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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(36):10980-10984
CO2 electroreduction is a promising technique for satisfying both renewable energy storage and a negative carbon cycle. However, it remains a challenge to convert CO2 into C2 products with high efficiency and selectivity. Herein, we report a nitrogen‐doped ordered cylindrical mesoporous carbon as a robust metal‐free catalyst for CO2 electroreduction, enabling the efficient production of ethanol with nearly 100 % selectivity and high faradaic efficiency of 77 % at −0.56 V versus the reversible hydrogen electrode. Experiments and density functional theory calculations demonstrate that the synergetic effect of the nitrogen heteroatoms and the cylindrical channel configurations facilitate the dimerization of key CO* intermediates and the subsequent proton–electron transfers, resulting in superior electrocatalytic performance for synthesizing ethanol from CO2. 相似文献
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A nanocomposite of CdSe quantum dots with nitrogen‐doped carbon nanotubes was prepared for enhancing the electrochemiluminescent (ECL) emission of quantum dots. With hydrogen peroxide as co‐reactant, the nanocomposite modified electrode showed a cathodic ECL emission with a starting potential of ?0.97 V (vs. Ag/AgCl) in phosphate buffer solution, which was five‐times stronger than that from pure CdSe quantum dots and three‐times stronger than that from CdSe quantum dots composited with carbon nanotubes. The latter showed a starting potential of ?1.19 V. This result led to a sensitive ECL sensing of hydrogen peroxide with good stability, acceptable reproducibility and a detection limit down to 2.1×10?7 mol L?1. Nitrogen‐doped carbon nanotubes could be used as a good material for the construction of sensitive ECL biosensors for chemical and biochemical analysis. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(10):2657-2662
Repeating guest units of polyesters poly‐(R )‐ 2 were selectively encapsulated by capsule 1 (BF4)4 to produce supramolecular graft polymers. The encapsulation of the guest units was confirmed by 1H NMR spectroscopy. The graft polymer structures were confirmed by the increase in the hydrodynamic radii and the solution viscosities of the polyesters upon complexation of the capsule. After the capsule was formed, atomic force microscopy showed extension of the polyester chains. The introduction of the graft chains onto poly‐(R )‐ 2 resulted in the main chain of the polymer having an M ‐helical morphology. The complexation of copolymers poly‐[(R )‐ 2 ‐co ‐(S )‐ 2 ] by the capsule gave rise to the unique chiral amplification known as the majority‐rules effect. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(15):4234-4237
We report a rational synthesis of carbon nanodots (CNDs) aimed at tailoring their emission, starting from a reasoned choice of organic precursors. To showcase the potential of this approach in a field such as optoelectronics, we designed experiments aimed at preparing materials that emit across the entire visible spectrum. Specifically, using precursors such as arginine, ethylenediamine, naphthalene dianhydride, and 2,6‐dibromonaphtalene dianhydride, in appropriate ratios, it was possible to obtain pure white‐light (0.33, 0.33; CIE coordinates) emitting carbon nanodots (WCNDs) through a one‐step microwave‐assisted synthesis and facile purification. The characterization and properties of this novel nanomaterial is discussed. 相似文献
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Marco Carini Lei Shi Thomas W. Chamberlain Meng Liu Giovanni Valenti Manuel Melle‐Franco Francesco Paolucci Andrei N. Khlobystov Thomas Pichler Aurelio Mateo‐Alonso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(30):10382-10386
Controlled nitrogen‐doping is a powerful methodology to modify the properties of carbon nanostructures and produce functional materials for electrocatalysis, energy conversion and storage, and sensing, among others. Herein, we report a wall‐ and hybridisation‐selective synthetic methodology to produce double‐walled carbon nanotubes with an inner tube doped exclusively with graphitic sp2‐nitrogen atoms. Our measurements shed light on the fundamental properties of nitrogen‐doped nanocarbons opening the door for developing their potential applications. 相似文献
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Jin Xie Bo‐Quan Li Hong‐Jie Peng Yun‐Wei Song Jia‐Xing Li Ze‐Wen Zhang Qiang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5017-5021
The preparation of carbon materials usually involves the decomposition of precursors and the reorganization of the as‐generated fragments. However, the cleavage of bonds and the simultaneous formation of new bonds at nearly the same positions prevents effective yet precise fabrication. Herein, a supramolecular precursor, cucurbit[6]uril, that contains multiple bonds with distinct bond strengths is proposed to decouple the twin problem of simultaneous bond cleavage and formation, allowing multistage transformations to hierarchical porous carbon and metal‐doped carbon in a single yet effective pyrolysis step without the need of a template or additional purification. As a proof‐of‐concept, the Fe‐doped carbon electrocatalysts realized a Pt/C‐like half‐wave potential of 0.869 V vs. RHE and small Tafel slope of 51.3 mV dec?1 in oxygen reduction reaction. 相似文献
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Sibo Wang Yongjin Fang Xiao Wang Xiong Wen Lou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(3):770-773
The design and synthesis of hierarchical microboxes, assembled from SnS nanoplates coated with nitrogen‐doped carbon (NC) as an anode material for sodium‐ion batteries, is demonstrated. The template‐engaged multistep synthesis of the SnS@NC microboxes involves sequential phase transformation, polydopamine coating, and thermal annealing in N2. The SnS@NC composite with two‐dimensional nano‐sized subunits rationally integrates several advantages including shortening the diffusion path of electrons/Na+ ions, improving electric conductivity, and alleviating volume variation of the electrode material. As a result, the SnS@NC microboxes show efficient sodium storage performance with high capacity, good cycling stability, and excellent rate capability. 相似文献
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Multifunctional Nitrogen‐Doped Carbon Nanodots for Photoluminescence,Sensor, and Visible‐Light‐Induced H2 Production
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Dr. Pengju Yang Dr. Jianghong Zhao Dr. Jian Wang Dr. Huijuan Cui Li Li Prof. Dr. Zhenping Zhu 《Chemphyschem》2015,16(14):3058-3063
Herein, multifunctional N‐doped carbon nanodots (NCNDs) were prepared through the one‐step hydrothermal treatment of yeast. Results show that the NCNDs can be used as a new photocatalyst to drive the water‐splitting reaction under UV light. Moreover, the NCNDs can efficiently catalyze the hydrogen evolution reaction. Under visible‐light irradiation, Eosin Y‐sensitized NCNDs exhibit excellent activity for hydrogen evolution. The hydrogen evolution rate of NCNDs (without any modification and co‐catalyst) reaches 107.1 μmol h?1 (2142 μmol g?1 h?1). When Pt is loaded on the NCNDs, the hydrogen evolution rate reaches 491.2 μmol h?1 (9824 μmol g?1 h?1) under visible‐light irradiation. In addition, the NCNDs show excellent fluorescent properties and can be applied as a fluorescent probe for the sensitive and selective detection of Fe3+. 相似文献
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Zhengang Han Zhaofan Yang Heshui Sun Yali Xu Xiaofang Ma Duoliang Shan Jing Chen Shuhui Huo Zhen Zhang Peiyao Du Xiaoquan Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(18):5976-5980
Highly efficient detection in the aqueous phase for water‐insoluble organic molecule probes is challenging. The bright aggregated‐state electrochemiluminescence (ECL) of 1,1‐disubstituted 2,3,4,5‐tetraphenylsiloles by a co‐reactant approach was discovered, and a heterogeneous aggregation‐induced emission ECL (HAIE‐ECL) was constructed at the electrode surface, showing very high ECL efficiency (37.8 %) and selective recognition for industrially important DNBP plasticizer with a low detection limit of 0.15 nm in the water phase. A mechanistic study indicates that ECL is mainly generated due to the high electron affinity of siloles and restriction of the intramolecular motions caused by their propeller‐like noncoplanar structures. This system realizes the sensing of organic‐based ECL in the water phase by solving the crucial problems of water insolubility and aggregation‐caused quenching (ACQ), and demonstrates potential for further application because of its design and high efficiency. 相似文献
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Dr. Da‐Wei Wang Prof. Feng Li Dr. Li‐Chang Yin Xu Lu Dr. Zhi‐Gang Chen Prof. Ian R. Gentle Prof. Gao Qing Lu Prof. Hui‐Ming Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(17):5345-5351
A nitrogen‐doped porous carbon monolith was synthesized as a pseudo‐capacitive electrode for use in alkaline supercapacitors. Ammonia‐assisted carbonization was used to dope the surface with nitrogen heteroatoms in a way that replaced carbon atoms but kept the oxygen content constant. Ammonia treatment expanded the micropore size‐distributions and increased the specific surface area from 383 m2 g?1 to 679 m2 g?1. The nitrogen‐containing porous carbon material showed a higher capacitance (246 F g?1) in comparison with the nitrogen‐free one (186 F g?1). Ex situ electrochemical spectroscopy was used to investigate the evolution of the nitrogen‐containing functional groups on the surface of the N‐doped carbon electrodes in a three‐electrode cell. In addition, first‐principles calculations were explored regarding the electronic structures of different nitrogen groups to determine their relative redox potentials. We proposed possible redox reaction pathways based on the calculated redox affinity of different groups and surface analysis, which involved the reversible attachment/detachment of hydroxy groups between pyridone and pyridine. The oxidation of nitrogen atoms in pyridine was also suggested as a possible reaction pathway. 相似文献
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Nathaniel Z. Hardin Voj
Kocman Giacomo M. Di Mauro Thirupathi Ravula Ayyalusamy Ramamoorthy 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17406-17410
Paramagnetic relaxation enhancement (PRE) is commonly used to speed up spin lattice relaxation time (T1) for rapid data acquisition in NMR structural studies. Consequently, there is significant interest in novel paramagnetic labels for enhanced NMR studies on biomolecules. Herein, we report the synthesis and characterization of a modified poly(styrene‐co‐maleic acid) polymer which forms nanodiscs while showing the ability to chelate metal ions. Cu2+‐chelated nanodiscs are demonstrated to reduce the T1 of protons for both polymer and lipid‐nanodisc components. The chelated nanodiscs also decrease the proton T1 values for a water‐soluble DNA G‐quadruplex. These results suggest that polymer nanodiscs functionalized with paramagnetic tags can be used to speed‐up data acquisition from lipid bilayer samples and also to provide structural information from water‐soluble biomolecules. 相似文献
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Francesco Zinna Silvia Voci Lorenzo Arrico Elodie Brun Alexandre Homberg Laurent Bouffier Tiziana Funaioli Jrme Lacour Neso Sojic Lorenzo DiBari 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(21):7026-7030
The first observation of circular polarization of electrochemiluminescence (ECL) from a purely organic derivative is reported. A bispyrene scaffold mounted on a constrained polyether macrocycle displaying intense excimer fluorescence and highly circularly‐polarized (CP) photoluminescence has been selected for this purpose. The compound displays an ECL dissymmetry factor of about |8×10?3|, which is in good agreement with the corresponding photoluminescence value. This observation is the first step towards the molecular engineering of tailored dyes that can act as both ECL and CP‐ECL reporters for (bio)analysis by bringing a new level of information when dealing with chiral environments. Additionally, it provides an extra dimension to the ECL phenomenon and opens the way to chiral detection and discrimination. 相似文献
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Luca Schiaffino Gianfranco Ercolani 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2008,120(36):6938-6941
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Nitrogen‐Doped Porous Graphitic Carbon as an Excellent Electrode Material for Advanced Supercapacitors
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Dr. Li Sun Dr. Chungui Tian Yu Fu Dr. Ying Yang Dr. Jie Yin Dr. Lei Wang Prof. Honggang Fu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):564-574
An advanced supercapacitor material based on nitrogen‐doped porous graphitic carbon (NPGC) with high a surface area was synthesized by means of a simple coordination–pyrolysis combination process, in which tetraethyl orthosilicate (TEOS), nickel nitrate, and glucose were adopted as porogent, graphitic catalyst precursor, and carbon source, respectively. In addition, melamine was selected as a nitrogen source owing to its nitrogen‐enriched structure and the strong interaction between the amine groups and the glucose unit. A low‐temperature treatment resulted in the formation of a NPGC precursor by combination of the catalytic precursor, hydrolyzed TEOS, and the melamine–glucose unit. Following pyrolysis and removal of the catalyst and porogent, the NPGC material showed excellent electrical conductivity owing to its high crystallinity, a large Brunauer–Emmett–Teller surface area (SBET=1027 m2 g?1), and a high nitrogen level (7.72 wt %). The unusual microstructure of NPGC materials could provide electrochemical energy storage. The NPGC material, without the need for any conductive additives, showed excellent capacitive behavior (293 F g?1 at 1 A g?1), long‐term cycling stability, and high coulombic efficiency (>99.9 % over 5000 cycles) in KOH when used as an electrode. Notably, in a two‐electrode symmetric supercapacitor, NPGC energy densities as high as 8.1 and 47.5 Wh kg?1, at a high power density (10.5 kW kg?1), were achieved in 6 M KOH and 1 M Et4NBF4‐PC electrolytes, respectively. Thus, the synthesized NPGC material could be a highly promising electrode material for advanced supercapacitors and other conversion devices. 相似文献
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Three‐Dimensional Nitrogen‐Doped Hierarchical Porous Carbon as an Electrode for High‐Performance Supercapacitors
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Jing Tang Dr. Tao Wang Dr. Rahul R. Salunkhe Prof. Saad M. Alshehri Dr. Victor Malgras Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17293-17298
A facile and sustainable procedure for the synthesis of nitrogen‐doped hierarchical porous carbons with a three‐dimensional interconnected framework (NHPC‐3D) was developed. The strategy, based on a colloidal crystal‐templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self‐polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well‐preserved nitrogen doping after heat treatment. The obtained NHPC‐3D possesses a high surface area of 1056 m2 g?1, a large pore volume of 2.56 cm3 g?1, and a high nitrogen content of 8.2 wt %. The NHPC‐3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g?1 at a current density of 2 A g?1. The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g?1 in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion‐transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC‐3D as a promising candidate for electrode materials in supercapacitors. 相似文献