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Aleksey E. Kuznetsov

Bio: Aleksey E. Kuznetsov is an academic researcher from Federico Santa María Technical University. The author has contributed to research in topics: Chemistry & Aromaticity. The author has an hindex of 23, co-authored 77 publications receiving 3598 citations. Previous affiliations of Aleksey E. Kuznetsov include Utah State University & Federal University of São Carlos.


Papers
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Journal ArticleDOI
16 Apr 2010-Science
TL;DR: Extensive spectroscopic, electrochemical, and inhibition studies firmly indicate that [Co4(H2O)2(PW9O34)2]10– is stable under catalytic turnover conditions: Neither hydrated cobalt ions nor cobalt hydroxide/oxide particles form in situ.
Abstract: Traditional homogeneous water oxidation catalysts are plagued by instability under the reaction conditions. We report that the complex [Co4(H2O)2(PW9O34)2]10-, comprising a Co4O4 core stabilized by oxidatively resistant polytungstate ligands, is a hydrolytically and oxidatively stable homogeneous water oxidation catalyst that self-assembles in water from salts of earth-abundant elements (Co, W, and P). With [Ru(bpy)3]3+ (bpy is 2,2'-bipyridine) as the oxidant, we observe catalytic turnover frequencies for O2 production > or = 5 s(-1) at pH = 8. The rate's pH sensitivity reflects the pH dependence of the four-electron O2-H2O couple. Extensive spectroscopic, electrochemical, and inhibition studies firmly indicate that [Co4(H2O)2(PW9O34)2]10- is stable under catalytic turnover conditions: Neither hydrated cobalt ions nor cobalt hydroxide/oxide particles form in situ.

1,300 citations

Journal ArticleDOI
02 Feb 2001-Science
TL;DR: Ab initio studies indicate that Al4(2-) exhibits characteristics of aromaticity with two delocalized pi electrons and a square planar structure and maintains its structural and electronic features in all the MAl4- complexes.
Abstract: Aromaticity is a concept invented to account for the unusual stability of an important class of organic molecules: the aromatic compounds. Here we report experimental and theoretical evidence of aromaticity in all-metal systems. A series of bimetallic clusters with chemical composition MAl4– (M = Li, Na, or Cu), was created and studied with photoelectron spectroscopy and ab initio calculations. All the MAl4– species possess a pyramidal structure containing an M+ cation interacting with a square Al42– unit. Ab initio studies indicate that Al42– exhibits characteristics of aromaticity with two delocalized π electrons (thus following the 4n + 2 electron counting rule) and a square planar structure and maintains its structural and electronic features in all the MAl4– complexes. These findings expand the aromaticity concept into the arena of all-metal species.

560 citations

Journal ArticleDOI
25 Apr 2003-Science
TL;DR: Experimental and theoretical characterization of antiaromaticity in an all-metal system, Li3Al4–, produced by laser vaporization and studied with the use of photoelectron spectroscopy and ab initio calculations reveal a rectangular Al44– tetraanion stabilized by the three Li+ ions in a capped octahedral arrangement.
Abstract: We report the experimental and theoretical characterization of antiaromaticity in an all-metal system, Li3Al4–, which we produced by laser vaporization and studied with the use of photoelectron spectroscopy and ab initio calculations. The most stable structure of Li3Al4– found theoretically contained a rectangular Al44– tetraanion stabilized by the three Li+ ions in a capped octahedral arrangement. Molecular orbital analyses reveal that the rectangular Al44– tetraanion has four π electrons, consistent with the 4n Huckel rule for antiaromaticity.

211 citations

Journal ArticleDOI
TL;DR: It is shown that a recently synthesized Ga4-organometallic compound also contains an aromatic -Ga4(2-)- unit, analogous to the gaseous clusters.
Abstract: We investigated the electronic structure and chemical bonding of two bimetallic clusters NaGa4- and NaIn4- Photoelectron spectra of the anions were obtained and compared with ab initio calculations We found that the ground state of the two anions contains a square planar dianion interacting with a Na+ cation The Ga42- and In42- dianions both possess two delocalized π electrons and are considered to be aromatic, similar to that recently found in Al42- Using calculations for a model compound, we showed that a recently synthesized Ga4−organometallic compound also contains an aromatic −Ga42-− unit, analogous to the gaseous clusters

207 citations

Journal ArticleDOI
TL;DR: In this paper, a white solid was removed in vacuo, leaving a white, X-ray quality crystals (0.86 g, 87% yield) precipitated from solution, over 24 h.
Abstract: 1: [(Cp*2 ZrH3Li)3] (0.1 g, 0.27 mmol) was dissolved in THF (3 mL), PH2CH2CH2PH2 (1.0 g, 10.87 mmol) was added dropwise to the stirred, colorless solution which became green, then aquamarine, and finally blue, over a period of 30 min. The reaction was stirred for 72 h, until it became colorless. Solvent was removed in vacuo, leaving a white solid which was dissolved in hexane, filtered, and placed in a freezer (y35 8C). Colorless, X-ray quality crystals (0.86 g, 87% yield) precipitated from solution, over 24 h. 1H NMR (C6D6): dˆ 3.65 (dt, 2H, 1JP,Hˆ 330, 3JH,Hˆ 10 Hz), 2.43 (m, 2H), 1.87 (m, 2H), 1.14 (m, 2H), 0.74 (m, 2H); 13C{1H} NMR (C6D6): dˆ 38.36, 30.66; 31P NMR (C6D6): dˆy22.5 (P1: JP1,P1ˆy237, JP1,P0ˆy186, 2JP1,P0ˆ 20 Hz), y65.4 (P0: 1JP1,P1ˆy237, 1JP1,P0ˆy186, 2JP1,P0ˆ 20 Hz); elemental analysis (%) calcd for P4C4H10: C 26.39, H 5.54; found: C 26.18, H 5.42.

146 citations


Cited by
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Journal ArticleDOI
TL;DR: A comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals, including a brief introduction to nucleation and growth within the context of metal Nanocrystal synthesis, followed by a discussion of the possible shapes that aMetal nanocrystal might take under different conditions.
Abstract: Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

4,927 citations

Journal ArticleDOI
TL;DR: The Scope of Review: Large-Scale Centralized Energy Storage, Chemical Energy Storage: Solar Fuels, and Capacitors 6486 5.1.2.
Abstract: 1. Setting the Scope of the Challenge 6474 1.1. The Need for Solar Energy Supply and Storage 6474 1.2. An Imperative for Discovery Research 6477 1.3. Scope of Review 6478 2. Large-Scale Centralized Energy Storage 6478 2.1. Pumped Hydroelectric Energy Storage (PHES) 6479 2.2. Compressed Air Energy Storage (CAES) 6480 3. Smaller Scale Grid and Distributed Energy Storage 6481 3.1. Flywheel Energy Storage (FES) 6481 3.2. Superconducting Magnetic Energy Storage 6482 4. Chemical Energy Storage: Electrochemical 6482 4.1. Batteries 6482 4.1.1. Lead-Acid Batteries 6483 4.1.2. Alkaline Batteries 6484 4.1.3. Lithium-Ion Batteries 6484 4.1.4. High-Temperature Sodium Batteries 6484 4.1.5. Liquid Flow Batteries 6485 4.1.6. Metal-Air Batteries 6485 4.2. Capacitors 6485 5. Chemical Energy Storage: Solar Fuels 6486 5.1. Solar Fuels in Nature 6486 5.2. Artificial Photosynthesis and General Considerations of Water Splitting 6486

2,570 citations

Journal ArticleDOI
TL;DR: The current state of research on nanoscale-enhanced photoelectrodes and photocatalysts for the water splitting reaction with special emphasis of Fe(2)O(3) with an outlook on the challenges in solar fuel generation with nanoscales inorganic materials is reviewed.
Abstract: The increasing human need for clean and renewable energy has stimulated research in artificial photosynthesis, and in particular water photoelectrolysis as a pathway to hydrogen fuel. Nanostructured devices are widely regarded as an opportunity to improve efficiency and lower costs, but as a detailed analysis shows, they also have considerably disadvantages. This article reviews the current state of research on nanoscale-enhanced photoelectrodes and photocatalysts for the water splitting reaction. The focus is on transition metal oxides with special emphasis of Fe2O3, but nitrides and chalcogenides, and main group element compounds, including carbon nitride and silicon, are also covered. The effects of nanostructuring on carrier generation and collection, multiple exciton generation, and quantum confinement are also discussed, as well as implications of particle size on surface recombination, on the size of space charge layers and on the possibility of controlling nanostructure energetics via potential determining ions. After a summary of electrocatalytic and plasmonic nanostructures, the review concludes with an outlook on the challenges in solar fuel generation with nanoscale inorganic materials.

1,779 citations

Journal ArticleDOI
15 Apr 2016-Science
TL;DR: A room-temperature synthesis to produce gelled oxyhydroxides materials with an atomically homogeneous metal distribution that exhibit the lowest overpotential reported at 10 milliamperes per square centimeter in alkaline electrolyte and shows no evidence of degradation after more than 500 hours of operation.
Abstract: Earth-abundant first-row (3d) transition metal-based catalysts have been developed for the oxygen-evolution reaction (OER); however, they operate at overpotentials substantially above thermodynamic requirements. Density functional theory suggested that non-3d high-valency metals such as tungsten can modulate 3d metal oxides, providing near-optimal adsorption energies for OER intermediates. We developed a room-temperature synthesis to produce gelled oxyhydroxides materials with an atomically homogeneous metal distribution. These gelled FeCoW oxyhydroxides exhibit the lowest overpotential (191 millivolts) reported at 10 milliamperes per square centimeter in alkaline electrolyte. The catalyst shows no evidence of degradation after more than 500 hours of operation. X-ray absorption and computational studies reveal a synergistic interplay between tungsten, iron, and cobalt in producing a favorable local coordination environment and electronic structure that enhance the energetics for OER.

1,777 citations

Journal ArticleDOI
TL;DR: In this paper, a vision for a future sustainable hydrogen fuel community based on artificial photosynthesis is outlined and current progress towards artificial photosynthetic devices is reviewed, with particular focus on visible light active nanostructures.
Abstract: Hydrogen from solar-driven water splitting has the potential to provide clean energy. Current progress towards artificial photosynthetic devices is reviewed, with particular focus on visible light active nanostructures. A vision for a future sustainable hydrogen fuel community based on artificial photosynthesis is outlined.

1,703 citations