalized hydrogels, which eliminates the need for a mediator. The redox features of the enzyme were examined via cyclic voltammetry and square-wave voltammetry in anaerobic conditions, with a distinct oxidation signal observed for the iron active site in the presence of azide, suggesting coordination into the active site. This methodology offers a way to investigate the reactivity of non-native enzymes and represents an electrosynthetic application of directed evolution.

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Solution ‐ based synthesis of Earth-abundant materials for photoelectrochemical solar fuel production Yi-Hsuan Lai National Cheng Kung University, Chinese Taipei Photoelectrochemical (PEC) solar fuel production has driven lots of attention in view of addressing climate change and the global energy crisis. Owing to the flexibility, scalability and cost-effectiveness, solution-based synthesis was applied in our research for synthesising effective photoelectrodes made of earth-abundant materials for solar fuel production. In the first study, a nanostructured Bi 4 O 5 I 2 electrode was prepared by a facile solvothermal process. The Bi 4 O 5 I 2 electrode can be readily converted to a CuBi 2 O 4 photocathode and the BiVO 4 photoanode by a solution conversion method followed by pairing the photoelectrodes in tandem for solar water splitting. [1] In the second work, a copper-incorporated BiVO 4 was synthesised by electrodeposition of BIOI on a conductive substrate followed by solution conversion and heat treatment. [2] The copper incorporation enhanced the efficiencies of charge separation and the interfacial charge transfer of BiVO 4 , which is evident from PEC analyses and electrochemical impedance spectroscopy. Recently, we also demonstrated that an exfoliated V 2 O 5 electrode can be prepared by a simple and facile solution-based synthesis. [3] The exfoliated V 2 O 5 was firstly prepared by a drop-casting process followed by heat treatments and liquid exfoliation. The exfoliated V 2 O 5 has significantly higher oxygen vacancies and better performance for PEC methanol oxidation than the non-exfoliated one. References

1. Y.-H. Lai, K.-C. Lin, C.-Y. Yen and B.-J. Jiang, Faraday Discuss., 2019, 215, 297. 2. T.-R. Ko, Y.-C. Chueh, Y.-H. Lai, C.-Y. Lin, J. Taiwan Inst. Chem. Eng., 2020, 111, 80. 3. T.-R. Ko, C.-Y. Lin, and Y.-H. Lai., Chem. Eng. J., 2022, 433, 133607.

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