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https://www.readbyqxmd.com/read/29136586/generalised-two-dimensional-correlation-analysis-of-the-co-ce-and-pd-mixed-oxide-catalytic-systems-for-methane-combustion-using-in-situ-infrared-spectroscopy
#1
Damian K Chlebda, Przemysław J Jodłowski, Roman J Jędrzejczyk, Joanna Łojewska
The process of methane combustion over the surface of a catalyst is still not fully understood. The identification of the reaction path and the intermediates created during catalysis is crucial for understanding the transformation of methane molecules. Two-dimensional (2D) correlation spectroscopy was engaged as a tool for the quantitative analysis of a series of temperature-dependent infrared spectra registered in situ during methane combustion. The prepared samples of catalysts were based on a Co, Pd and Ce mixed oxide adsorbed on an aluminium oxide layer deposited on kanthal steel...
November 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29124369/exploring-the-regioselectivity-in-the-cycloaddition-of-azides-to-alkynes-catalyzed-by-dinuclear-copper-clusters-cu2aac-reaction-using-the-topologies-of-%C3%A2-2-%C3%AF-r-and-%C3%A2-%C3%A2-2-%C3%AF-r
#2
S Calvo-Losada, J J Quirante
The regioselectivity of the dinuclear-Cu(I)-catalyzed version of the Huisgen reaction, abbreviated in this paper to Cu2AAC, was analyzed using quantum topological methods in order to study how the electronic charge distribution evolved along different reaction paths. Electronic densities were computed at the LC-wPBE/6-311++G(2d,2p)//LC-wPBE/6-311++G(d,p) level. The presence of two copper ions in the catalyst was found to lead to an electrophilic site in the external alkyne carbon that, in a generalized Sharpless-type mechanism, undergoes an initial donor-acceptor interaction with the azide molecule, but with an inverted electrophile-nucleophile pattern when compared with the corresponding mononuclear process (CuAAC)...
November 9, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/29105158/an-uncommon-carboxyl-decorated-mof-with-selective-gas-adsorption-and-catalytic-conversion-of-co2
#3
Lei Hou, Yong-Zhi Li, Hai-Hua Wang, Hong-Yun Yang, Yao-Yu Wang, Zhonghua Zhu
A new three-dimensional (3D) framework, [Ni(btzip)(H2btzip)]*2DMF*2H2O (1) (H2btzip = 4,6-bis(triazol-1-yl)isophthalic acid) as an acidic heterogeneous catalyst was constructed by the reaction of nickel wire and a triazolyl-carboxyl linker. 1 possesses intersected 2D channels decorated by free -COOH groups and uncoordinated triazoly N atoms, leading to not only high CO2 and C2H6 adsorption capacity but also significantly selective capture for CO2 and C2H6 over CH4 and CO in 273-333 K. Moreover, 1 reveals the chemical stability toward water...
November 3, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29079386/tailoring-the-self-assembly-of-linear-alkyl-chains-for-the-design-of-advanced-materials-with-technological-applications
#4
REVIEW
Cristina E Hoppe, Roberto J J Williams
The self-assembly of n-alkyl chains at the bulk or at the interface of different types of materials and substrates has been extensively studied in the past. The packing of alkyl chains is driven by Van der Waals interactions and can generate crystalline or disordered domains, at the bulk of the material, or self-assembled monolayers at an interface. This natural property of alkyl chains has been employed in recent years to develop a new generation of materials for technological applications. These studies are dispersed in a variety of journals...
October 13, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28992698/monitoring-of-heparin-activity-in-live-rats-using-metal-organic-framework-nanosheets-as-peroxidase-mimics
#5
Hanjun Cheng, Yufeng Liu, Yihui Hu, Yubin Ding, Shichao Lin, Wen Cao, Qian Wang, Jiangjiexing Wu, Faheem Muhammad, Xiaozhi Zhao, Dan Zhao, Zhe Li, Hang Xing, Hui Wei
Metal-organic framework (MOF) nanosheets are a class of two-dimensional (2D) porous and crystalline materials that hold promise for catalysis and biodetection. Although 2D MOF nanosheets have been utilized for in vitro assays, ways of engineering them into diagnostic tools for live animals are much less explored. In this work, a series of MOF nanosheets are successfully engineered into a highly sensitive and selective diagnostic platform for in vivo monitoring of heparin (Hep) activity. The iron-porphyrin derivative is selected as a ligand to synthesize a series of archetypical MOF nanosheets with intrinsic heme-like catalytic sites, mimicking peroxidase...
November 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28989686/electrochemical-maps-and-movies-of-the-hydrogen-evolution-reaction-on-natural-crystals-of-molybdenite-mos2-basal-vs-edge-plane-activity
#6
Cameron L Bentley, Minkyung Kang, Faduma M Maddar, Fengwang Li, Marc Walker, Jie Zhang, Patrick R Unwin
Two dimensional (2D) semiconductor materials, such as molybdenum disulfide (MoS2) have attracted considerable interest in a range of chemical and electrochemical applications, for example, as an abundant and low-cost alternative electrocatalyst to platinum for the hydrogen evolution reaction (HER). While it has been proposed that the edge plane of MoS2 possesses high catalytic activity for the HER relative to the "catalytically inert" basal plane, this conclusion has been drawn mainly from macroscale electrochemical (voltammetric) measurements, which reflect the "average" electrocatalytic behavior of complex electrode ensembles...
September 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28982086/conversion-of-levulinic-acid-into-alkyl-levulinates-using-lipase-immobilized-on-meso-molding-three-dimensional-macroporous-organosilica-as-catalyst
#7
Liya Zhou, Ying He, Li Ma, Yanjun Jiang, Zhihong Huang, Luyan Yin, Jing Gao
For conversion of biomass-derived levulinic acid into alkyl levulinates, a novel kind of lipase-based biocatalyst was prepared through immobilized lipase B from C. antarctica (CALB) on organosilica material with highly ordered 3D macroporous organosilica frameworks and a 2D hexagonal meso-structure (named 3DOM/m-OS) for the first time. The catalytic performance of the immobilized lipase (NER@3DOM/m-OS) was investigated. NER@3DOM/m-OS was used as biocatalyst to catalyze the esterification reaction between levulinic acid (LA) and n-butanol...
September 10, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28972738/controlling-water-intercalation-is-key-to-a-direct-graphene-transfer
#8
Ken Verguts, Koen Schouteden, Cheng-Han Wu, Lisanne Peters, Nandi Vrancken, Xiangyu Wu, Zhe Li, Maksiem Erkens, Clement Porret, Cedric Huyghebaert, Chris Van Haesendonck, Stefan De Gendt, Steven Brems
The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments, these steps remain very challenging, and transfer variations often result in unreliable 2D material properties. Here, it is demonstrated that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene. It is understood that interfacial water is essential for an electrochemistry-based graphene delamination from a Pt surface...
October 11, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28951557/electron-tomography-and-fractal-aspects-of-mos2-and-mos2-co-spheres
#9
Manuel Ramos, Félix Galindo-Hernández, Ilke Arslan, Toby Sanders, José Manuel Domínguez
A study was made by a combination of 3D electron tomography reconstruction methods and N2 adsorption for determining the fractal dimension for nanometric MoS2 and MoS2/Co catalyst particles. DFT methods including Neimarke-Kiselev's method allowed to determine the particle porosity and fractal arrays at the atomic scale for the S-Mo-S(Co) 2D- layers that conform the spherically shaped catalyst particles. A structural and textural correlation was sought by further characterization performed by x-ray Rietveld refinement and Radial Distribution Function (RDF) methods, electron density maps, computational density functional theory methods and nitrogen adsorption methods altogether, for studying the structural and textural features of spherical MoS2 and MoS2/Co particles...
September 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28949550/defect-induced-epitaxial-growth-for-efficient-solar-hydrogen-production
#10
Kan Zhang, Jung Kyu Kim, Bumsu Park, Shifeng Qian, Bingjun Jin, Xiaowei Sheng, Haibo Zeng, Hyunjung Shin, Sang Ho Oh, Chang-Lyoul Lee, Jong Hyeok Park
Epitaxial growth suffers from the mismatches in lattice and dangling bonds arising from different crystal structures or unit cell parameters. Here, we demonstrate the epitaxial growth of 2D MoS2 ribbon on 1D CdS nanowires (NWs) via surface and subsurface defects. The interstitial Cd(0) in the (12̅10) crystal plane of the [0001]-oriented CdS NWs are found to serve as nucleation sites for interatomically bonded [001]-oriented MoS2, where the perfect lattice match (∼99.7%) between the (101̅1) plane of CdS and the (002)-faceted in-plane MoS2 result in coaxial MoS2 ribbon/CdS NWs heterojunction...
October 6, 2017: Nano Letters
https://www.readbyqxmd.com/read/28940838/robust-catalysis-on-2d-materials-encapsulating-metals-concept-application-and-perspective
#11
REVIEW
Jiao Deng, Dehui Deng, Xinhe Bao
Great endeavors are undertaken to search for low-cost, rich-reserve, and highly efficient alternatives to replace precious-metal catalysts, in order to cut costs and improve the efficiency of catalysts in industry. However, one major problem in metal catalysts, especially nonprecious-metal catalysts, is their poor stability in real catalytic processes. Recently, a novel and promising strategy to construct 2D materials encapsulating nonprecious-metal catalysts has exhibited inimitable advantages toward catalysis, especially under harsh conditions (e...
September 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28937167/an-unsaturated-metal-site-promoted-approach-to-construct-strongly-coupled-noble-metal-hnb3o8-nanosheets-for-efficient-thermo-photo-catalytic-reduction
#12
Lijuan Shen, Yuzhou Xia, Sen Lin, Shijing Liang, Ling Wu
Creating two-dimensional (2D) crystal-metal heterostructures with an ultrathin thickness has spurred increasing research endeavors in catalysis because of its fascinating opportunities in tuning the electronic state at the surface and enhancing the chemical reactivity. Here we report a novel and facile Nb(4+)-assisted strategy for the in situ growth of highly dispersed Pd nanoparticles (NPs) on monolayer HNb3O8 nanosheets (HNb3O8 NS) constituting a 2D Pd/HNb3O8 NS heterostructure composite without using extra reducing agents and stabilizing agents...
October 5, 2017: Nanoscale
https://www.readbyqxmd.com/read/28933461/decoration-of-exfoliated-black-phosphorus-with-nickel-nanoparticles-and-its-application-in-catalysis
#13
Maria Caporali, Manuel Serrano-Ruiz, Francesca Telesio, Stefan Heun, Giuseppe Nicotra, Corrado Spinella, Maurizio Peruzzini
Nickel nanoparticles were dispersed on the surface of exfoliated black phosphorus and the resulting nanohybrid Ni/2DBP showed an improved stability with respect to pristine 2D BP when kept under ambient conditions in the dark. Ni/2DBP was applied as a catalyst in the semihydrogenation of phenylacetylene and exhibited high conversion and selectivity towards styrene. These features were preserved after recycling tests revealing the high stability of the nanohybrid.
October 3, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28921973/evans-showell-type-polyoxometalates-constructing-high-dimensional-inorganic-organic-hybrid-compounds-with-copper-organic-coordination-complexes-synthesis-and-oxidation-catalysis
#14
Haiyan An, Yujiao Hou, Lin Wang, Yumeng Zhang, Wei Yang, ShenZhen Chang
Four new hybrid architectures containing a [Co2Mo10H4O38](6-) polyoxoanion, (en)[Cu3(ptz)4(H2O)4][Co2Mo10H4O38]·24H2O (1), (Hbim)2[{Cu(bim)2(H2O)2}2{Co2Mo10H4O38}]·5H2O (2), H2[Cu(dpdo)3(H2O)4][{Cu2(dpdo)3(H2O)4(CH3CN)}2{Co2Mo10H4O38}2]·9H2O (3), and (H2bpp)4[{Cu(H2O)2}{NaCo2Mo10H4O38}2]·10H2O (4), where ptz = 5-(4-pyridyl)-1H-tetrazole, en = ethylenediamine, bim = benzimidazole, dpdo = 4,4'-bipyridine-N,N'-dioxide, and bpp = 1,3-bis(4-pyridyl)propane, have been prepared and characterized through elemental analysis, thermogravimetric analysis, IR spectroscopy, and powder and single-crystal X-ray diffraction...
October 2, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28915007/synthesis-and-properties-of-2d-carbon-graphdiyne
#15
Zhiyu Jia, Yongjun Li, Zicheng Zuo, Huibiao Liu, Changshui Huang, Yuliang Li
Graphdiyne (GDY) is a flat material comprising sp(2)- and sp-hybridized carbon atoms with high degrees of π conjugation that features uniformly distributed pores. It is interesting not only from a structural point of view but also from the perspective of its electronic, chemical, mechanical, and magnetic properties. We have developed an in situ homocoupling reaction of hexaethynylbenzene on Cu foil for the fabrication of large-area ordered films of graphdiyne. These films are uniform and composed of graphdiyne multilayers...
October 17, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28910096/finite-size-effects-in-submonolayer-catalysts-investigated-by-co-electrosorption-on-ptsml-pd-100
#16
Qiuyi Yuan, Hieu A Doan, Lars C Grabow, Stanko R Brankovic
A combination of scanning tunneling microscopy, subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS), and density functional theory (DFT) is used to quantify the local strain in 2D Pt clusters on the 100 facet of Pd and its effect on CO chemisorption. Good agreement between SNIFTIRS experiments and DFT simulations provide strong evidence that, in the absence of coherent strain between Pt and Pd, finite size effects introduce local compressive strain, which alters the chemisorption properties of the surface...
September 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28892617/understanding-of-electrochemical-mechanisms-for-co2-capture-and-conversion-into-hydrocarbon-fuels-in-transition-metal-carbides-mxenes
#17
Neng Li, Xingzhu Chen, Wee-Jun Ong, Douglas R MacFarlane, Xiujian Zhao, Anthony K Cheetham, Chenghua Sun
Two-dimensional (2D) transition-metal (groups IV, V, VI) carbides (MXenes) with formulas M3C2 have been investigated as CO2 conversion catalysts with well-resolved density functional theory calculations. While MXenes from the group IV to VI series have demonstrated an active behavior for the capture of CO2, the Cr3C2 and Mo3C2 MXenes exhibit the most promising CO2 to CH4 selective conversion capabilities. Our results predicted the formation of OCHO(•) and HOCO(•) radical species in the early hydrogenation steps through spontaneous reactions...
September 13, 2017: ACS Nano
https://www.readbyqxmd.com/read/28891263/superaerophobic-ultrathin-ni-mo-alloy-nanosheet-array-from-in-situ-topotactic-reduction-for-hydrogen-evolution-reaction
#18
Qian Zhang, Pengsong Li, Daojin Zhou, Zheng Chang, Yun Kuang, Xiaoming Sun
Hydrogen evolution reaction (HER) has prospect to becoming clean and renewable technology for hydrogen production and Ni-Mo alloy is among the best HER catalysts in alkaline electrolytes. Here, an in situ topotactic reduction method to synthesize ultrathin 2D Ni-Mo alloy nanosheets for electrocatalytic hydrogen evolution is reported. Due to its ultrathin structure and tailored composition, the as-synthesized Ni-Mo alloy shows an overpotential of 35 mV to reach a current density of 10 mA cm(-2) , along with a Tafel slope of 45 mV decade(-1) , demonstrating a comparable intrinsic activity to state-of-art commercial Pt/C catalyst...
September 11, 2017: Small
https://www.readbyqxmd.com/read/28880075/integrated-energy-aerogel-of-n-s-rgo-wse2-nife-ldh-for-both-energy-conversion-and-storage
#19
Xiaowei Xu, Hang Chu, Zhuqing Zhang, Pei Dong, Robert Baines, Pulickel M Ajayan, Jianfeng Shen, Mingxin Ye
High-performance active materials for energy-storage and energy-conversion applications require a novel class of electrodes: ones with a structure conducive to conductivity, large specific surface area, high porosity, and mechanical robustness. Herein, we report the design and fabrication of a new ternary hybrid aerogel. The process entails an in situ assembly of 2D WSe2 nanosheets and NiFe-LDH nanosheets on a 3D N,S-codoped graphene framework, accomplished by a facile hydrothermal method and electrostatic self-assembly technology...
September 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28876886/confined-catalysis-in-the-g-c3n4-pt-111-interface-feasible-molecule-intercalation-tunable-molecule-metal-interaction-and-enhanced-reaction-activity-of-co-oxidation
#20
Shujiao Wang, Yingxin Feng, Ming'an Yu, Qiang Wan, Sen Lin
The deposition of a two-dimensional (2D) atomic nanosheet on a metal surface has been considered as a new route for tuning the molecule-metal interaction and surface reactivity in terms of the confinement effect. In this work, we use first-principles calculations to systematically explore a novel nanospace constructed by placing a 2D graphitic carbon nitride (g-C3N4) nanosheet over a Pt(111) surface. The confined catalytic activity in this nanospace is investigated using CO oxidation as a model reaction. With the inherent triangular pores in the g-C3N4 overlayer being taken advantage of, molecules such as CO and O2 can diffuse to adsorb on the Pt(111) surface underneath the g-C3N4 overlayer...
September 27, 2017: ACS Applied Materials & Interfaces
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