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2D catalyst

Lei-Lei Liu, Jing Chen, Cai-Xia Yu, Wen-Xing Lv, Hui-Ying Yu, Xiao-Qing Cui, Lin Liu
Nitrobenzene (NB) is a widespread and highly toxic organic pollutant in water, and consequently its detection and removal have attracted considerable attention. In the present study, we designed and synthesized a novel coordination polymer, [AgL0.5(NO3)]n (1), {L = 25,26,27,28-tetra[(3-pyridylmethyl)oxy]calix[4]arene}, from AgNO3 and a tetra-pyridyl-functionalized calix[4]arene ligand, which possessed a 2D network based on [Ag4L(NO3)4] units. The 1-modified glassy carbon electrode (1/GCE) exhibited good electrocatalytic activity toward the reduction of NB, offering the selective detection of NB in a wide linear range (1-2450 μM) and a low detection limit (0...
December 1, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Jingwen Zhu, Emilie-Laure Zins, Mohammad Esmaïl Alikhani
For over a decade, amine-borane has been considered as a potential chemical hydrogen vector in the context of a search for cleaner energy sources. When catalyzed by organometallic complexes, the reaction mechanisms currently considered involve the formation of β-BH agostic intermediates. A thorough understanding of these intermediates may constitute a crucial step toward the identification of ideal catalysts. Topological approaches such as QTAIM and ELF revealed to be particularly suitable for the description of β-agostic interactions...
December 2016: Journal of Molecular Modeling
Renhao Dong, Zhikun Zheng, Diana Tranca, Jian Zhang, Naisa Chandrasekhar, Shaohua Liu, Xiaodong Zhuang, Gotthard Seifert, Xinliang Feng
Carbon electrocatalysts consisting of metal complexes (such as MNx and MSx) are promising candidates for use as alternatives to high-cost Pt catalysts for the hydrogen evolution reaction (HER). However, the exact HER active sites remain elusive. Here, we selectively incorporate the molecular metal dithiolene-diamine (MS2N2, M=Co and Ni), metal bis(dithiolene) (MS4), and metal bis(diamine) (MN4) complexes into carbon-rich 2D metal-organic frameworks (2D MOFs) as model carbon electrocatalysts. The 2D MOF single layers, powders, and composites with graphene are thus prepared and devote definite active sites for H2 generation...
November 22, 2016: Chemistry: a European Journal
Gillian Collins, Eileen Armstrong, David McNulty, Sally O'Hanlon, Hugh Geaney, Colm O'Dwyer
This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems...
2016: Science and Technology of Advanced Materials
Courtney A Downes, Smaranda C Marinescu
Immobilization of metal complexes to electrode surfaces has emerged as an attractive strategy to combine homogeneous and heterogeneous catalysis. We recently reported the immobilization of cobalt dithiolene catalytic units via incorporation into extended one and two dimensional (1D and 2D) frameworks. We extend here this methodology to the formation of 1D nickel, iron, and zinc dithiolene coordination polymers based on benzene-1,2,4,5-tetrathiolate (BTT) frameworks and investigate their catalytic H2-evolving activities under fully aqueous conditions...
November 22, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Changzhi Li, Haiwei Guo, Bo Zhang, Tao Dai, Zaojuan Qi, Aiqin Wang, Tao Zhang, Jianwei Ji
Lignins isolated from representative hardwood, softwood and grass materials, were effectively hydrocracked to aromatics catalyzed by W2C/AC. The effects of botanical species and fractionation methods on lignin structure and the activity of tungsten carbide were detailed studied. GPC, FT-IR, elemental analysis, 2D HSQC NMR showed that all the extracted samples shared the basic skeleton of lignin, whereas the fractionation method significantly affected the structure. Organosolv process provided lignin with structure more similar to the native lignin, which was liable to be depolymerized by W2C/AC catalyst...
November 10, 2016: ChemSusChem
Guisheng Zeng, Weiping Li, Suqin Ci, Jingchun Jia, Zhenhai Wen
Nickel oxide-decorated graphene nanosheet (NiO/GNS), as a novel non-enzymatic electrocatalyst for glucose oxidation reaction (GOR), was synthesized through a facile hydrothermal route followed by the heat treatment. The successful synthesis of NiO/GNS was characterized by a series of techniques including XRD, BET, SEM and TEM. Significantly, the NiO/GNS catalyst show excellent catalytic activity toward GOR, and was employed to develop a sensitive non-enzymatic glucose sensor. The developed glucose sensor could response to glucose in a wide range from 5 μM-4...
November 2, 2016: Scientific Reports
Jing Yang, Kai Wang, Jixin Zhu, Chao Zhang, Tianxi Liu
Semiconductor heterostructures of two-dimensional (2D) transition metal disulfide (TMD) have opened up approaches toward the integration of each functions and implementations in novel energy and electronic devices. However, engineering TMD-based homostructures with tailored properties is still challenging. Herein, we demonstrate a solution-processed growth of vertically aligned 1T-MoS2 using liquid-phase exfoliated 2H-MoS2 as self templates. The unique MoS2-based homostructures not only provide more exposed active sites in edge and basal plane for the electrocatalytic hydrogen evolution reaction (HER), but also improve the mass transfer due to the introduction of high packing porosity...
November 1, 2016: ACS Applied Materials & Interfaces
Encarnación Torralba, Sylvain Le Gall, Raphaël Lachaume, Vincent Magnin, Joseph Harari, Mathieu Halbwax, Jean-Pierre Vilcot, Christine Cachet-Vivier, Stéphane Bastide
An in-depth study of metal assisted chemical etching (MACE) of p-type c-Si in HF/H2O2 aqueous solutions using Pt nanoparticles as catalysts is presented. Combination of cyclic voltammetry, open circuit measurements, chronoamperometry, impedance spectroscopy, and 2D band bending modeling of the metal/semiconductor/electrolyte interfaces at the nanoscale and under different etching conditions allows gaining physical insights into this system. Additionally, in an attempt to mimic the etching conditions, the modeling has been performed with a positively biased nanoparticle buried in the Si substrate...
November 3, 2016: ACS Applied Materials & Interfaces
Meng-Juan Zhang, Hong-Xi Li, Hai-Yan Li, Jian-Ping Lang
Solvothermal reactions of 5-phenylpyrimidine-2-thiol (5-phpymtH) with equimolar CuBr afforded one hexanuclear cluster [Cu6(μ3-5-phpymt)6] (1) along with a tetranuclear by-product [{(Cu2Br)(μ-5-phpymtH)}(μ3-5-phpymt)]2 (2). A two dimensional (2D) polymer [Cu4(μ5-5-phpymt)2(μ-Br)2]n (3) was isolated from the reaction of 5-phpymtH with two equiv. of CuBr. Analogous reactions of 5-phpymtH with one or four equiv. of CuI produced one tetranuclear cluster [{Cu2(μ-5-phpymtH)(μ-5-phpymt)}(μ3-I)]2 (4) and one 2D polymer [Cu6I2(μ4-I)2(μ4-5-phpymt)2]n (5)...
October 21, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Rico Gutzler
Conjugated polymers find widespread application in (opto)electronic devices, sensing, and as catalysts. Their common one-dimensional structure can be extended into the second dimension to create conjugated planar sheets of covalently linked molecules. Extending π-conjugation into the second dimension unlocks a new class of semiconductive polymers which as a consequence of their unique electronic properties can find usability in numerous applications. In this article the theoretical band structures of a set of conjugated 2D polymers are compared and information on the important characteristics band gap and valence/conduction band dispersion is extracted...
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
F Rietzler, B May, H-P Steinrück, F Maier
Combining in vacuo deposition of ultrathin ionic liquid (UTIL) films with angle-resolved X-ray photoelectron spectroscopy (ARXPS), we demonstrate that by deposition of submonolayer amounts of Pd onto Au(111) the initial growth mode of the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([C2C1Im][OTf]) can be switched from three-dimensional (3D) to two-dimensional (2D) growth, that is, from non-wetting to wetting. On clean Au(111), pronounced 3D growth occurs on top of an initially formed 2D wetting layer with cations and anions next to each other in a checkerboard arrangement...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Wei An, Ping Liu
Using the TiO2(110)-supported Pd7 cluster as a model catalyst, we have identified from density functional theory calculations that the dynamics of supported metal nanoparticles, particularly at the sub-nanometer scale, can be complex under reactive environments. Increasing the CO coverage can induce a structural transformation from Pd7-3D/TiO2(110) at low coverage to Pd7-2D/TiO2(110) at the saturation coverage wherein CO saturation-driven Pd7-2D/TiO2(110) structure displays superior CO oxidation activity at the interfacial sites, which are highly active for catalyzing O2 dissociation and CO oxidation via bifunctional synergy...
November 16, 2016: Physical Chemistry Chemical Physics: PCCP
Ju-Hwan Oh, Hyunku Shin, Jong Yun Choi, Hee Won Jung, Yeonho Choi, Jae-Seung Lee
Noble metal bimetallic nanomaterials have attracted a great deal of attention owing to the strong correlation between their morphology and chemical and physical properties. Even though the synthetic strategies for controlling the shapes of monometallic nanomaterials such as gold (Au) and silver (Ag) are well-developed, limited advances have been made with Au/Ag bimetallic nanomaterials to date. In this work, we demonstrate a highly complex in-plate and on-plate structural control of Au/Ag bimetallic nanoplates (Au/AgBNPLs) in contrast to conventional, simply structured, 1D and 2D, branched, and polyhedral nanomaterials...
October 3, 2016: ACS Applied Materials & Interfaces
Hyeyoung Shin, Yoonhoo Ha, Hyungjun Kim
Toward a sustainable carbon cycle, electrochemical conversion of CO2 into valuable fuels has drawn much attention. However, sluggish kinetics and a substantial overpotential, originating from the strong correlation between the adsorption energies of intermediates and products, are key obstacles of electrochemical CO2 conversion. Here we show that 2D covalent metals with a zero band gap can overcome the intrinsic limitation of conventional metals and metal alloys and thereby substantially decrease the overpotential for CO2 reduction because of their covalent characteristics...
October 4, 2016: Journal of Physical Chemistry Letters
Lichen Liu, Urbano Díaz, Raul Arenal, Giovanni Agostini, Patricia Concepción, Avelino Corma
Single metal atoms and metal clusters have attracted much attention thanks to their advantageous capabilities as heterogeneous catalysts. However, the generation of stable single atoms and clusters on a solid support is still challenging. Herein, we report a new strategy for the generation of single Pt atoms and Pt clusters with exceptionally high thermal stability, formed within purely siliceous MCM-22 during the growth of a two-dimensional zeolite into three dimensions. These subnanometric Pt species are stabilized by MCM-22, even after treatment in air up to 540 °C...
September 26, 2016: Nature Materials
Min-Ho Jin, Duckkyu Oh, Ju-Hyoung Park, Chun-Boo Lee, Sung-Wook Lee, Jong-Soo Park, Kwan-Young Lee, Dong-Wook Lee
For the application of formic acid as a liquid organic hydrogen carrier, development of efficient catalysts for dehydrogenation of formic acid is a challenging topic, and most studies have so far focused on the composition of metals and supports, the size effect of metal nanoparticles, and surface chemistry of supports. Another influential factor is highly desired to overcome the current limitation of heterogeneous catalysis for formic acid decomposition. Here, we first investigated the effect of support pore structure on formic acid decomposition performance at room temperature by using mesoporous silica materials with different pore structures such as KIE-6, MCM-41, and SBA-15, and achieved the excellent catalytic activity (TOF: 593 h(-1)) by only controlling the pore structure of mesoporous silica supports...
September 26, 2016: Scientific Reports
Diep Dinh Phong, Jin Hur
Non-catalytic and catalytic photodegradation of effluent dissolved organic matter (EfDOM) was examined under two different light sources (UVA and UVC). The degradation behavior was tracked by dissolved organic carbon (DOC), UV absorbance, and different fluorescent components. Catalytic UV irradiation resulted in much higher degradation rates than those without photocatalysts (TiO2 and ZnO) regardless of the tracking variables. For non-catalytic degradation, the highest removal rates of UV absorbance were found at wavelengths close to the irradiation of either UVC or UVA, while the photocatalytic degradation rates were consistently higher at longer wavelengths...
November 15, 2016: Water Research
Sara Blomberg, Jianfeng Zhou, Johan Gustafson, Johan Zetterberg, Edvin Lundgren
In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS)...
November 16, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Xiuren Wang, Xing Han, Jie Zhang, Xiaowei Wu, Yan Liu, Yong Cui
There have been breakthroughs in the development of covalent organic frameworks (COFs) with tunability of composition, structure, and function, but the synthesis of chiral COFs remains a great challenge. Here we report the construction of two-dimensional COFs with chiral functionalities embedded into the frameworks by imine condensations of enantiopure TADDOL-derived tetraaldehydes with 4,4'-diaminodiphenylmethane. Powder X-ray diffraction and computer modeling together with pore size distribution analysis show that one COF has a twofold-interpenetrated grid-type network and the other has a non-interpenetrated grid network...
September 28, 2016: Journal of the American Chemical Society
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