Activating Nickel-Molybdenum Electrocatalyst Via Copper-Element Modification Toward 1 A cm−2 Hydrogen Evolution in Non-Extreme pH Carbonate Buffer Electrolyte

• DOI: 10.1149/ma2023-01372130mtgabs
• Publication Date: 2023-09-19T23:03:55Z
• Authors: Takeshi Nishimoto; Keisuke Obata; Kazuhiro Takanabe
• Keywords: Oxygen evolution; Electrolysis of water; Alkaline water electrolysis

Water electrolysis driven by renewable electricity produces green hydrogen, which will play a pivotal role in realizing sustainable society. However, the production cost of hydrogen is currently $5.3/kg, nearly four times higher than $1.4/kg grey [1] necessitates reduction toward its large-scale deployment. While reducing electrolyzer one key interventions, [2] extremely acidic or alkaline conditions commercialized electrolyzers require expensive corrosion-tolerant materials as components, hinders further cost. In this sense, non-extreme pH water can be innovative technology because milder those potentially enable use cheap and abundant (such Fe stainless steel) components frame bipolar plate), [3] reduce and, end, hydrogen. Non-extreme was reported to suffer inferior performance compared extreme conditions. [4] our previous study using nickel iron-based anode potassium carbonate buffer solution at 10.5 achieved high oxygen evolution reaction (OER) performances comparable highly OER, [5] should followed development effective cathode for (HER) realize efficient electrolyzer. The present reports on discovery molybdenum-based electrocatalysts that efficiently catalyze HER electrolyte 10.5. First all, visibly flat films (Ni), molybdenum oxide (MoO x ), (NiMoO ) were prepared cathodic electrodeposition rotating disk electrodes. Their electrocatalytic testing revealed that, conditions, coexistence Ni Mo required achieve catalytic activity even K-carbonate Subsequently, variety transition metal elements (manganese, cobalt, copper, tungsten) introduced into NiMoO via co-electrodeposition onto foam substrate enhance performance. Among developed electrodes, modified with copper element (Cu)) best 1 A cm −2 an overpotential ca. 0.2 V, previously (Figure 1). Our characterization Cu addition made surface structure rougher led largest double-layer capacitance, both indicate enlarged active area. Besides, presence decreased apparent Tafel slope, suggesting tailored nature site, consistent shift peaks ex situ X-ray photoelectron spectroscopy (XPS) analysis. Finally, combined carefully selected polyether sulfone (PES) diaphragm, overall cell elevated 3.0 mol kg −1 353 K. resultant including series resistance voltage merely 2.0 competitive top-class commercial electrolyzers. These findings demonstrate potential electrochemical industrial applications. Reference “Finding sea green” , EDISON, 2021 . M. Chatenet, et al., Chem. Soc. Rev. 2022 51 4583. Pourbaix, “Atlas Electrochemical Equilibria Aqueous solutions”, 1974 T. Naito, ChemSusChem 8 e202102294. Nishimoto, e202201808. Figure