The Electronic Structure of the Vanadyl Ion
About: This article is published in Inorganic Chemistry.The article was published on 1962-02-01. It has received 1293 citations till now. The article focuses on the topics: Vanadyl ion & Electronic structure.
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TL;DR: The emphasis of this review is on the origin of the electrocatalytic activity of nanostructured catalysts toward a series of key clean energy conversion reactions by correlating the apparent electrode performance with their intrinsic electrochemical properties.
Abstract: A fundamental change has been achieved in understanding surface electrochemistry due to the profound knowledge of the nature of electrocatalytic processes accumulated over the past several decades and to the recent technological advances in spectroscopy and high resolution imaging. Nowadays one can preferably design electrocatalysts based on the deep theoretical knowledge of electronic structures, via computer-guided engineering of the surface and (electro)chemical properties of materials, followed by the synthesis of practical materials with high performance for specific reactions. This review provides insights into both theoretical and experimental electrochemistry toward a better understanding of a series of key clean energy conversion reactions including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The emphasis of this review is on the origin of the electrocatalytic activity of nanostructured catalysts toward the aforementioned reactions by correlating the apparent electrode performance with their intrinsic electrochemical properties. Also, a rational design of electrocatalysts is proposed starting from the most fundamental aspects of the electronic structure engineering to a more practical level of nanotechnological fabrication.
3,918 citations
TL;DR: The high activity of BSCF was predicted from a design principle established by systematic examination of more than 10 transition metal oxides, which showed that the intrinsic OER activity exhibits a volcano-shaped dependence on the occupancy of the 3d electron with an eg symmetry of surface transition metal cations in an oxide.
Abstract: The efficiency of many energy storage technologies, such as rechargeable metal-air batteries and hydrogen production from water splitting, is limited by the slow kinetics of the oxygen evolution reaction (OER). We found that Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3–δ (BSCF) catalyzes the OER with intrinsic activity that is at least an order of magnitude higher than that of the state-of-the-art iridium oxide catalyst in alkaline media. The high activity of BSCF was predicted from a design principle established by systematic examination of more than 10 transition metal oxides, which showed that the intrinsic OER activity exhibits a volcano-shaped dependence on the occupancy of the 3d electron with an e g symmetry of surface transition metal cations in an oxide. The peak OER activity was predicted to be at an e g occupancy close to unity, with high covalency of transition metal–oxygen bonds.
3,876 citations
TL;DR: In this paper, the preparation of a colloidal colloidal by un procede sol gel is described, and a procedure for determination des proprietes electriques et electrochimiques is described.
2,040 citations
TL;DR: There have been many reviews and books on electron spin resonance (ESR) and several on transition metal ions as discussed by the authors, and many of these publications have been written by physicists or theoreticians and are very comprehensive.
Abstract: Publisher Summary There have been many reviews and books on electron spin resonance (ESR) and several on transition metal ions. Many of these publications have been written by physicists or theoreticians and are very comprehensive. This review is aimed at inorganic chemists, who have had no experience relating to electron spin resonance and who are becoming more and more likely either to use the technique or to need to appreciate the significance of the information available from the technique. The first part of the review gives an elementary account of the relevant theory. There are many good books for further reading for the inorganic chemist, who wishes to go deeper into the subject. The second part of the review is a comprehensive survey of the results of ESR studies on compounds of transition elements. Inevitably, there has had to be some selection of material, and the criteria for inclusion or rejection has been based upon the likely interest of an inorganic chemist might have in the species. This is particularly in the areas, where there is a lot of related work, e.g., the Mn2+ host-lattice data. In the case of copper dg complexes, there has been much duplication of work and papers devoted to the spectra of complexes where a minor substitutive change has been made to a bulky organic ligand.
481 citations
TL;DR: In this paper, the ESR spectra of vanadyl acetylacetonate and tetraphenylporphyrin have been studied in various liquid solvents and frozen glasses.
Abstract: The ESR spectra of vanadyl acetylacetonate and tetraphenylporphyrin have been studied in various liquid solvents and frozen glasses. The spectra have been analyzed and the components of the g tensor and of the vanadium hyperfine interaction tensors have been determined, and for the porphyrin the nitrogen extrahyperfine interaction tensor has been obtained. The unpaired electron is in the b2g* orbital. The extrahyperfine splitting is very isotropic which indicates that the b2g* orbital is localized on the vanadium in the porphyrin complex and the ``in‐plane π bonding'' is slight. An explanation of the origin of this extrahyperfine splitting is discussed in terms of configuration interaction. An analysis of the vanadium hyperfine interaction indicates that the b2g* orbital is localized on the vanadium in the acetylacetonate also, and that the Fermi contact interaction depends upon a number of excited configurations and varies from complex to complex and with change of solvent. The g‐tensor analysis suggests...
463 citations