Interestingly, an increase in electrical conductivity is observed for mixed oxides, with an optimum of (2.4 ± 0.2) × 102 S/cm at 64 at. % Co, outperforming both NiO and Co3O4 by several orders of magnitude. This change is accompanied by an increase in the Ni3+-to-Ni2+ ratio. The films exhibit a change in the crystallographic phase from the rock-salt to spinel structure for increasing cobalt at. %. The film composition is tuned using a supercycle approach built upon CoOx cycles with CoCp2 as a precursor and O2 plasma as a co-reactant and NiOx cycles with Ni(MeCp)2 as a precursor and O2 plasma as a co-reactant. In this work, we present the development of a plasma-enhanced atomic layer deposition (ALD) process of nickel cobalt oxide thin films (∼20 nm) with focus on the role of their chemical composition and crystal structure on the OER activity. The ideal chemical composition of these oxides remains debatable, with recent literature indicating that rock-salt NiCoO2 may exhibit similar OER activity as the traditional spinel NiCo2O4. Among these, nickel cobalt oxide thin films are considered promising candidates. However, application of AEMWE at industrial scale requires the development of oxygen evolution reaction (OER) electrocatalysts showing long-term stability under mild alkaline conditions. For definitions of ionic radius and further information, follow the hypertext link.Anion exchange membrane water electrolysis (AEMWE) is a promising technology for renewable electricity-driven water splitting toward hydrogen production. Further information is available in inorganic chemistry textbooks, usually at Level 1 or First Year University level. The terms low spin and high spin refer to the electronic configurations of particular geomtries of certain d-block metal ions. For electronic configurations, where it matters, the values given for octahedral species are low spin unless stated to be high spin. Size does depend upon geometry and environment. In this table, geometry refers to the arrangment of the ion's nearest neighbours. Hartree-Fock wave functions and radial expectation values: hydrogen to lawrencium, LA-3691, Los Alamos Scientific Laboratory, USA, 1968. The R max values for neutral gaseous element valence orbitals are abstracted from reference 1. Image showing periodicity of valence s-orbital radius for the chemical elements as size-coded balls on a periodic table grid. Table: valence shell orbital radii for cobalt. Two values are given here, one is based upon calculations and the other upon observation - follow the appropriate link for further details. The problem is its meaning, which is clearly very different in different sources and books. The term "atomic radius" is not particularly helpful although its use is widespread. Follow the appropriate hyperlinks for definitions of each radius type. The size of neutral atoms depends upon the way in which the measurement is made and the environment. All values of radii are given in picometres (pm). Follow the appropriate hyperlinks for literature references and definitions of each type of radius. There are several other ways ways to define radius for atoms and ions. It is not always easy to make sensible comparisons between the elements however as some bonds are quite short because of multiple bonding (for instance the O=O distance in O 2 is short because of the the double bond connecting the two atoms. One measure of size is the element-element distance within the element.
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