Read by QxMD icon Read

2D catalyst

Encarnación Torralba, Sylvain LE Gall, Raphaël Lachaume, Vincent Magnin, Joseph Harari, Mathieu Halbwax, Jean-Pierre Vilcot, Christine Cachet-Vivier, Stephane 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, chrono-amperometry, impedance spectroscopy and 2D band bending modelling of the Metal/Semiconductor/Electrolyte inter-faces 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 modelling has been performed with a positively biased nanoparticle buried in the Si substrate...
October 26, 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...
September 19, 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
Laura M Kiefer, Kevin J Kubarych
We have identified an unexpected signature of non-Gaussian dynamics in a conventional 2D IR measurement on a system with rapid intermolecular vibrational energy transfer. In a ternary mixture of the CO2 reduction photocatalyst, ReCl(bpy)(CO)3, NaSCN, and THF solvent, preferential association between the metal carbonyl catalyst and the NaSCN ion pairs facilitates intermolecular energy transfer on a few picoseconds time scale. Monitoring the cross peak between the highest frequency metal carbonyl band and the CN bands of NaSCN contact ion pairs, we find a striking time evolution of the cross-peak position on the detection axis...
October 6, 2016: Journal of Physical Chemistry Letters
Jeffrey B Chou, Xin-Hao Li, Yu Wang, David P Fenning, Asmaa Elfaer, Jaime Viegas, Mustapha Jouiad, Yang Shao-Horn, Sang-Gook Kim
Plasmon assisted photoelectric hot electron collection in a metal-semiconductor junction can allow for sub-bandgap optical to electrical energy conversion. Here we report hot electron collection by wafer-scale Au/TiO<sub>2</sub> metallic-semiconductor photonic crystals (MSPhC), with a broadband photoresponse below the bandgap of TiO<sub>2</sub>. Multiple absorption modes supported by the 2D nano-cavity structure of the MSPhC extend the photon-metal interaction time and fulfill a broadband light absorption...
September 5, 2016: Optics Express
Qisheng Wu, Jun-Jie Zhang, Peipei Hao, Zhongyang Ji, Shuai Dong, Chongyi Ling, Qian Chen, Jinlan Wang
On the basis of global structure search and density functional theory calculations, we predict a new class of two-dimensional (2D) materials, titanium silicide (Ti2Si, TiSi2, and TiSi4) monolayers. They are proved to be energetically, dynamically, and thermally stable and own excellent mechanical properties. Among them, Ti2Si is a ferromagnetic metal with a magnetic moment of 1.37 μB/cell, while TiSi2 is an ideal catalyst for the hydrogen evolution reaction with a nearly zero free energy of hydrogen adsorption...
October 6, 2016: Journal of Physical Chemistry Letters
Zheng Kun Yang, Ling Lin, An-Wu Xu
It is an ongoing challenge to fabricate nonprecious oxygen reduction reaction (ORR) catalysts that can be comparable to or exceed the efficiency of platinum. A highly active non-platinum self-supporting Fe-N/C catalyst has been developed through the pyrolysis of a new type of precursor of iron coordination complex, in which 1,4-bis(1H-1,3,7,8-tetraazacyclopenta(1)phenanthren-2-yl)benzene (btcpb) functions as a ligand complexing Fe(II) ions. The optimal catalyst pyrolyzed at 700 °C (Fe-N/C-700) shows the best ORR activity with a half-wave potential (E1/2 ) of 840 mV versus reversible hydrogen electrode (RHE) in 0...
August 31, 2016: Small
Robert S Weatherup, Ashwin J Shahani, Zhu-Jun Wang, Ken Mingard, Andrew J Pollard, Marc-Georg Willinger, Robert Schloegl, Peter W Voorhees, Stephan Hofmann
The dynamics of graphene growth on polycrystalline Pt foils during chemical vapor deposition (CVD) are investigated using in situ scanning electron microscopy and complementary structural characterization of the catalyst with electron backscatter diffraction. A general growth model is outlined that considers precursor dissociation, mass transport, and attachment to the edge of a growing domain. We thereby analyze graphene growth dynamics at different length scales and reveal that the rate-limiting step varies throughout the process and across different regions of the catalyst surface, including different facets of an individual graphene domain...
September 7, 2016: Nano Letters
Haiyan Zheng, Kuo Li, George D Cody, Christopher A Tulk, Xiao Dong, Guoying Gao, Jamie J Molaison, Zhenxian Liu, Mikhail Feygenson, Wenge Yang, Ilia N Ivanov, Leonardo Basile, Juan-Carlos Idrobo, Malcolm Guthrie, Ho-Kwang Mao
Acetonitrile (CH3 CN) is the simplest and one of the most stable nitriles. Reactions usually occur on the C≡N triple bond, while the C-H bond is very inert and can only be activated by a very strong base or a metal catalyst. It is demonstrated that C-H bonds can be activated by the cyano group under high pressure, but at room temperature. The hydrogen atom transfers from the CH3 to CN along the CH⋅⋅⋅N hydrogen bond, which produces an amino group and initiates polymerization to form a dimer, 1D chain, and 2D nanoribbon with mixed sp(2) and sp(3) bonded carbon...
September 19, 2016: Angewandte Chemie
Srinivasa Rao Vaddipalli, Suresh Reddy Sanivarapu, Singaram Vengatesan, John Berchmans Lawrence, Malayappan Eashwar, Gosipathala Sreedhar
The electrochemical stability of MOFs in aqueous medium is most essential for MOFs based electrocatalysts for hydrogen production via water splitting. Since most MOFs suffer from instability issues in aqueous systems, there is enormous demand for electrochemically stable MOFs catalysts. Herein, we have developed a simple postsynthesis surface modification protocol for La (1,3,5-BTC) (H2O)6 metal-organic frameworks (LaBTC MOFs) using Mercaptopropionic acid (MPA), to attain electrochemical stability in aqueous mediums...
September 7, 2016: ACS Applied Materials & Interfaces
Xijia Yang, Haiming Sun, Lishu Zhang, Lijun Zhao, Jianshe Lian, Qing Jiang
A novel three-dimensional (3D) α-Fe2O3/MoS2 hierarchical nanoheterostructure is effectively synthesized via a facile hydrothermal method. The zero-dimensional (0D) Fe2O3 nanoparticles guide the growth of two-dimensional (2D) MoS2 nanosheets and formed 3D flower-like structures, while MoS2 facilitates the good dispersion of porous Fe2O3 with abundant oxygen vacancies. This charming 3D-structure with perfect match of non-equal dimension exhibits high recyclable photo-Fenton catalytic activity for Methyl orange pollutant and nice specific capacity in reusing as supercapacitor after catalysis...
2016: Scientific Reports
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"