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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