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22 Jul 17:17

Water oxidation catalysed by iron complex of N,N[prime or minute]-dimethyl-2,11-diaza[3,3](2,6)pyridinophane. Spectroscopy of iron-oxo intermediates and density functional theory calculations

Chem. Sci., 2015, Advance Article
DOI: 10.1039/C5SC01680K, Edge Article
Open Access Open Access
Creative Commons Licence&nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Wai-Pong To, Toby Wai-Shan Chow, Chun-Wai Tse, Xiangguo Guan, Jie-Sheng Huang, Chi-Ming Che
FeIV=O and/or FeV=O intermediates are suggested to be involved in water oxidation with [NH4]2[CeIV(NO3)6], NaIO4, or Oxone catalyzed by [FeIII(L1)Cl2]+ (1) on the basis of spectroscopic measurements and DFT calculations.
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20 Jul 14:34

Gold-Coated Cobalt Ferrite Nanoparticles via Methionine-Induced Reduction

by Agnė Mikalauskaitė, Rokas Kondrotas, Gediminas Niaura and Aru̅nas Jagminas

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The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.5b03528
21 Jul 19:20

Rechargeable Hydrogen Storage System Based on the Dehydrogenative Coupling of Ethylenediamine with Ethanol

by Peng Hu, Yehoshoa Ben-David, David Milstein

Abstract

A novel and simple hydrogen storage system was developed, based on the dehydrogenative coupling of inexpensive ethylenediamine with ethanol to form diacetylethylenediamine. The system is rechargeable and utilizes the same ruthenium pincer catalyst for both hydrogen loading and unloading procedures. It is efficient and uses a low catalyst loading. Repetitive reversal reactions without addition of new catalyst result in excellent conversions in both the dehydrogenation and hydrogenation procedures in three cycles.

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In support of the hydrogen economy: An efficient and simple homogeneous hydrogen carrier system was developed based on the dehydrogenative coupling of ethylenediamine with ethanol to form diacetylethylenediamine. The same ruthenium pincer catalyst is used for both hydrogen loading and unloading reactions.

17 Jul 14:46

In Situ-Generated Co0-Co3O4/N-Doped Carbon Nanotubes Hybrids as Efficient and Chemoselective Catalysts for Hydrogenation of Nitroarenes

by Zhongzhe Wei, Jing Wang, Shanjun Mao, Diefeng Su, Haiyan Jin, Yihe Wang, Fan Xu, Haoran Li and Yong Wang

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ACS Catalysis
DOI: 10.1021/acscatal.5b00737
13 Jul 20:09

Organic Dye-Sensitized Tandem Photoelectrochemical Cell for Light Driven Total Water Splitting

by Fusheng Li, Ke Fan, Bo Xu, Erik Gabrielsson, Quentin Daniel, Lin Li and Licheng Sun

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b04856
16 Jul 00:00

A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells

by Fei Guo

Article

The efficiency of a single-junction photovoltaic cell is constrained by the Shockley-Queisser limit. Here, the authors adopt a triple-junction configuration which relaxes material and current-matching constraints, providing a generic strategy for advancing the efficiency roadmap of photovoltaic technologies.

Nature Communications doi: 10.1038/ncomms8730

Authors: Fei Guo, Ning Li, Frank W. Fecher, Nicola Gasparini, Cesar Omar Ramirez Quiroz, Carina Bronnbauer, Yi Hou, Vuk V. Radmilović, Velimir R. Radmilović, Erdmann Spiecker, Karen Forberich, Christoph J. Brabec

15 Jul 00:00

Why we are teaching science wrong, and how to make it right

by M. Mitchell Waldrop

Why we are teaching science wrong, and how to make it right

Nature 523, 7560 (2015). http://www.nature.com/doifinder/10.1038/523272a

Author: M. Mitchell Waldrop

Active problem-solving confers a deeper understanding of science than does a standard lecture. But some university lecturers are reluctant to change tack.

15 Jul 00:00

Lifelong learning: Science professors need leadership training

by Charles E. Leiserson

Lifelong learning: Science professors need leadership training

Nature 523, 7560 (2015). doi:10.1038/523279a

Authors: Charles E. Leiserson & Chuck McVinney

To drive discovery, scientists heading up research teams large and small need to learn how people operate, argue Charles E. Leiserson and Chuck McVinney.

10 Jul 08:28

Catalyst characterisation techniques and reaction cells operating at realistic conditions; towards acquisition of kinetically relevant information

Catal. Sci. Technol., 2015, Advance Article
DOI: 10.1039/C5CY00269A, Perspective
Nikolaos E. Tsakoumis, Andrew P. E. York, De Chen, Magnus Ronning
Catalyst characterisation techniques and reaction cells operating at realistic conditions; towards acquisition of kinetically relevant information.
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16 Jul 12:39

Perovskite Solar Cells with Near 100% Internal Quantum Efficiency Based on Large Single Crystalline Grains and Vertical Bulk Heterojunctions

by Bin Yang, Ondrej Dyck, Jonathan Poplawsky, Jong Keum, Alexander Puretzky, Sanjib Das, Ilia Ivanov, Christopher Rouleau, Gerd Duscher, David Geohegan and Kai Xiao

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b03144
01 Jun 13:31

Stable Cobalt Nanoparticles and Their Monolayer Array as an Efficient Electrocatalyst for Oxygen Evolution Reaction

by Liheng Wu, Qing Li, Cheng Hao Wu, Huiyuan Zhu, Adriana Mendoza-Garcia, Bo Shen, Jinghua Guo and Shouheng Sun

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b04142
12 Jun 15:55

Simple and Efficient System for Combined Solar Energy Harvesting and Reversible Hydrogen Storage

by Lu Li, Xiaoyue Mu, Wenbo Liu, Zetian Mi and Chao-Jun Li

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b03505
10 Jun 00:00

Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal–nitrogen coordination

by Kara Strickland

Article

The active site of many non-noble metal cathodic oxygen reduction catalysts consists of a nitrogen-corodinated transition metal. Here, the authors report an iron-based electrocatalyst devoid of iron–nitrogen coordination, and demonstrate its high activity in acid and alkaline media.

Nature Communications doi: 10.1038/ncomms8343

Authors: Kara Strickland, Elise Miner, Qingying Jia, Urszula Tylus, Nagappan Ramaswamy, Wentao Liang, Moulay-Tahar Sougrati, Frédéric Jaouen, Sanjeev Mukerjee

11 Jun 00:00

Efficient photosynthesis of carbon monoxide from CO2 using perovskite photovoltaics

by Marcel Schreier

Article

Artificial photosynthesis is a means of harnessing solar energy to generate fuels but has traditionally been exploited for the generation of hydrogen. Here, Schreier et al . instead employ a perovskite photovoltaic device to effect the solar conversion of CO 2 to CO with high efficiency.

Nature Communications doi: 10.1038/ncomms8326

Authors: Marcel Schreier, Laura Curvat, Fabrizio Giordano, Ludmilla Steier, Antonio Abate, Shaik M. Zakeeruddin, Jingshan Luo, Matthew T. Mayer, Michael Grätzel

15 Jun 00:00

In situ oxidation of carbon-encapsulated cobalt nanocapsules creates highly active cobalt oxide catalysts for hydrocarbon combustion

by Han Wang

Article

Palladium is an effective but expensive catalyst used in catalytic converters. Here, the authors show that defective Co 3 O 4 nanocrystals, synthesized via oxidation of carbon-encapsulated cobalt nanoparticles, display similar or even comparable catalytic activity to palladium for hydrocarbon combustion.

Nature Communications doi: 10.1038/ncomms8181

Authors: Han Wang, Chunlin Chen, Yexin Zhang, Lixia Peng, Song Ma, Teng Yang, Huaihong Guo, Zhidong Zhang, Dang Sheng Su, Jian Zhang

19 May 16:02

Rational design of self-assembly pathways [Chemistry]

by Jacobs, W. M., Reinhardt, A., Frenkel, D.
The field of complex self-assembly is moving toward the design of multiparticle structures consisting of thousands of distinct building blocks. To exploit the potential benefits of structures with such “addressable complexity,” we need to understand the factors that optimize the yield and the kinetics of self-assembly. Here we use a...
11 Jun 18:50

[Report] High-performance photovoltaic perovskite layers fabricated through intramolecular exchange

by Woon Seok Yang
The band gap of formamidinium lead iodide (FAPbI3) perovskites allows broader absorption of the solar spectrum relative to conventional methylammonium lead iodide (MAPbI3). Because the optoelectronic properties of perovskite films are closely related to film quality, deposition of dense and uniform films is crucial for fabricating high-performance perovskite solar cells (PSCs). We report an approach for depositing high-quality FAPbI3 films, involving FAPbI3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in PbI2 with formamidinium iodide. This process produces FAPbI3 films with (111)-preferred crystallographic orientation, large-grained dense microstructures, and flat surfaces without residual PbI2. Using films prepared by this technique, we fabricated FAPbI3-based PSCs with maximum power conversion efficiency greater than 20%. Authors: Woon Seok Yang, Jun Hong Noh, Nam Joong Jeon, Young Chan Kim, Seungchan Ryu, Jangwon Seo, Sang Il Seok
10 Jun 11:25

Light converting phosphor-based photocatalytic composites

Catal. Sci. Technol., 2015, Advance Article
DOI: 10.1039/C5CY00622H, Minireview
Xinjuan Liu, Haipeng Chu, Jinliang Li, Lengyuan Niu, Can Li, Huili Li, Likun Pan, Chang Q. Sun
Light-conversion phosphor-based composites including up-conversion, down-conversion, and long afterglow phosphor-semiconductors for efficient photocatalysis are summarized.
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05 May 18:52

Transient Absorption Spectroscopy of Anatase and Rutile: The Impact of Morphology and Phase on Photocatalytic Activity

by Xiuli Wang, Andreas Kafizas, Xiaoe Li, Savio J. A. Moniz, Philip J. T. Reardon, Junwang Tang, Ivan P. Parkin and James R. Durrant

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The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.5b01858
18 May 15:36

In Situ Resonant UV-Raman Spectroscopy of Polycyclic Aromatic Hydrocarbons

by Matteo Signorile, Francesca Bonino, Alessandro Damin and Silvia Bordiga

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The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.5b02209
30 Mar 12:54

In-Depth Studies on Rapid Photochemical Activation of Various Sol–Gel Metal Oxide Films for Flexible Transparent Electronics

by Sungjun Park, Kwang-Ho Kim, Jeong-Wan Jo, Sujin Sung, Kyung-Tae Kim, Won-June Lee, Jaekyun Kim, Hyun Jae Kim, Gi-Ra Yi, Yong-Hoon Kim, Myung-Han Yoon, Sung Kyu Park

Despite intensive research on photochemical activation of sol–gel metal oxide materials, the relatively long processing time and lack of deep understanding of the underlying chemical courses have limited their broader impact on diverse materials and applications such as thin-film electronics, photovoltaics, and catalysts. Here, in-depth studies on the rapid photochemical activation of diverse sol–gel oxide films using various spectroscopic and electrical investigations for the underlying physicochemical mechanism are reported. Based on the exhaustive chemical and physical analysis, it is noted that deep ultraviolet-promoted rapid film formation such as densification, polycondensation, and impurity decomposition is possible within 5 min via in situ radical-mediated reactions. Finally, the rapid fabrication of all-solution metal oxide thin-film-transistor circuitry, which exhibits stable and reliable electrical performance with a mobility of >12 cm2 V−1 s−1 and an oscillation frequency of >650 kHz in 7-stage ring oscillator even after bending at a radius of <1 mm is demonstrated.

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The general physicochemical mechanisms underlying photoactivated sol–gel reactions are described, with comprehensive chemical and structural analysis inducing rapid (<5 min) fabrication of various metal oxide films at low temperatures (<150 °C), and all-solution processed high-performance electronic devices and circuitry on ultrathin polymeric substrates are demonstrated. This will open new possibilities to prepare future electronic materials in a fast, scalable, and economic manner.

18 May 18:11

Sol–Gel Metal Oxides: In-Depth Studies on Rapid Photochemical Activation of Various Sol–Gel Metal Oxide Films for Flexible Transparent Electronics (Adv. Funct. Mater. 19/2015)

by Sungjun Park, Kwang-Ho Kim, Jeong-Wan Jo, Sujin Sung, Kyung-Tae Kim, Won-June Lee, Jaekyun Kim, Hyun Jae Kim, Gi-Ra Yi, Yong-Hoon Kim, Myung-Han Yoon, Sung Kyu Park
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The front cover demonstrates the fabrication of sol–gel derived metal oxide electronic devices and circuits by low-temperature photochemical activation via in-situ radical-mediated reactions. On page 2807, M.-H. Yoon, S. K. Park, and colleagues show that the rapid photoactivation process enables the conversion of the sol–gel precursors into metal oxide electronic materials directly on ultra-flexible plastic substrates, which will serve as a general methodology in a rapid, scalable, and economic manner.

06 May 12:51

Catalytic Water Oxidation by a Molecular Ruthenium Complex: Unexpected Generation of a Single-Site Water Oxidation Catalyst

by Wangchuk Rabten, Markus D. Kärkäs, Torbjörn Åkermark, Hong Chen, Rong-Zhen Liao, Fredrik Tinnis, Junliang Sun, Per E. M. Siegbahn, Pher G. Andersson and Björn Åkermark

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Inorganic Chemistry
DOI: 10.1021/ic502755c
28 Apr 16:02

An Mn(V)-oxo role in splitting water? [Chemistry]

by Britt, R. D., Suess, D. L. M., Stich, T. A.
The oxygen-evolving complex (OEC) of photosystem II (PSII) uses the full spectrum of visible light to oxidize water, producing O2 and bioactivated electrons and protons (1, 2). The unique nature of this crucial bioenergetic reaction has led to much interest in harnessing analogous photochemistry and catalysis for energy storage, with...
01 May 00:00

Mammoth genomes provide recipe for creating Arctic elephants

by Ewen Callaway

Mammoth genomes provide recipe for creating Arctic elephants

Nature 521, 7550 (2015). http://www.nature.com/doifinder/10.1038/nature.2015.17462

Author: Ewen Callaway

Catalogue of genetic differences between woolly mammoths and elephants reveals how ice-age giants braved the cold.

07 May 18:52

[Report] A synthetic Mn4Ca-cluster mimicking the oxygen-evolving center of photosynthesis

by Chunxi Zhang
Photosynthetic splitting of water into oxygen by plants, algae, and cyanobacteria is catalyzed by the oxygen-evolving center (OEC). Synthetic mimics of the OEC, which is composed of an asymmetric manganese-calcium-oxygen cluster bound to protein groups, may promote insight into the structural and chemical determinants of biological water oxidation and lead to development of superior catalysts for artificial photosynthesis. We synthesized a Mn4Ca-cluster similar to the native OEC in both the metal-oxygen core and the binding protein groups. Like the native OEC, the synthetic cluster can undergo four redox transitions and shows two magnetic resonance signals assignable to redox and structural isomerism. Comparison with previously synthesized Mn3CaO4-cubane clusters suggests that the fourth Mn ion determines redox potentials and magnetic properties of the native OEC. Authors: Chunxi Zhang, Changhui Chen, Hongxing Dong, Jian-Ren Shen, Holger Dau, Jingquan Zhao
07 May 18:52

[This Week in Science] Mimicking the oxygen evolution center

by Nicholas S. Wigginton
Author: Nicholas S. Wigginton
15 May 12:08

Research progress of perovskite materials in photocatalysis- and photovoltaics-related energy conversion and environmental treatment

Chem. Soc. Rev., 2015, 44,5371-5408
DOI: 10.1039/C5CS00113G, Review Article
Wei Wang, Moses O. Tade, Zongping Shao
Perovskite materials are shown to be active in the applications of photocatalysis- and photovoltaics-related energy conversion and environmental treatment.
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05 May 13:37

Formation of Urban Fine Particulate Matter

by Renyi Zhang, Gehui Wang, Song Guo, Misti L. Zamora, Qi Ying, Yun Lin, Weigang Wang, Min Hu and Yuan Wang

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Chemical Reviews
DOI: 10.1021/acs.chemrev.5b00067
12 May 16:50

Can Dynamics Be Responsible for the Complex Multipeak Infrared Spectra of NO Adsorbed to Copper(II) Sites in Zeolites?

by Florian Göltl, Philippe Sautet, Ive Hermans

Abstract

Copper-exchanged SSZ-13 is a very efficient material in the selective catalytic reduction of NOx using ammonia (deNOx-SCR) and characterizing the underlying distribution of copper sites in the material is of prime importance to understand its activity. The IR spectrum of NO adsorbed to divalent copper sites are modeled using ab initio molecular dynamics simulations. For most sites, complex multi-peak spectra induced by the thermal motion of the cation as well as the adsorbate are found. A finite temperature spectrum for a specific catalyst was constructed, which shows excellent agreement with previously reported data. Additionally these findings allow active and inactive species in deNOx-SCR to be identified. To the best of our knowledge, this is the first time such complex spectra for single molecules adsorbed to single active centers have been reported in heterogeneous catalysis, and we expect similar effects to be important in a large number of systems with mobile active centers.

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Theory and practice: The IR spectra of NO adsorbed on Cu centers in a copper-containing zeolite were modeled using molecular dynamics simulations. The spectra are complex, which is due to the thermal motions of the cations and the adsorbates, and are in excellent agreement with the experimental spectra.