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991.
Yincai Xu Chenglong Li Zhiqiang Li Qingyang Wang Xinliang Cai Jinbei Wei Yue Wang 《Angewandte Chemie (International ed. in English)》2020,59(40):17442-17446
The design and synthesis of organic materials with a narrow emission band in the longer wavelength region beyond 510 nm remain a great challenge. For constructing narrowband green emitters, we propose a unique molecular design strategy based on frontier molecular orbital engineering (FMOE), which can integrate the advantages of a twisted donor–acceptor (D‐A) structure and a multiple resonance (MR) delayed fluorescence skeleton. Attaching an auxiliary donor to a MR skeleton leads to a novel molecule with twisted D‐A and MR structure characteristics. Importantly, a remarkable red‐shift of the emission maximum and a narrowband spectrum are achieved simultaneously. The target molecule has been employed as an emitter to fabricate green organic light‐emitting diodes (OLEDs) with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23, 0.69) and a maximum external quantum efficiency (EQE) of 27.0 %. 相似文献
992.
993.
Felipe L. Oliveira Prof. Dr. Rodrigo B. Capaz Prof. Dr. Pierre M. Esteves 《Chemphyschem》2020,21(1):59-64
A structurally stable microporous metallic carbon allotrope, poly(spiro[2.2]penta-1,4-diyne) or, for short, spiro-carbon, with I41/amd (D4h) symmetry is predicted by first-principles calculations using density functional theory (DFT). The calculations of electronic, vibrational, and structural properties show that spiro-carbon has lower relative energy than other elusive carbon allotropes such as T-Carbon and 1-diamondyne (Y-Carbon). Its structure can be pictured as a set of trans-cisoid-polyacetylene chains tangled and interconnected together by sp3 carbon atoms. Calculations reveal a metallic electronic structure arising from an “intrinsic doping” of trans-cisoid-polyacetylene chains with sp3 carbon atoms. Possible synthetic routes and various simulated spectra (XRD, NMR, and IR absorption) are provided in order to guide future efforts to synthesize this novel material. 相似文献
994.
Morteza Rezaei Talarposhti Tristan Asset Samuel T. Garcia Yechuan Chen Sergio Herrera Sheng Dai Eric J. Peterson Kateryna Artyushkova Iryna Zenyuk Plamen Atanassov 《Chemphyschem》2020,21(12):1331-1339
We investigated the oxygen reduction reaction (ORR) mechanism on Pt nanoparticles (NPs) dispersed on several carbon blacks with various physicochemical properties (i. e. specific surface ranging from 80 to 900 m2 g−1, different graphitization degree, etc.). Using the kinetic isotope effect (KIE) along with various electrochemical characterizations, we determined that the rate determining step (RDS) of the ORR is a proton-independent step when the density of Pt NPs on the surface of the carbon support is high. Upon decrease of the density of Pt NPs on the surface, the RDS of the ORR starts involving a proton, as denoted by an increase of the KIE >1. This underlined the critical role played by the carbon support in the oxygen reduction reaction electrocatalysis by Pt supported on high surface area carbon. 相似文献
995.
Dr. Juliana Arriel Torres Dr. Gelson T. S. T. Da Silva Dr. Fernando Barbosa de Freitas Silva Dr. Caue Ribeiro 《Chemphyschem》2020,21(21):2392-2396
Tin dioxide (SnO2) has intrinsic characteristics that do not favor its photocatalytic activity. However, we evidenced that surface modification can positively influence its performance for CO2 photoreduction in the gas phase. The hydroxylation of the SnO2 surface played a role in the CO2 affinity decreasing its reduction potential. The results showed that a certain selectivity for methane (CH4), carbon monoxide (CO), and ethylene (C2H4) is related to different SnO2 hydrothermal annealing. The best performance was seen for SnO2 annealed at 150 °C, with a production of 20.4 μmol g−1 for CH4 and 16.45 μmol g−1 for CO, while for SnO2 at 200 °C the system produced more C2H4, probably due to a decrease of surface −OH groups. 相似文献
996.
Herman Maloko Loussala Sen Han Juanjuan Feng Min Sun Jiaqing Feng Jing Fan Meishan Pei 《Journal of separation science》2020,43(18):3655-3664
To enhance the extraction performance, a mesoporous silica was modified with ordered mesoporous carbon for solid‐phase microextraction. Three stainless‐steel wires coated with the mesoporous material were placed in a polyetheretherketone tube for getting an extraction tube. The tube was coupled to high‐performance liquid chromatography with diode array detector, and the online analysis system was constructed. Then its extraction performance was evaluated using hydrophobic polycyclic aromatic hydrocarbons, phthalates, and hydrophilic neonicotinoids. The best selectivity was presented for polycyclic aromatic hydrocarbons. Several main conditions were optimized such as sampling volume, sampling rate, methanol concentration in the sample, and desorption time, a rapid and sensitive analytical method was established toward polycyclic aromatic hydrocarbons. The analytical method exhibited wide linear range from 0.017 to 15 µg/L with acceptable correlation coefficients more than 0.9990, limits of detection in 0.005‐0.020 µg/L, limits of quantification ranging from 0.017 to 0.066 µg/L as well as large enrichment factors of 377‐2314. It was successfully applied to detect trace polycyclic aromatic hydrocarbons in some real water samples including tap water, snow water, and domestic sewage. 相似文献
997.
Fang Yuanxing Zheng Yun Fang Tao Chen Yong Zhu Yaodong Liang Qing Sheng Hua Li Zhaosheng Chen Chuncheng Wang Xinchen 《中国科学:化学(英文版)》2020,63(2):149-181
Photocatalysis,which is the catalyzation of redox reactions via the use of energy obtained from light sources,is a topic that has garnered a lot of attention in recent years as a means of addressing the environmental and economic issues plaguing society today.Of particular interest are photosynthesis can potentially mimic a variety of vital reactions,many of which hold the key to develop sustainable energy economy.In light of this,many of the technological and procedural advancements that have recently occurred in the field are discussed in this review,namely those linked to:(1)photocatalysts made from metal oxides,nitride,and sulfides;(2)photocatalysis via polymeric carbon nitride(PCN);and(3)general advances and mechanistic insights related to TiO2-based catalysts.The challenges and opportunities that have arisen over the past few years are discussed in detail.Basic concepts and experimental procedures which could be useful for eventually overcoming the problems associated with photocatalysis are presented herein. 相似文献
998.
Changchun Ji Guang Yang P. Robert Ilango Junnan Song Deshuang Yu Sujun Han Dongxing Zhang Linlin Li Shengjie Peng 《化学:亚洲杂志》2020,15(13):1957-1962
With the environmental pollution and non‐renewable fossil fuels, it is imperative to develop eco‐friendly, renewable, and highly efficient electrocatalysts for sustainable energy. Herein, a simple electrospinning process used to synthesis Mo2C‐embedded multichannel hollow carbon nanofibers (Mo2C‐MCNFs) and followed by the pyrolysis process. As prepared lotus root‐like nanoarchitecture could offer rich porosity and facilitate the electrolyte infiltration, the Mo2C‐MCNFs delivered favourable catalytic activity for HER and OER. The resultant catalysts exhibit low overpotentials of 114 mV and 320 mV at a current density of 10 mA cm?2 for HER and OER, respectively. Furthermore, using the Mo2C‐MCNFs catalysts as a bifunctional electrode toward overall water splitting, which only needs a small cell voltage of 1.68 V to afford a current density of 10 mA cm?2 in the home‐made alkaline electrolyzer. This interesting work presents a simple and effective strategy to further fabricating tunable nanostructures for energy‐related applications. 相似文献
999.
Jakkapan Kumsampao Chaiyon Chaiwai Pongsakorn Chasing Thanyarat Chawanpunyawat Supawadee Namuangruk Taweesak Sudyoadsuk Vinich Promarak 《化学:亚洲杂志》2020,15(19):3029-3036
Despite the success of thermally activated delayed fluorescent (TADF) materials in steering the next generation of organic light‐emitting diodes (OLEDs), effective near infrared (NIR) TADF emitters are still very rare. Here, we present a simple and extremely high electron‐deficient compound, 5,6‐dicyano[2,1,3]benzothiadiazole (CNBz), as a strong electron‐accepting unit to develop a sufficiently strong donor‐acceptor (D?A) interaction for NIR emission. End‐capping with the electron‐donating triphenylamine (TPA) unit created an effective D?A?D type system, giving rise to an efficient NIR TADF emissive molecule (λem=750 nm) with a very small ΔEST of 0.06 eV. The electroluminescent device using this NIR TADF emitter exhibited an excellent performance with a high maximum radiance of 10020 mW Sr?1 m?2, a maximum EQE of 6.57% and a peak wavelength of 712 nm. 相似文献
1000.
《Arabian Journal of Chemistry》2020,13(6):5878-5889
A novel biological approach is attempted to convert the human urinary waste into a well-designed bionanomaterial. In the present study, biological activated ammonia gas (NH3(g)) mediated synthesis of hydroxyapatite material (B-HAp) and then impregnation of silver nanoparticles (AgNPs) on the B-HAp material surface was performed by photoreduction method and was followed by an evaluation of its antibacterial activity and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. X-ray diffraction spectroscopy (XRD) and Field emission-scanning electron microscopy (FE-SEM) were engaged to analyze the synthesized materials. Analytical studies revealed the morphology of the crystalline B-HAp synthesized by biologically activated NH3(g) as spherical shaped with AgNPs impregnated on over it. Atomic Absorption Spectrometers (AAS) estimated 2–7 ppm of Ag+ ion were released from the 100 ppm of Ag concentration was impregnated with B-HAp material (B-HAp-Ag-10). It was also found to be an excellent performance of antibacterial activity against Pseudomonas sp, E.coli and S. aureus. The cell- material interaction study of the thus synthesised B-HAp-Ag-10 was found to exhibit a minimal cytotoxicity level when incorporated in MG63 osteosarcoma cell lines, thus confirming the prospective biological application of our material in the biomedical field. 相似文献