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https://www.readbyqxmd.com/read/29782677/ultrathin-transition-metal-dichalcogenide-3d-metal-hydroxide-hybridized-nanosheets-to-enhance-hydrogen-evolution-activity
#1
Zhengju Zhu, Huajie Yin, Chun-Ting He, Mohammad Al-Mamun, Porun Liu, Lixue Jiang, Yong Zhao, Yun Wang, Hua-Gui Yang, Zhiyong Tang, Dan Wang, Xiao-Ming Chen, Huijun Zhao
The vast majority of the reported hydrogen evolution reaction (HER) electrocatalysts perform poorly under alkaline conditions due to the sluggish water dissociation kinetics. Herein, a hybridization catalyst construction concept is presented to dramatically enhance the alkaline HER activities of catalysts based on 2D transition metal dichalcogenides (TMDs) (MoS2 and WS2 ). A series of ultrathin 2D-hybrids are synthesized via facile controllable growth of 3d metal (Ni, Co, Fe, Mn) hydroxides on the monolayer 2D-TMD nanosheets...
May 21, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29780484/exploiting-the-interactions-between-the-ruthenium-hoveyda-grubbs-catalyst-and-al-modified-mesoporous-silica-the-case-of-sba15-vs-kcc-1
#2
Baraa Werghi, Eva Pump, Mykyta Tretiakov, Edy Abou-Hamad, Andrei Gurinov, Pradeep Doggali, Dalaver H Anjum, Luigi Cavallo, Anissa Bendjeriou-Sedjerari, Jean-Marie Basset
Immobilization of the 2nd generation Hoveyda-Grubbs catalyst HG-II onto well-ordered 2D hexagonal (SBA15) and 3D fibrous (KCC-1) mesostructured silica, which contained tetra-coordinated Al, has been investigated through the Surface Organometallic Chemistry (SOMC) methodology. The main interest of this study lies in the peculiarity of the silica supports, which display a well-defined tetrahedral aluminum hydride site displaying a strong Lewis acid character, [( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-Si 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 )( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-)2 Al-H]...
April 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29765034/solvent-assisted-programming-of-flat-polymer-sheets-into-reconfigurable-and-self-healing-3d-structures
#3
Yang Yang, Eugene M Terentjev, Yen Wei, Yan Ji
It is extremely challenging, yet critically desirable to convert 2D plastic films into 3D structures without any assisting equipment. Taking the advantage of solvent-induced bond-exchange reaction and elastic-plastic transition, shape programming of flat vitrimer polymer sheets offers a new way to obtain 3D structures or topologies, which are hard for traditional molding to achieve. Here we show that such programming can be achieved with a pipette, a hair dryer, and a bottle of solvent. The polymer used here is very similar to the commercial epoxy, except that a small percentage of a specific catalyst is involved to facilitate the bond-exchange reaction...
May 15, 2018: Nature Communications
https://www.readbyqxmd.com/read/29736826/electrodes-modified-with-3d-graphene-composites-a-review-on-methods-for-preparation-properties-and-sensing-applications
#4
REVIEW
Nadeem Baig, Tawfik A Saleh
Three-dimensional (3D) porous networks of planar 2D graphene have attractive features with respect to sensing. These include a large electroactive surface area, good inner and outer surface contact with the analyte, ease of loading with (bio)catalysts, and good electrochemical sensitivity. 3D free-standing graphene can even be used directly as an electrode. This review (with 140 refs.) covers the progress made in the past years. Following an introduction into the field (including definitions), a large section is presented that covers methods for the synthesis of 3D graphene (3DG) (including chemical vapor deposition, hydrothermal methods, lithography, support assisted synthesis and chemical deposition, and direct electrochemical methods)...
May 7, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/29736509/solvent-dependent-variations-of-both-structure-and-catalytic-performance-in-three-manganese-coordination-polymers
#5
Xiao-Min Kang, Wen-Min Wang, Lin-Hong Yao, Hong-Xia Ren, Bin Zhao
Three new manganese 4'-(3,5-dicarboxyphenyl)-2,2':6',2'''-terpyridine (H2DATP) metal-organic framework materials have been generated through regulating the ratios of a binary solvent mixture (DMA/H2O) under solvothermal conditions. Compound 1 {[Mn2(DATP)(HDATP)(H2O)4](OH)·10H2O}n displaying a one-dimensional (1D) chainlike structure was crystallized from the DMA/H2O mixture with a molar ratio of 1 : 1, while the two-dimensional (2D) layer species, {[Mn(DATP)(H2O)]·2H2O}n (2) was produced by increasing the ratio of DMA/H2O to 5 : 1...
May 8, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29713706/co-oxide-nanostructures-for-electrocatalytic-water-oxidation-effects-of-dimensionality-and-related-properties
#6
S Gupta, A Yadav, S Bhartiya, M K Singh, A Miotello, A Sarkar, N Patel
A facile hydrothermal synthesis route was explored to obtain various nanostructures of Co oxide for applications in electrocatalytic water-splitting. The effect of reaction time and metal precursor ions on the morphology of synthesized nanostructures was studied in detail with the aid of a scanning electron microscope. By systematic optimization of the synthesis parameters, Co oxide nanostructures with single dimensionality were obtained in the form of 0D nanoparticles (NPs), 1D nanowires (NWs), 2D nanosheets (NSs) and 3D nanocrystals (NCs)...
May 10, 2018: Nanoscale
https://www.readbyqxmd.com/read/29708746/three-fold-intramolecular-ring-closing-alkene-metatheses-of-square-planar-complexes-with-cis-phosphorus-donor-ligands-p-x-ch-2-m-ch-ch-2-3-x-m-5-10-o-3-5-syntheses-structures-and-thermal-properties-of-macrocyclic-dibridgehead-diphosphorus-complexes
#7
Hemant Joshi, Sugam Kharel, Andreas Ehnbom, Katrin Skopek, Gisela D Hess, Tobias Fiedler, Frank Hampel, Nattamai Bhuvanesh, John A Gladysz
Reactions of cis-PtCl2 (P((CH2 ) m CH=CH2 )3 )2 and Grubbs' first generation catalyst and then hydrogenations afford cis-PtCl2 (P((CH2 ) n )3 P) ( cis-2; n = 2 m+2 = b/12, c/14, d/16, e/18, f/20, g/22; 6-40%), derived from three fold interligand metatheses. The phosphite complexes cis-PtCl2 (P(O(CH2 ) m* CH=CH2 )3 )2 are similarly converted to cis-PtCl2 (P(O(CH2 ) n* O)3 P) ( cis-5; n* = a/8, b/10, c/12, 10-20%). The substitution products cis-PtPh2 (P((CH2 ) n )3 P) ( cis-6c,d) and cis-PtI2 (P(O(CH2 )10 O)3 P) are prepared using Ph2 Zn and NaI, respectively...
April 30, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29700514/advanced-bi-functional-copi-co-catalyst-decorated-g-c-3-n-4-nanosheets-coupled-with-zno-nanorod-arrays-as-integrated-photoanodes
#8
Chang Liu, Pengcheng Wu, Keliang Wu, Guihua Meng, Jianning Wu, Juan Hou, Zhiyong Liu, Xuhong Guo
In this work, a CoPi-decorated type II heterojunction composed of one-dimensional (1D) ZnO nanorod arrays (NRAs) coated with two-dimensional (2D) carbon nitride (g-C3N4) was successfully prepared and used as photoanode. CoPi has been speculated to be a mixture of amorphous compound and two cobalt-based compounds: Co3(PO3)6·14H2O and Co(H2PO2)2·6H2O. The advanced bi-functional CoPi acts like a shelter, effectively inhibiting the photocorrosion of CNNS/ZnO NRAs and providing a faster hole transfer channel. Synergistic effects at the interface of the heterojunction efficiently improve the separation of charge carriers from photoexcited g-C3N4 nanosheets to the ZnO nanorods...
April 27, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29688695/two-dimensional-mos-2-confined-co-oh-2-electrocatalysts-for-hydrogen-evolution-in-alkaline-electrolytes
#9
Yuting Luo, Xu Li, Xingke Cai, Xiaolong Zou, Feiyu Kang, Hui-Ming Cheng, Bilu Liu
The development of abundant and cheap electrocatalysts for the hydrogen evolution reaction (HER) has attracted increasing attention over recent years. However, to achieve low-cost HER electrocatalysis, especially in alkaline media, is still a big challenge due to the sluggish water dissociation kinetics as well as the poor long-term stability of catalysts. In this paper we report the design and synthesis of a two-dimensional (2D) MoS2 confined Co(OH)2 nanoparticle electrocatalyst, which accelerates water dissociation and exhibits good durability in alkaline solutions, leading to significant improvement in HER performance...
April 24, 2018: ACS Nano
https://www.readbyqxmd.com/read/29683392/synthetic-polymannose-as-a-drug-carrier-synthesis-toxicity-and-anti-fungal-activity-of-polymannose-amphotericin-b-conjugates
#10
Arul Prakash Francis, Sneha Gurudevan, A Jayakrishnan
Polymannose (PM) having a weight-average molar mass (Mw ) of 30-53 kDa was synthesized by the polycondensation of mannose using phosphorous acid as the catalyst and characterized by various techniques such as NMR, IR, GPC and polarimetry. 2D NMR results confirmed the presence of (1→ 6)-linked α-D-mannose residues as backbone with O-3 and O-2 substituted linear or branched chains in PM. Amphotericin B (AmB) was conjugated to periodate-oxidized PM through Schiff's linkages at 20 wt% concentration. The AmB-PM conjugates were highly soluble in phosphate buffered saline (180-250 mg/mL), exhibited negligible hemolytic potential to human erythrocytes even at a concentration of 200 μg /mL (equivalent to ~ 40 μg/mL AmB) and were non-toxic to human embryonic kidney (HEK293T) cells even at a concentration of 250 μg/mL (equivalent to ~ 50 μg/mL AmB)...
April 23, 2018: Journal of Biomaterials Science. Polymer Edition
https://www.readbyqxmd.com/read/29629082/metal-organic-layers-stabilize-earth-abundant-metal-terpyridine-diradical-complexes-for-catalytic-c-h-activation
#11
Zekai Lin, Nathan C Thacker, Takahiro Sawano, Tasha Drake, Pengfei Ji, Guangxu Lan, Lingyun Cao, Shubin Liu, Cheng Wang, Wenbin Lin
We report the synthesis of a terpyridine-based metal-organic layer (TPY-MOL) and its metalation with CoCl2 and FeBr2 to afford CoCl2 ·TPY-MOL and FeBr2 ·TPY-MOL, respectively. Upon activation with NaEt3 BH, CoCl2 ·TPY-MOL catalyzed benzylic C-H borylation of methylarenes whereas FeBr2 ·TPY-MOL catalyzed intramolecular Csp3 -H amination of alkyl azides to afford pyrrolidines and piperidines. X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy, UV-Vis-NIR spectroscopy, and electron paramagnetic spectroscopy (EPR) measurements as well as density functional theory (DFT) calculations identified M(THF)2 ·TPY-MOL (M = Co or Fe) as the active catalyst with a MII -(TPY˙˙)2- electronic structure featuring divalent metals and TPY diradical dianions...
January 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/29622818/ultrathin-layered-double-hydroxide-nanosheets-with-ni-iii-active-species-obtained-by-exfoliation-for-highly-efficient-ethanol-electrooxidation
#12
Liang Xu, Zhe Wang, Xu Chen, Zongkai Qu, Feng Li, Wensheng Yang
The development of non-precious metal electrocatalysts for renewable energy conversion and storage is compelling but greatly challenging due to low activity of the existing catalysts. Herein, the ultrathin NiAl-layered double hydroxide nanosheets (NiAl-LDH-NSs) are prepared by simple liquid-exfoliation of bulk NiAl-LDHs and first used as ethanol electrooxidation catalysts. The ultrathin two-dimensional (2D) structure ensures that the LDH nanosheets expose a greater number of active sites. More importantly, much Ni(III) active species (NiOOH) in the ultrathin nanosheets are formed by the exfoliation process, which play an authentic catalytic role in the ethanol oxidation reaction (EOR)...
January 10, 2018: Electrochimica Acta
https://www.readbyqxmd.com/read/29619313/nickel-hydr-oxy-oxide-nanoparticles-on-metallic-mos-2-nanosheets-a-synergistic-electrocatalyst-for-hydrogen-evolution-reaction
#13
Xing Zhang, Yongye Liang
Molybdenum disulfide (MoS2 )-based materials have been recently identified as promising electrocatalysts for hydrogen evolution reaction (HER). However, little work has been done to improve the catalytic performance of MoS2 toward HER in alkaline electrolytes, which is more suitable for water splitting in large-scale applications. Here, it is reported that the hybridization of 0D nickel hydr(oxy)oxide nanoparticles with 2D metallic MoS2 nanosheets can significantly enhance the HER activities in alkaline and neutral electrolytes...
February 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://www.readbyqxmd.com/read/29616268/synthesis-of-single-crystalline-two-dimensional-transition-metal-phosphides-via-a-salt-templating-method
#14
Tianqi Li, Hongrun Jin, Zhun Liang, Liang Huang, Yucheng Lu, Huimin Yu, Zhimi Hu, Jiabin Wu, Bao Yu Xia, Guang Feng, Jun Zhou
Transition-metal phosphides (TMPs) are considered as promising non-noble electrochemical catalysts for hydrogen evolution reaction (HER). Their highly active sites are located on certain facets, and single crystalline two-dimensional (2D) structures enable them to expose the most active facets for HER. However, the synthesis of single crystalline 2D TMPs is still a challenge owing to their intrinsically non-layered structures. Herein, we demonstrate the synthesis of various single crystalline 2D TMPs (Co2P, MoP2, Ni12P5 and WP2) by a salt-templating method...
April 4, 2018: Nanoscale
https://www.readbyqxmd.com/read/29603430/diatomite-templated-synthesis-of-freestanding-3d-graphdiyne-for-energy-storage-and-catalysis-application
#15
Jiaqiang Li, Jing Xu, Ziqian Xie, Xin Gao, Jingyuan Zhou, Yan Xiong, Changguo Chen, Jin Zhang, Zhongfan Liu
Graphdiyne (GDY), a new kind of two-dimensional (2D) carbon allotropes, has extraordinary electrical, mechanical, and optical properties, leading to advanced applications in the fields of energy storage, photocatalysis, electrochemical catalysis, and sensors. However, almost all reported methods require metallic copper as a substrate, which severely limits their large-scale application because of the high cost and low specific surface area (SSA) of copper substrate. Here, freestanding three-dimensional GDY (3DGDY) is successfully prepared using naturally abundant and inexpensive diatomite as template...
March 30, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29594280/theoretical-study-on-the-origin-of-activity-for-the-oxygen-reduction-reaction-of-metal-doped-two-dimensional-boron-nitride-materials
#16
Chaofang Deng, Rongxing He, Dimao Wen, Wei Shen, Ming Li
Two-dimensional boron nitride (2D-BN) materials doped with metallic atoms are suitable candidates for the oxygen reduction reaction (ORR) to replace Pt-based catalysts. In this study, a series of model 2D-BN materials doped with metallic atoms were designed to uncover the relationship between ORR activity and metallic dopants. A volcano curve correlation was derived between ORR overpotential and the adsorption free energy values of *OH. Only the doped structures, located at the top of the volcano curve, exhibit optimized activity...
March 29, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29571138/mitigation-of-harmful-indoor-organic-vapors-using-plug-flow-unit-coated-with-2d-g-c-3-n-4-and-metallic-cu-dual-incorporated-1d-titania-heterostructure
#17
Dong Jin Kim, Wan-Kuen Jo
Herein, a plug-flow reactor coated with one-dimensional (1D) TiO2 nanotube (TNT) heterostructures incorporated with g-C3 N4 (CN) and metallic Cu (CN/Cu/TNT) nanocomposite and irradiated by a daylight lamp was newly applied for the mitigation of harmful indoor organic vapors. The CN/Cu/TNT catalyst showed high mitigation efficiency for all target pollutants, followed by Cu-incorporated TNT (Cu/TNT), CN-incorporated TNT (CN/TNT), TNT, and TiO2 , in that order. The order of their photocatalytic activities agrees with that of the electron‒hole separation rates determined from their photoluminescence emission spectra...
March 16, 2018: Chemosphere
https://www.readbyqxmd.com/read/29570191/design-of-iron-atom-modified-thiophene-linked-metalloporphyrin-2d-conjugated-microporous-polymer-as-co-2-reduction-photocatalyst
#18
Chongyang Chen, Chao Tang, Weiwei Xu, Youyong Li, Lai Xu
Herein, by means of density functional theory (DFT) calculations, we designed a new type of thiophene-linked porphyrin unit and incorporated it into an extended 2D conjugated microporous polymer (CMP) to serve as a CO2 reduction catalyst. This newly designed catalyst combines the advantages of molecular catalysis, heterogeneous catalysis, high structural stability and tunable electronic properties. A series of metal atoms (Fe, Mg, Mn, and Cu) were introduced into the center of the porphyrin ring to modify its capacity for reducing CO2...
March 23, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29566445/a-4-2-condensation-strategy-to-imine-linked-single-crystalline-zeolite-like-zinc-phosphate-frameworks
#19
Ritambhara Jangir, Alok Ch Kalita, Dhananjayan Kaleeswaran, Sandeep K Gupta, Ramaswamy Murugavel
Double-4-ring zinc phosphate (D4R), [Zn(dipp)(4-Py-CHO)]4 (2) (dipp=diiminopyridine), bearing four formyl groups, has been utilized as a building block (SBU) for the synthesis of a new class of imine-linked [4+2] COF-like polycrystalline zinc phosphate frameworks. Reactions of 2 with a series of linear aromatic diamines results in the formation of polycrystalline frameworks [Zn4 (dipp)4 (L)2 ]n (3-6) (L=L1 to L4 , diimines formed by condensation of 4-pyridine carboxaldehyde with diamines). Employing an alternative synthetic strategy, through a diffusion-controlled slow reaction of 2 with the pre-synthesized 4,4'-bispyridyl bisimine (L3 ), [Zn4 (dipp)4 (L3 )2 ]n (5') has been obtained as single crystals...
March 22, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29564430/spotting-the-differences-in-two-dimensional-materials-the-raman-scattering-perspective
#20
REVIEW
Shishu Zhang, Na Zhang, Yan Zhao, Ting Cheng, Xiaobo Li, Rui Feng, Hua Xu, Zhirong Liu, Jin Zhang, Lianming Tong
Two-dimensional (2D) layered materials have attracted tremendous attention and led to a prosperous development in both fundamental investigation and device applications in various fields, such as nanoelectronics, flexible devices, sustainable energy and catalysts. The precise characterization of the structure and properties of 2D materials is in urgent need. Raman scattering spectroscopy is one of the most popular characterization tools that is convenient, rapid and non-invasive. It provides information on both the lattice structure from the frequency of phonon modes and the electronic band structure through the intensity due to electronic resonance Raman scattering...
March 22, 2018: Chemical Society Reviews
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