MOLECULES
·
2023
·Vol. 28
·期 4
·1632
·
IF 4.6
Guozhu Ren,Danyang Zhang,Hao Wang,Xiaofang Li,Ruiping Deng,Shihong Zhou,Long Tian,Liang Zhou
The luminescent performances of near-infrared (NIR) lanthanide (Ln) complexes were restricted greatly by vibration quenching of X-H (X = C, N, O) oscillators, which are usually contained in ligands and solvents. Encapsulating Ln3+into a cavity of coordination atoms is a feasible method of alleviating this quenching effect. In this work, a novel ytterbium complex [Yb(DPPDA)2](DIPEA) coordinated with 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid (DPPDA) was synthesized and characterized by FT-IR, ESI-MS and elemental analysis. Under the excitation of 335 nm light, [Yb(DPPDA)2](DIPEA) showed two emission peaks at 975 and 1011 nm, respectively, which were assigned to the characteristic2F5/2→2F7/2transition of Yb3+. Meanwhile, this ytterbium complex exhibited a plausible absolute quantum yield of 0.46% and a luminescent lifetime of 105 μs in CD3OD solution. In particular, its intrinsic quantum yield was calculated to be 12.5%, and this considerably high value was attributed to the near-zero solvent molecules bound to Yb3+and the absence of X-H oscillators in the first coordination sphere. Based on experimental results, we further proposed that the sensitized luminescence of [Yb(DPPDA)2](DIPEA) occurred via an internal redox mechanism instead of an energy transfer process.Keywords:ytterbium complex;near-infrared luminescence;absolute quantum yield;luminescent lifetime;intrinsic quantum yield;internal redox mechanism
研究领域:
无机化学
·
材料科学
·
光学材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2022
·
IF 3.754
Shaofeng Liang,Muqun Wang,Wei Gao,Xia Zhao
Hydrothermal methods are commonly used to synthesize carbon dots (CDs), but the synthesized CDs have the disadvantage of low quantum yields. In this paper, we used acid treatment, elemental doping, and passivation to treat the CDs, which could increase the quantum yield from 36% to 42%, 61% and 68%, respectively, and the doping and passivation treatments resulted in red-shifted and blue-shifted emission behavior of the CDs. The optical properties , morphology and chemical structure of CDs are analyzed to investigate the reasons for the quantum yield increase and the mechanism of excitation dependent emission (EDE) and excitation independent emission (EIE). The increase of quantum yield is mainly due to the increase of pyridine N content. The different optical behaviors depend mainly on the surface states of CDs. C–OH and C–O–C can create new energy levels leading to the appearance of EDE properties. C=O is an electron-absorbing group that weakens the conjugation effect leading to blue shift.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Junhao Lin,Jiaman Sun,Yi Chen,Juan Luo,Chongwei Cui,Shichang Sun
To directionally convert sludge into the high-quality syngas, the effects of various parameters on the biogas produced by the sludge microwave pyrolysis are explored, and the syngas generation mechanism under the synergistic effect of parameters is revealed. The results showed that the pyrolysis final temperature, reaction time, and the amount of the microwave absorber were the key factors that affected the biogas yield. A response surface analysis was used to explore the synergistic effect of each key parameter on the yield and the lower heating vale (LHV) of syngas. The pyrolysis temperature was the key to driving syngas generation. Properly prolonging the reaction time decreased the formation of tar by-products and increased the syngas yield. The addition of a microwave absorber increased the heating rate by enhancing the conversion efficiency of microwave energy, and this contributed to accelerating the dehydrogenation and the Boudouard reactions to promote the generation of H 2 and CO. Under high temperature conditions (900 °C), a higher syngas yield (10.25–34.31 mol/kg DS ) and LHV (4.85–14.53 MJ/kg DS ) were obtained in a shorter period time by synergistically optimizing the amount of microwave absorbers (8–10 g) and the reaction time (28–40 min). As the pyrolysis temperature increased, the H 2 content gradually rose to the peak, while the content of CO continued to increase. By analyzing the evolution of the specific pyrolysis products, the secondary pyrolysis of bio-oil at high temperatures and the Boudouard reaction were found to be the primary pathways that promoted syngas generation. This research provides strategic guidance for producing high-quality syngas using the microwave pyrolysis of waste biomass, thereby minimizing the exploration cost of basic experiments and providing directional control of the syngas quality.
研究领域:
环境科学
·
能源工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2025
·
IF 3.9
Zhiming Ding,Danfeng Wang,Gang Wang,Runjuan Du,Chuanting Fan,Yaheng Zhang,Jie Zhang,Zhiyong Tang
Electrophotocatalysis, a burgeoning and sustainable technique in the field of organic synthesis, faces challenges in practical implementation due to technological and equipment limitations. This work introduces the design and engineering of an electrophotocatalytic flow microreactor for efficient synthesis of phenol from benzene in one step. The study explored the effects of microreactor configuration and various parameters, such as applied voltage, light intensity, and the concentrations of oxidant DDQ and electrolyte TBABF4. The innovative microreactor, characterized by a compact electrode gap and an expansive optical window, achieved a high phenol yield of 21.2% within a short residence time of 10 min, a significant improvement over the 14.3% yield obtained by a batch reactor in 6 h. The microreactor delivered a remarkable phenol productivity of 116.8 mmol h–1 L–1, outperforming all previous electrophotocatalytic synthesis records. Furthermore, a techno-economic analysis demonstrated that small-scale electrophotocatalytic synthesis of phenol reduced the per-unit production cost, displaying economic advantages competitive with the traditional cumene method. This work provides valuable insights into the engineering of flow microreactors for electrophotocatalysis and offers guidance for the potential industrial-scale application of electrophotocatalytic flow reactions.
研究领域:
有机合成
·
化学工程
·
可持续技术
✓ 已验证
产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2016
·
IF 1.045
Fengyi Wang,Zhixiong Huang,Guangwu Zhang,Yunxia Li
This work reports a boron- and silicon-containing phenolic-formaldehyde (PF) resin exhibiting an extremely high thermal decomposition temperature and char yield and formed by copolymerizing phenol, formaldehyde, boric acid (BA), and phenyltriethoxysilane (PTES). The structure of BA and PTES-modified PF (BSPF) resin was characterized by Fourier transform infrared spectroscopy. Thermal stability of the investigated composites was estimated by means of thermogravimetric analysis (TGA). The results of TGA indicated that the modified resin exhibited excellent thermal stability. Specifically, the thermoset had a char yield of 77.0% when the boron and silicon contents were only 1.27 wt% and 1.7 wt%, respectively. Compared with the unmodified resin (PF), the temperature at the maximum decomposing rate of the BSPF increased by 84°C and its charring yield was enhanced by 15.0%. The cured products of PF and BSPF were further investigated by X-ray diffraction and Raman spectroscopy, respectively. The incorporation of boron and silicon into the carbon lattice results in a decrease of interlayer spacing, and Raman ID/IG values for PF and BSPF (2.63 and 1.32) show that the rearrangement of crystalline structure leads to an increase in graphite structure and a decrease in disordered structure upon the modification processes.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 47
·13013-13022
·
IF 5.976
Dong Lu,Yiping Tang,Jinwei Gao,Qianming Wang
In contrast to conventional nanomaterials or organic dyes, carbon dots possess a variety of appealing properties including chemical inertness and easy manipulation and they can be dispersed in water. Herein, the use of a concentrated solar irradiation sintering strategy for the rapid and efficient assembly of carbon dots (CDs) has been reported for the first time. This novel alternative pathway effectively uses a renewable source and the process is feasible and environmentally sustainable. Three kinds of CDs were obtained, which demonstrate blue, green and red luminescence. Highly efficient blue-emitting CDs with quantum yield as high as 81% have been realized. The blue and red carbon dots give rise to excitation-independent emission peaks at 443 and 592 nm, respectively; however, the green CDs feature a continuous shift and the evolution of emission curves varies from 480 to 538 nm. By regulating the composition and ratios of these tri-color carbon dots, the emission band generates peaks from blue to red light, which cover almost the entire visible light range. Upon a single ultra-violet excitation at 365 nm, a white-light emission with CIE coordinates of (0.28, 0.33) was detected and the signal was very close to pure white light (0.33, 0.33). This study introduces a new method for fabricating low-cost nanoparticles as potential phosphors for light-emitting uses.
研究领域:
材料科学
·
环境科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 30
·9167-9174
·
IF 6.641
Chong Li,Baojun Ding,Lijing Zhang,Kepeng Song,Shengyang Tao
Organometal halide perovskite nanocrystals have received extensive attention as a high-performance photoelectric conversion material. However, the perovskite nanocrystals prepared by the traditional batch reactor have uncontrollable size and optical properties, low utilization of raw materials, and complicated purification treatment. In this paper, a flow microreactor is designed with the assistance of finite element analysis and realized the continuous synthesis of CH3NH3PbX3 nanocrystals with a 100% yield. The average size of the prepared nanocrystalline grains is as low as 3.9 nm without any purification step. The prepared nanocrystals have narrow-band emission characteristics (the full width at half-maximum is down to 18 nm), and the quantum yield can reach 76.9%. It is also possible to prepare CH3NH3PbX3 (X = Br, I) nanocrystals covering different emission wavelengths in the visible light region by this method. The coating of a polystyrene film improved the stability of the perovskite nanocrystals. The flexible hybrid film is applied to modify a LED device, and a white LED luminescence spectrum is obtained.
研究领域:
材料科学
·
纳米技术
·
光电子学
·
化学工程
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·
IF 2.7
Yulong Cui,Wenxuan Sun,Yao Dong,Yingnan Jiang,Jie Zhang,Tong Zhao,Jing Zhang,Yankai Wang,Meiling Sun,Guangchao Yin
The afterglow material based on carbon dots (CDs), with boric acid (BA) serving as the matrix, demonstrates outstanding structural rigidity. The covalent bond structure is particularly advantageous for stabilizing the triplet states of CDs, thus shielding the triplet excitons from quenching. Urea, on the other hand, harbors numerous CO and –NH2 functional groups, fostering the creation of hydrogen bond structures with CDs. This impedes the non-radiative recombination of CDs, thereby enhancing the production of afterglow. Here, we blend two substrate materials with distinct structural characteristics, utilizing their combined effect on restricting CDs. By employing this method, we have successfully synthesized afterglow materials with an exceptional absolute quantum yield (QY) of 61.22% and an afterglow delay time surpassing 5 s. Urea is employed to modulate the size and graphitization degree of CDs, thereby adjusting the emission wavelength in both solid state fluorescence (S-FL) and afterglow within composite materials. Furthermore, by adjusting the mixed ratio of BA and urea, thus altering their respective proportions in interacting with CDs, the brightness of S-FL and the delay time of afterglow are adjusted.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2019
·Vol. 11
·期 13
·5998-6003
·
IF 6.97
Dongjun Shen,Yijuan Long,Jie Wang,Yuanyuan Yu,Jiangli Pi,Lili Yang,Huzhi Zheng
A reduction pathway was developed to tune the fluorescence quantum yield (QY) and emission wavelength of carbon dots (CDs). Reducing the original CDs (QY ca. 1.55%, maximum emission ca. 520 nm) with NaBH4 increased QY to 7.25% and blue-shifted the maximum emission to 450 nm. Treating the original CDs with LiAlH4 increased QY to ca. 7.44% and blue-shifted the maximum emission to 345 nm. The distinct fluorescence characteristics of the original CDs, NaBH4-treated CDs, and LiAlH4-treated CDs were conferred by their differing surface groups. Moreover, the original CDs, NaBH4-treated CDs, and LiAlH4-treated CDs responded differently to a specific oxidizer of hydroxyl groups. The increase in the fluorescence QY and blue-shift of the emission wavelength were explained. This study provides a foundation for the preparation and tuning of CDs with excellent fluorescence performance, as well as for the development CD-based fluorescent probes.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2020
·Vol. 12
·期 2
·310
·
IF 3.426
Biwei Qiu,Jingyun Wang,Zhoujing Li,Xia Wang,Xiaoyan Li
Polyaniline (PANI), a typical conducting polymer, has attracted great interest as an electrode material. A series of PANIs were prepared through fast microwave-assisted chemical oxidative polymerization with varying HCl and APS concentrations here. It was found that the microwave synthesized PANIs had ~4 times higher for the yields and 7~10 times higher for the electrical conductivity in comparison to PANI samples prepared using conventional method. PANI nanosheets could easily be fabricated in weakly acidic solution due to their oligomeric structure, which contained flat phenazine rings. By contrast, linear PANI chains produced in highly acidic solutions formed nanofibers. The APS concentration did not significantly affect the molecular structures of PANIs under the conditions here. However, increasing the concentration of APS produced nanofibers with shorter branches, which may be due to secondary nucleation during chain growth resulting from increases in active initiation centers. The electrical conductivity and electrochemical performance of PANIs were both improved with increasing HCl and APS concentrations. Improvements due to increases in HCl concentration may be attributed to additions in conjugation length and enrichment of doping levels, while improvements due to increases in APS concentration could be attributed to the increased crystallinity of PANI, which facilitates ion transport.Keywords:microwave;polyaniline;yield;nanostructure;electrochemical
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMASS & BIOENERGY
·
2022
·
IF 5.774
Bang Yao,Qinhao Kang,Jie Fu,Yang Liu,Wenya Ao,Long Wang,Zhihui Jiang,Tianhao Zhang,Yongmeng Song,Zeyu Deng,Asif Ali Siyal,Jianjun Dai
Experiments were carried out to investigate cellulose and furfural from catalytic hydrolysis of corncob. This process improved the comprehensive utilization of hemicellulose and cellulose in biomass resources. Influence of factors (temperature, reaction time, concentration of catalysts, liquid to solid ratio (LSR)) on hydrothermal characteristics, furfural yield, properties and retention of cellulose were investigated through orthogonal and parameter tests. Acetic acid (6 wt%) and FeCl 3 (40 mM) achieved the highest furfural yield (47.60%) and relatively high cellulose retention ratio (71.84%) at 180 °C, 45 min, and 3 mL/g of LSR. While AlCl 3 and citric acid obtained low furfural yield and the lowest cellulose retention ratio (8.38%). Furfural was dominant in distillated organics (GC-MS areas ≥97.9%), by contrast furfural, 5-hydroxymethyfurfural and vanillin were main organics in residual liquors. The peak of furfural yield switched to shorter reaction time as temperature increased. Combination of AlCl 3 with acetic acid and citric acid accelerated cellulose degradation. NaCl inhibited furfural yield and promoted lignin decomposition. Higher temperature and greater concentration of FeCl 3 contributed to reduced crystallinity of cellulose during hydrothermal treatment.
研究领域:
生物化学
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2023
·
IF 4.3
Shihua Liao,Xiang Long,Yanshun Ma,Shaogui Wu,Jiayang Wang
Multicolor fluorescent carbon dots (CDs) have wide application prospects in many fields. Presented herein reported a synthesis of multicolor fluorescent CDs using zanthoxylum bungeanum as a carbon precursor. By changing the nitrogen sources, blue, green, and red fluorescent carbon dots (B-CDs, G-CDs, and R-CDs) with stable optical properties and high quantum yields (QY) were synthesized. Their emission wavelengths are 492 nm, 523 nm, and 601 nm respectively and their QYs were measured to be 13.1%, 11.2%, and 9.8%, respectively. These CDs exhibit good salt resistance, photobleaching resistance, and chemical stability. These characteristics make them suitable for various applications, particularly in the field of anti-counterfeiting fluorescent ink. This study provides an economic and efficient strategy for synthesizing multicolor fluorescent CDs derived from natural products, highlighting the potential for producing multicolor CDs and enhancing their application value.
研究领域:
材料科学
·
化学
·
植物学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）