(Digital Presentation) Nickel-Iron Electrocatalysts Modified with Group 11 Metals Achieving 1 A cm−2 of Oxygen Evolution in Buffered Near-Neutral pH Electrolyte

• DOI: 10.1149/ma2022-01361557mtgabs
• Publication Date: 2022-07-14T16:58:54Z
• Authors: Takeshi Nishimoto; Tatsuya Shinagawa; Kazuhiro Takanabe
• Keywords: Oxygen evolution; Overpotential

Electrocatalytic processes driven by the renewable electricity will play a pivotal role to achieve sustainable in our society, whereby thermodynamically stable chemicals are converted into value-added products or energy carriers. For instance, water electrolysis produces green hydrogen, and carbon dioxide yields commodity such as ethylene monoxide. [1] These commonly share an anodic half-reaction of oxygen evolution reaction (OER) that requires large overpotentials due its slow kinetics, leading significant loss overall efficiency. [2] This is particularly case at near-neutral pH, [3] which however likely desired condition for electrocatalytic CO 2 reduction lessened via carbonate formation prevails alkaline conditions. [4] Toward large-scale operation these technologies, it highly develop active, stable, earth-abundant metal based electrocatalyst catalyzes OER pH high current densities. The present study reports on discovery transition metal-based electrocatalysts efficiently catalyze buffer electrolyte pH. Firstly, variety electrodes were fabricated electro-deposition metals (manganese, iron, cobalt, copper) electrochemically activated Ni (ECA-Ni) substrates [5] with nanostructured surface. Their testing revealed iron oxide (Fe-O) modified ECA-Ni achieved density 100 mA cm −2 overpotential ca. 280 mV dense 1.5 mol kg −1 K-carbonate solution 353 K, whose was adjusted 10.5 298 K prior testing. level essential using Ni-Fe electrode. Subsequently, group 11 copper, silver, gold introduced Fe-O/ECA-Ni co-electrodeposition tailor nature active site improved OER. Remarkably, Fe-Cu-O/ECA-Ni Fe-Au-O/ECA-Ni catalyzed rate 1 A 330 mV, figure comparable those extremely conditions (Figure 1). Long-term on-off stability developed maintained performance. Our characterization double-layer capacitance indicated enlarged surface area Fe-Cu-O Fe-Au-O respect pristine Fe-O counterparts, partly contributed In addition, ex situ X-ray photoelectron spectroscopy absorption concurrently pointed presence Fe(III) species Fe-Cu-O/ECA-Ni, plausibly FeOOH. discovered densities, achieving performance conditions, given merits reduction. findings represent potentiality electrochemical system industrial scale, can help construct society. Reference S. Chu, A. Majumdar , Nature 2012 488 294. T. Reier, H. N. Nong, D. Teschner, R. Schlögl, P. Strasser, Adv. Energy Mater. 2017 7 1601275. Nishimoto, Shinagawa, Naito, K. Takanabe, ChemSusChem 2021 14 1554. J. Rabinowitz, M. W. Kanan, Nat. Commun. 2020 5231. T.-K. Ng, Angew. Chem. Int. Ed. 56 5061. Figure