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2D catalyst

Anamaria Todea, Diana Aparaschivei, Valentin Badea, Carmen G Boeriu, Francisc Peter
evelopments of past years placed the bio-based polyesters as competitive substitutes for fossil-based polymers. Moreover, enzymatic polymerization using lipase catalysts has become an important green alternative to chemical polymerization for the synthesis of polyesters with biomedical applications, as several drawbacks related to the presence of traces of metal catalysts, toxicity and higher temperatures could be avoided. Copolymerization of ε-caprolactone (CL) with four hydroxy-fatty acids (HFA) from renewable sources, e...
March 15, 2018: Biotechnology Journal
Nazan Kaloğlu, İsmail Özdemir, Nevin Gürbüz, Hakan Arslan, Pierre H Dixneuf
A series of new benzimidazolium halides were synthesized in good yields as unsymmetrical N -heterocyclic carbene (NHC) precursors containing the N-CH₂-arene group. The benzimidazolium halides were readily converted into ruthenium(II)-NHC complexes with the general formula [RuCl₂(η⁶,η¹-arene-CH₂-NHC)]. The structures of all new compounds were characterized by ¹H NMR (Nuclear Magnetic Resonance),13 C NMR, FT-IR (Fourier Transform Infrared) spectroscopy and elemental analysis techniques. The single crystal structure of one benzimidazole ruthenium complex, 2b , was determined...
March 13, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Ziwei Pan, Junnan Li, Kebin Zhou
Two-dimensional (2D) nanosheets with atomic thickness have attracted extensive research interests recently. In this work, atomically thin (0.7 nm) flat CdS (F-CdS) nanosheets with several tens of micrometer lateral size were synthesized by a solvent-thermal method. The as-synthesized F-CdS could maintain flat morphology well in solutions, while irreversible wrinkles could be generated after drying, forming the wrinkled CdS (W-CdS) samples. It was revealed that the formation of wrinkles could decrease the light absorbance, narrow the band gap, move down the conduction band position and accelerate electron-hole recombination...
March 7, 2018: Nanotechnology
Qing Xu, Yanping Tang, Xiaobin Zhang, Yoshifumi Oshima, Qiuhong Chen, Donglin Jiang
Progress over the past decades in porous materials has exerted great effect on the design of metal-free carbon electrochemical catalysts in fuel cells. The carbon material must combine three functions, i.e., electrical conductivity for electron transport, optimal pores for ion motion, and abundant heteroatom sites for catalysis. Here, an ideal carbon catalyst is achieved by combining two strategies-the use of a 2D covalent organic framework (COF) and the development of a suitable template to guide the pyrolysis...
March 5, 2018: Advanced Materials
Gustavo M Bosyk, Hector Freytes, Guido Bellomo, Giuseppe Sergioli
The transformation of an initial bipartite pure state into a target one by means of local operations and classical communication and entangled-assisted by a catalyst defines a partial order between probability vectors. This partial order, so-called trumping majorization, is based on tensor products and the majorization relation. Here, we aim to study order properties of trumping majorization. We show that the trumping majorization partial order is indeed a lattice for four dimensional probability vectors and two dimensional catalysts...
February 27, 2018: Scientific Reports
Raksha Dangol, Zhengfei Dai, Apoorva Chaturvedi, Yun Zheng, Yu Zhang, Khang Ngoc Dinh, Bing Li, Yun Zong, Qingyu Yan
The construction of two-dimensional (2D) ultrathin nanosheets is considered as a promising strategy for enhancing electrochemical performance, owing to their large surface area and fast electron transport. In this study, ultrathin few-layer NiPS3 nanosheets are obtained and systematically investigated by high-yield liquid phase exfoliation from their bulk layered crystals, and are exploited as anodes for lithium ion batteries (LIBs) and electrocatalysts for oxygen evolution reaction (OER). When evaluated as an anode for LIBs, NiPS3 nanosheets show excellent electrochemical properties in terms of stable cycling performance and rate capabilities...
February 26, 2018: Nanoscale
Esmail Doustkhah, Sadegh Rostamnia, Nao Tsunoji, Joel Henzie, Toshiaki Takei, Yusuke Yamauchi, Yusuke Ide
Enclosing functional nanoparticles in stable inorganic supports is important for generating ultra-stable catalytic active sites with good performance and material utilization efficiency. Here we describe a simple method to synthesize ultra-thin Ag nanocrystals with dimensions that are defined by the ∼1.4 nm 2D interlayer separating a layered silicate nanostructure. We call the particles "nanoplates" because they are <1.4 nm thick in one direction and their in-plane dimensions are defined by reaction time...
February 20, 2018: Chemical Communications: Chem Comm
Jakub Zimoch, Joan Simó Padial, Agnes S Klar, Queralt Vallmajo-Martin, Martin Meuli, Thomas Biedermann, Christopher J Wilson, Alan Rowan, Ernst Reichmann
Molecular and mechanical interactions with the 3D extracellular matrix are essential for cell functions such as survival, proliferation, migration, and differentiation. Thermo-responsive biomimetic polyisocyanopeptide (PIC) hydrogels are promising new candidates for 3D cell, tissue, and organ cultures. This is a synthetic, thermo-responsive and stress-stiffening material synthesized via polymerization of the corresponding monomers using a nickel perchlorate as a catalyst. It can be tailored to meet various demands of cells by modulating its stiffness and through the decoration of the polymer with short GRGDS peptides using copper free click chemistry...
February 14, 2018: Acta Biomaterialia
S Ramakrishnan, E J Jelmy, R Senthilkumar, Murali Rangarajan, Nikhil K Kothurkar
Bilayer and few layer-graphene (Gr) with noble metal (Ag and Au) and TiO2 nanoparticles were synthesized using atmospheric pressure radio frequency chemical vapor deposition (APRF-CVD). The precursors for the formation of the respective nanoparticles were dissolved in ethanol and injected into the APRF-CVD containing a Cu foil catalyst at 1000 °C. The graphene obtained had a blistered morphology similar to bubble-wrap. The bubble-like protrusions on the graphene sheet were caused by large nanoparticle clusters (~220 nm) formed below the graphene sheets...
February 1, 2018: Journal of Nanoscience and Nanotechnology
Jin-Lei Miao, Chuan-Bao Li, Hai-Hui Liu, Xing-Xiang Zhang
Formaldehyde (HCHO) is a main indoor pollutant that is capable of harming the health of residents. Here, we fabricated a novel MnO2/MWCNTs nanocomposite film for non-photocatalytic, room temperature removal of indoor HCHO. MnO2/MWCNTs nanocomposites with various amounts of a-MWCNTs, which were fabricated by a co-precipitation method, were assembled into composite films using vacuum filtration and solvent evaporation. Structural analysis confirms that MnO2 nanoparticles are homogeneously distributed on a-MWCNTs...
June 1, 2018: Journal of Nanoscience and Nanotechnology
Longtao Ma, Shengmei Chen, Zengxia Pei, Yan Huang, Guojin Liang, Funian Mo, Qi Yang, Jun Su, Yihua Gao, Juan Antonio Zapien, Chunyi Zhi
The exploitation of a high-efficient, low-cost and stable non-noble metal-based catalyst with oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) simultaneously, as air electrode material for rechargeable zinc-air battery is significantly crucial. Meanwhile, the compressible flexibility of a battery is the prerequisite of wearable or/and portable electronics. Herein, we present a strategy via single-site dispersing Fe-Nx species on a two dimensional (2D) highly-graphitic porous nitrogen-doped carbon layer to implement superior catalytic activity toward ORR/OER (with a half-wave potential of 0...
February 12, 2018: ACS Nano
Stephane Kenmoe, P Ulrich Biedermann
ZnO nanoparticles are used as catalysts and have potential applications in gas-sensing and solar energy conversion. A fundamental understanding of the exposed crystal facets, their surface chemistry, and stability as a function of environmental conditions is essential for rational design and improvement of synthesis and properties. We study the stability of water adsorbate phases on the non-polar low-index (101¯0) and (112¯0) surfaces from low coverage to multilayers using ab initio thermodynamics. We show that phonon contributions and the entropies due to a 2D lattice gas at low coverage and multiple adsorbate configurations at higher coverage have an important impact on the stability range of water adsorbate phases in the (T,p) phase diagram...
February 7, 2018: Journal of Chemical Physics
Masakazu Kuze, Hiroyuki Kitahata, Oliver Steinbock, Satoshi Nakata
Spatio-temporal oscillations confined to quasi-2D surface layers or 3D volumes play an important role for wave-induced information relay and global oscillations in living systems. Here, we describe experiments with the Belousov-Zhabotinsky reaction confined to microbeads in which the catalyst is selectively loaded either onto the surface or into the body of the spherical beads. We find that the dynamics of global oscillations, traveling reaction fronts, and rotating spiral waves under surface confinement are strikingly different from those in the bead volume...
February 8, 2018: Journal of Physical Chemistry. A
Sung In Jeong, Seong-Cheol Park, Sun-Jeong Park, Eun-Ji Kim, Hun Heo, Jong-Seok Park, Hui-Jeong Gwon, Youn-Mook Lim, Mi-Kyeong Jang
Introduction: Although numerous studies have been conducted with the aim of developing drug-delivery systems, chemically synthesized gene carriers have shown limited applications in the biomedical fields due to several problems, such as low-grafting yields, undesirable reactions, difficulties in controlling the reactions, and high-cost production owing to multi-step manufacturing processes. Materials and methods: We developed a 1-step synthesis process to produce 2-aminoethyl methacrylate-grafted water-soluble chitosan (AEMA-g-WSC) as a gene carrier, using gamma irradiation for simultaneous synthesis and sterilization, but no catalysts or photoinitiators...
2018: International Journal of Nanomedicine
Hong Li, Fei Ke, Junfa Zhu
The development of a highly efficient and stable bifunctional electrocatalyst for water splitting is still a challenging issue in obtaining clean and sustainable chemical fuels. Herein, a novel bifunctional catalyst consisting of 2D transition-metal phosphide nanosheets with abundant reactive sites templated by Co-centered metal-organic framework nanosheets, denoted as CoP-NS/C, has been developed through a facile one-step low-temperature phosphidation process. The as-prepared CoP-NS/C has large specific surface area and ultrathin nanosheets morphology providing rich catalytic active sites...
February 7, 2018: Nanomaterials
Bocheng Qiu, Mingyang Xing, Jinlong Zhang
Over the past few decades, two-dimensional graphene based materials (2DGMs) have piqued the interest of scientists worldwide, and the exploration of their potential applications in catalysis, sensors, electronic devices and energy storage due to their extraordinary physical and chemical properties has rapidly progressed. As for these 2DGMs, there is a complementary need to assemble 2D building blocks hierarchically into more complicated and hierarchical three-dimensional graphene-based materials (3DGMs). Such a capability is vitally crucial in order to design sophisticated and multi-functional catalysts with tailorable properties...
February 7, 2018: Chemical Society Reviews
Wenbei Zhang, Sai Sun, Lingyun Yang, Chenbao Lu, Yafei He, Chao Zhang, Ming Cai, Yefeng Yao, Fan Zhang, Xiaodong Zhuang
Porous carbon nanosheets and corresponding heteroatom doped porous carbon nanosheets have shown great potential as active materials for energy conversion and storage in recent years. However, it remains great challenge to prepare such kind of new two-dimensional (2D) polymer nanosheets without using any templates. In this work, thiadiazole-containing expanded heteroazaporphyrinoid was designed as the building blocks for preparation of free-standing N/S-containing polymer nanosheets (PN) without using any templates...
January 6, 2018: Journal of Colloid and Interface Science
Jinsuo Gao, Yanling Han, Jincheng Mu, Shouchun Wu, Feng Tan, Yong Shi, Xinyong Li
Employing nanocasting method, mesoporous MnO2 catalysts with large specific surface area and regular pore structure were synthesized by using three different types of mesostructure silicas (KIT-6, SBA-15, MCM-41) as hard templates. The physical and chemical properties of the three different mesostructured manganese oxide materials were comparatively and systematically characterized by using XRD, FT-IR, N2 adsorption-desorption, TEM, NH3-TPD, H2-TPR, XPS. The NH3-SCR performance of the mesoporous MnO2 was also evaluated on SCR self-assembly device...
January 16, 2018: Journal of Colloid and Interface Science
Chao Zhang, Xiaolong Zou, Zhiguo Du, Jianan Gu, Songmei Li, Bin Li, Shubin Yang
Although 2D nanocrystals with exposed high-energy facets are highly desired in the field of catalysts due to their anticipant high catalytic activities, they are difficult to be gained. Here, atomic layers of metallic molybdenum dioxide (MoO2 ) with primarily exposed high-energy (010) facet are achieved via a facile carbothermic reduction approach. The resultant MoO2 exhibits single-crystalline, monoclinic, and ultrathin features with nearly 100% exposed (010) facet, which can significantly reduce reaction barriers toward the oxygen reduction reaction...
February 6, 2018: Small
Yajun Zou, Jian-Wen Shi, Dandan Ma, Zhaoyang Fan, Linhao Cheng, Diankun Sun, Zeyan Wang, Chunming Niu
Two dimension/two dimension (2D/2D) stacking heterostructures are highly desirable in fabricating efficient photocatalysts because the face-to-face contact can provide maximized interfacial region between the two semiconductors, largely facilitating the migration of charge carriers. In this work, a novel WS2/g-C3N4 2D/2D nanosheet heterostructure decorated by CdS quantum dots (QDs) is reasonably designed for the first time. The optimized CdS/WS2/g-C3N4 without other co-catalyst exhibits a significantly enhanced photocatalytic H2 evolution rate of 1174...
February 4, 2018: ChemSusChem
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