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28 Mar 17:45

Mechanisms of Photogeneration and Relaxation of Excitons and Mobile Carriers in Anatase TiO2

by Maria C. Fravventura, Laurens D. A. Siebbeles and Tom J. Savenije

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The Journal of Physical Chemistry C
DOI: 10.1021/jp500132w
25 Mar 17:20

La0.8Sr0.2MnO3−δ Decorated with Ba0.5Sr0.5Co0.8Fe0.2O3−δ: A Bifunctional Surface for Oxygen Electrocatalysis with Enhanced Stability and Activity

by Marcel Risch, Kelsey A. Stoerzinger, Shingo Maruyama, Wesley T. Hong, Ichiro Takeuchi and Yang Shao-Horn

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Journal of the American Chemical Society
DOI: 10.1021/ja5009954
25 Mar 14:45

Tantalum-based semiconductors for solar water splitting

Chem. Soc. Rev., 2014, Advance Article
DOI: 10.1039/C3CS60438A, Review Article
Peng Zhang, Jijie Zhang, Jinlong Gong
This review describes the current status of the design, synthesis, and applications of tantalum-based semiconductors, including tantalum oxides, tantalates and tantalum (oxy)nitrides, for photocatalytic and photoelectrochemical water splitting.
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26 Mar 20:40

An Integrated Photoelectrochemical–Chemical Loop for Solar-Driven Overall Splitting of Hydrogen Sulfide

by Xu Zong, Jingfeng Han, Brian Seger, Hongjun Chen, Gaoqing (Max) Lu, Can Li, Lianzhou Wang

Abstract

Abundant and toxic hydrogen sulfide (H2S) from industry and nature has been traditionally considered a liability. However, it represents a potential resource if valuable H2 and elemental sulfur can be simultaneously extracted through a H2S splitting reaction. Herein a photochemical-chemical loop linked by redox couples such as Fe2+/Fe3+ and I/I3 for photoelectrochemical H2 production and H2S chemical absorption redox reactions are reported. Using functionalized Si as photoelectrodes, H2S was successfully split into elemental sulfur and H2 with high stability and selectivity under simulated solar light. This new conceptual design will not only provide a possible route for using solar energy to convert H2S into valuable resources, but also sheds light on some challenging photochemical reactions such as CH4 activation and CO2 reduction.

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Trash to Treasure: A photochemical–chemical loop for the overall H2S splitting was developed by integrating photoelectrochemical H2 production and H2S chemical absorption redox reactions with the link of a redox couple (Fe2+/Fe3+ or I/I3). Using functionalized silicon as photoelectrode, simultaneous extraction of H2 and elemental sulfur from H2S was successfully achieved (see picture).

28 Mar 13:20

Pigment–Acceptor–Catalyst Triads for Photochemical Hydrogen Evolution

by Kyoji Kitamoto, Ken Sakai

Abstract

In order to solve the problems of global warming and shortage of fossil fuels, researchers have been endeavoring to achieve artificial photosynthesis: splitting water into H2 and O2 under solar light illumination. Our group has recently invented a unique system that drives photoinduced water reduction through “Z-scheme” photosynthetic pathways. Nevertheless, that system still suffered from a low turnover number (TON) of the photocatalytic cycle (TON=4.1). We have now found and describe herein a new methodology to make significant improvements in the TON, up to around TON=14–27. For the new model systems reported herein, the quantum efficiency of the second photoinduced step in the Z-scheme photosynthesis is dramatically improved by introducing multiviologen tethers to temporarily collect the high-energy electron generated in the first photoinduced step. These are unique examples of “pigment–acceptor–catalyst triads”, which demonstrate a new effective type of artificial photosynthesis.

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Electron harvesting: Photo-hydrogen-evolving molecular devices showing substantially improved turnover numbers have been developed by introducing multiviologen tethers into a [PtCl2(2,2′-bipyridine)]-based moiety serving as a light-harvesting and H2-evolving center (see scheme). The improved photocatalytic performance is attributed to the rapidly regenerating character of the pigment due to intramolecular electron transfer from the pigment to the electron reservoirs.

28 Mar 13:23

A Bifunctional Perovskite Catalyst for Oxygen Reduction and Evolution

by Jae-Il Jung, Hu Young Jeong, Jang-Soo Lee, Min Gyu Kim, Jaephil Cho

Abstract

La0.3(Ba0.5Sr0.5)0.7Co0.8Fe0.2O3−δ is a promising bifunctional perovskite catalyst for the oxygen reduction reaction and the oxygen evolution reaction. This catalyst has circa 10 nm-scale rhombohedral LaCoO3 cobaltite particles distributed on the surface. The dynamic microstructure phenomena are attributed to the charge imbalance from the replacement of A-site cations with La3+ and local stress on Co-site sub-lattice with the cubic perovskite structure.

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The perovskite La0.3(Ba0.5Sr0.5)0.7Co0.8Fe0.2O3−δ (La0.3-5582) is introduced as a bifunctional catalyst to compete with precious metal-based catalysts. The newly introduced perovskite bears rhombohedral phase LaCoO3−δ particles on the surface of the grains.

19 Mar 10:24

Effect of Substituents on the Water Oxidation Activity of [RuII(terpy)(phen)Cl]+ Procatalysts

by Dakshika C. Wanniarachchi, Mary Jane Heeg and Cláudio N. Verani

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Inorganic Chemistry
DOI: 10.1021/ic402118u
21 Mar 00:00

Attack of the clones

by Michelle Francl

Nature Chemistry 6, 267 (2014). doi:10.1038/nchem.1906

Author: Michelle Francl

Michelle Francl suggests that self-plagiarism is a misleading term and that repeating yourself in publications isn't always a bad thing.

16 Mar 00:00

The oxidative inactivation of FeFe hydrogenase reveals the flexibility of the H-cluster

by Vincent Fourmond

Nature Chemistry 6, 336 (2014). doi:10.1038/nchem.1892

Authors: Vincent Fourmond, Claudio Greco, Kateryna Sybirna, Carole Baffert, Po-Hung Wang, Pierre Ezanno, Marco Montefiori, Maurizio Bruschi, Isabelle Meynial-Salles, Philippe Soucaille, Jochen Blumberger, Hervé Bottin, Luca De Gioia & Christophe Léger

FeFe hydrogenases, the enzymes that oxidize or produce H2, are inactivated under oxidizing conditions. Here, it is shown that this inactivation results from H2 binding to coordination positions that are normally blocked by intrinsic CO ligands. This flexibility of the active site prevents irreversible oxidative damage.

24 Mar 14:10

Well-Defined Iron Complexes as Efficient Catalysts for “Green” Atom-Transfer Radical Polymerization of Styrene, Methyl Methacrylate, and Butyl Acrylate with Low Catalyst Loadings and Catalyst Recycling

by So-ichiro Nakanishi, Mitsunobu Kawamura, Hidetomo Kai, Ren-Hua Jin, Yusuke Sunada, Hideo Nagashima

Abstract

Environmentally friendly iron(II) catalysts for atom-transfer radical polymerization (ATRP) were synthesized by careful selection of the nitrogen substituents of N,N,N-trialkylated-1,4,9-triazacyclononane (R3TACN) ligands. Two types of structures were confirmed by crystallography: “[(R3TACN)FeX2]” complexes with relatively small R groups have ionic and dinuclear structures including a [(R3TACN)Fe(μ-X)3Fe(R3TACN)]+ moiety, whereas those with more bulky R groups are neutral and mononuclear. The twelve [(R3TACN)FeX2]n complexes that were synthesized were subjected to bulk ATRP of styrene, methyl methacrylate (MMA), and butyl acrylate (BA). Among the iron complexes examined, [{(cyclopentyl)3TACN}FeBr2] (4 b) was the best catalyst for the well-controlled ATRP of all three monomers. This species allowed easy catalyst separation and recycling, a lowering of the catalyst concentration needed for the reaction, and the absence of additional reducing reagents. The lowest catalyst loading was accomplished in the ATRP of MMA with 4 b (59 ppm of Fe based on the charged monomer). Catalyst recycling in ATRP with low catalyst loadings was also successful. The ATRP of styrene with 4 b (117 ppm Fe atom) was followed by precipitation from methanol to give polystyrene that contained residual iron below the calculated detection limit (0.28 ppm). Mechanisms that involve equilibria between the multinuclear and mononuclear species were also examined.

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It’s easy being green: Structurally well-defined [(R3TACN)FeX2] complexes realized green atom-transfer radical polymerization by judicious choice of the R group on the N,N,N-trialkylated-1,4,9-triazacyclononane (R3TACN) ligands (see scheme). [{(Cyclopentyl)3TACN}FeBr2] was the best catalyst for controlled polymerization of all three monomers.

24 Mar 19:33

Theoretical Analysis of Transition-Metal Catalysts for Formic Acid Decomposition

by Jong Suk Yoo, Frank Abild-Pedersen, Jens K. Nørskov and Felix Studt

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ACS Catalysis
DOI: 10.1021/cs400664z
21 Mar 18:21

Chemistry of Iron N-Heterocyclic Carbene Complexes: Syntheses, Structures, Reactivities, and Catalytic Applications

by Korbinian Riener, Stefan Haslinger, Andreas Raba, Manuel P. Högerl, Mirza Cokoja, Wolfgang A. Herrmann and Fritz E. Kühn

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Chemical Reviews
DOI: 10.1021/cr4006439
18 Mar 19:28

Optimizing the Band Edges of Tungsten Trioxide for Water Oxidation: A First-Principles Study

by Yuan Ping and Giulia Galli

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The Journal of Physical Chemistry C
DOI: 10.1021/jp410497f
17 Mar 17:19

Superhydrophobic and Superoleophilic Miniature Device for the Collection of Oils from Water Surfaces

by Fajun Wang, Sheng Lei, Mingshan Xue, Junfei Ou, Changquan Li and Wen Li

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The Journal of Physical Chemistry C
DOI: 10.1021/jp500359v
17 Mar 18:04

Photophysical Characterization of a Helical Peptide Chromophore–Water Oxidation Catalyst Assembly on a Semiconductor Surface Using Ultrafast Spectroscopy

by Stephanie E. Bettis, Derek M. Ryan, Melissa K. Gish, Leila Alibabaei, Thomas J. Meyer, Marcey L. Waters and John M. Papanikolas

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The Journal of Physical Chemistry C
DOI: 10.1021/jp410646u
07 Mar 15:33

Unified View of Oxidative C–H Bond Cleavage and Sulfoxidation by a Nonheme Iron(IV)–Oxo Complex via Lewis Acid-Promoted Electron Transfer

by Jiyun Park, Yuma Morimoto, Yong-Min Lee, Wonwoo Nam and Shunichi Fukuzumi

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Inorganic Chemistry
DOI: 10.1021/ic403124u
07 Mar 15:32

Mechanistic Insights into Ruthenium-Catalyzed Production of H2 and CO2 from Methanol and Water: A DFT Study

by Xinzheng Yang

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ACS Catalysis
DOI: 10.1021/cs500061u
10 Mar 12:12

Ruthenium-Catalyzed Reduction of Carbon Dioxide to Formaldehyde

by Sébastien Bontemps, Laure Vendier and Sylviane Sabo-Etienne

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Journal of the American Chemical Society
DOI: 10.1021/ja500708w
06 Mar 19:34

Photoelectrochemical hydrogen production from biomass derivatives and water

Chem. Soc. Rev., 2014, Advance Article
DOI: 10.1039/C3CS60392J, Tutorial Review
Xihong Lu, Shilei Xie, Hao Yang, Yexiang Tong, Hongbing Ji
Photoelectrochemical hydrogen production from renewable biomass derivatives and water is a promising approach to produce green chemical fuels.
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06 Mar 19:34

Photoinduced electron transfer across molecular bridges: electron- and hole-transfer superexchange pathways

Chem. Soc. Rev., 2014, Advance Article
DOI: 10.1039/C3CS60463B, Tutorial Review
Mirco Natali, Sebastiano Campagna, Franco Scandola
A tutorial review outlining a general conceptual framework, based on superexchange, to discuss the role of chemical bridges in photoinduced electron transfer processes.
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04 Mar 11:13

Improved O2 Evolution from Water Splitting Reaction over Tetragonal BiVO4 by Er3+, Y3+ Co-doping

Catal. Sci. Technol., 2014, Accepted Manuscript
DOI: 10.1039/C4CY00050A, Paper
Sergio Obregon, Gerardo Colon
Erbium-Yttrium co-doped BiVO4 with tetragonal structure are synthesized by means of a surfactant free hydrothermal method. The studied photocatalysts show good photoactivities under sun-like excitation for the degradation of Methylene...
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18 Feb 15:54

Reversible Interconversion Between a Monomeric Iridium Hydroxo and a Dinuclear Iridium μ-Oxo Complex

by Richard J. Burford, Warren E. Piers, Daniel H. Ess and Masood Parvez

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Journal of the American Chemical Society
DOI: 10.1021/ja412650s
20 Feb 05:50

Direct Observation of Reversible Electronic Energy Transfer Involving an Iridium Center

by Sergey A. Denisov, Yanouk Cudré, Peter Verwilst, Gediminas Jonusauskas, Marta Marín-Suárez, Jorge Fernando Fernández-Sánchez, Etienne Baranoff and Nathan D. McClenaghan

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Inorganic Chemistry
DOI: 10.1021/ic4030712
20 Feb 14:56

Development of Molecular Electrocatalysts for Energy Storage

by Daniel L. DuBois

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Inorganic Chemistry
DOI: 10.1021/ic4026969
20 Feb 22:20

How Important are Impurities in Catalysis? An Example from Ring-Closing Metathesis

by Christa Lübbe, Andreas Dumrath, Helfried Neumann, Marion Schäffer, Ralf Zimmermann, Matthias Beller, Renat Kadyrov

Abstract

The dramatic effect of substrate impurities on the performance of a specific ruthenium catalyst system is demonstrated in the benchmark metathesis reaction of diethyl diallylmalonate. Based on detailed two-dimensional GC–time-of-flight MS measurements, the significant influence of small amounts of different contaminations, especially various organic halides, is shown. This work serves as an incisive example of the importance of impurities to catalyst performance, also in homogeneous catalysis, which is often ignored in academic research.

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Pure or not pure, that is the question: The presence of small amounts of impurities has a dramatic influence on the reactivity and selectivity of a novel ruthenium-based ring-closing metathesis (RCM) catalyst.

20 Feb 00:00

Photocatalysis: Water is the solution

by Ruth Doherty

Nature Chemistry 6, 168 (2014). doi:10.1038/nchem.1884

Author: Ruth Doherty

20 Feb 08:50

Recent advances in heterogeneous selective oxidation catalysis for sustainable chemistry

Chem. Soc. Rev., 2014, Advance Article
DOI: 10.1039/C3CS60282F, Review Article
Zhen Guo, Bin Liu, Qinghong Zhang, Weiping Deng, Ye Wang, Yanhui Yang
Selective oxidations of CH4, alcohols and CO over heterogeneous catalysts are reviewed from the viewpoint of green and sustainable chemistry.
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28 Feb 09:53

Catalysis for biomass and CO2 use through solar energy: opening new scenarios for a sustainable and low-carbon chemical production

Chem. Soc. Rev., 2014, Advance Article
DOI: 10.1039/C3CS60396B, Tutorial Review
Paola Lanzafame, Gabriele Centi, Siglinda Perathoner
The use of biomass, bio-waste and CO2 derived raw materials, the latter synthesized using H2 produced using renewable energy sources, opens new scenarios to develop a sustainable and low carbon chemical production.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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05 Mar 08:10

Photochemically-Generated Intermediates in Synthesis. By Angelo Albini and Maurizio Fagnoni.

by Axel G. Griesbeck
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John Wiley and Sons, Hoboken, 2013. 380 pp., hardcover, € 132.00.—ISBN 978-0470915349

03 Mar 15:32

Copper Active Sites in Biology

by Edward I. Solomon, David E. Heppner, Esther M. Johnston, Jake W. Ginsbach, Jordi Cirera, Munzarin Qayyum, Matthew T. Kieber-Emmons, Christian H. Kjaergaard, Ryan G. Hadt and Li Tian

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Chemical Reviews
DOI: 10.1021/cr400327t