Rapid Synthesis and Correlative Measurements of Electrocatalytic Nickel/Iron Oxide Nanoparticles.

Title Rapid Synthesis and Correlative Measurements of Electrocatalytic Nickel/Iron Oxide Nanoparticles.
Authors K.M. Jeerage; S.L. Candelaria; S.M. Stavis
Journal Sci Rep
DOI 10.1038/s41598-018-22609-x
Abstract

Electrocatalytic core-shell nanoparticles, such as nickel/iron oxides for the oxygen evolution reaction (OER) in alkaline electrolytes, require rapid synthesis and measurement for practical use. To meet this challenge, we investigated a novel process of adding Ni(II) species to Fe nanoparticles immediately after synthesis, which we expected to yield Ni-rich shells around Fe-rich cores. Cyclic voltammetry showed that the overpotential decreased as the molar ratio of Ni to Fe in the synthesis vessel increased from 0.2?mol Ni:1?mol Fe to 1.5?mol Ni:1?mol Fe, consistent with an increase of Ni composition. Unexpectedly, the overpotential increased abruptly at 2.0?mol Ni:1?mol Fe. X-ray photoelectron spectroscopy revealed that this synthesis ratio resulted in less Ni at the nanoparticle surfaces than lower synthesis ratios. These results demonstrate the sensitivity of rapid electrochemical measurements to surface composition, and the limits of Ni(II) adsorption and reduction to rapidly form Ni-rich shells around Fe-rich cores. Cyclic voltammetry also showed that the onset of the methanol oxidation reaction (MOR) correlates with the oxidation of Ni(OH)to NiOOH. Therefore, tuning materials to improve performance as OER catalysts also improves their performance as MOR catalysts.

Citation K.M. Jeerage; S.L. Candelaria; S.M. Stavis.Rapid Synthesis and Correlative Measurements of Electrocatalytic Nickel/Iron Oxide Nanoparticles.. Sci Rep. 2018;8(1):4584. doi:10.1038/s41598-018-22609-x

Related Elements

Iron

See more Iron products. Iron (atomic symbol: Fe, atomic number: 26) is a Block D, Group 8, Period 4 element with an atomic weight of 55.845. The number of electrons in each of Iron's shells is 2, 8, 14, 2 and its electron configuration is [Ar] 3d6 4s2. Iron Bohr ModelThe iron atom has a radius of 126 pm and a Van der Waals radius of 194 pm. Iron was discovered by humans before 5000 BC. In its elemental form, iron has a lustrous grayish metallic appearance. Iron is the fourth most common element in the Earth's crust and the most common element by mass forming the earth as a whole. Iron is rarely found as a free element, since it tends to oxidize easily; it is usually found in minerals such as magnetite, hematite, goethite, limonite, or siderite.Elemental Iron Though pure iron is typically soft, the addition of carbon creates the alloy known as steel, which is significantly stronger.

Nickel

See more Nickel products. Nickel (atomic symbol: Ni, atomic number: 28) is a Block D, Group 4, Period 4 element with an atomic weight of 58.6934. Nickel Bohr ModelThe number of electrons in each of nickel's shells is [2, 8, 16, 2] and its electron configuration is [Ar]3d8 4s2. Nickel was first discovered by Alex Constedt in 1751. The nickel atom has a radius of 124 pm and a Van der Waals radius of 184 pm. In its elemental form, nickel has a lustrous metallic silver appearance. Nickel is a hard and ductile transition metal that is considered corrosion-resistant because of its slow rate of oxidation. Elemental NickelIt is one of four elements that are ferromagnetic and is used in the production of various type of magnets for commercial use. Nickel is sometimes found free in nature but is more commonly found in ores. The bulk of mined nickel comes from laterite and magmatic sulfide ores. The name originates from the German word kupfernickel, which means "false copper" from the illusory copper color of the ore.

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