MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 222
·期 10
·2000418
·
IF 2.527
Haoting Zheng,Kun Wu,Weilong Chen,Bingfei Nan,Zhencai Qu,Mangeng Lu
A series of copolymers of poly3-alkylthiophene (PTm) with different side chain lengths and copolymers of 3-butylthiophene and 3-butoxythiophene (PTDx) with different ratios are synthesized by oxidative polymerization. As the length of the side chain decreases, WAXD patterns of PTm show an increase in crystallinity. An increment of 50% in thermal conductivity is observed and the maximum thermal conductivity reaches to 0.320 Wm –1 K –1 . For PTDx, as the proportion of 3-butoxythiophene increases, the UV spectrum appears red-shifted, indicating an enhanced degree of p-π conjugation. The thermal conductivity of PTDx is increased from 0.340 to 0.374 Wm –1 K –1 , which is around twice that of traditional thermoplastics. Molecular dynamics (MD) is used to simulate the changes in the volume and dihedral angle overlap of the polymer at different temperatures, and achieves the same result as the experiment. MD simulations and experimental measurements have shown that reducing steric hindrance and enhancing p-π conjugation can increase the thermal conductivity of the polymer. Young's modulus of PTDx (around 1.86 GPa) is lower than that of conventional plastics, and its flexibility makes it more versatile.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Zihuan Wei,Lina Kong,Qiang Wang,Jianping Xu,Lan Li
Conjugated structure modification is an effective strategy for improving the photocatalytic activity of graphitic carbon nitride (g-C 3 N 4 ). Herein, we introduce p-π conjugated to g-C 3 N 4 by surface grafting of hydroxyl (-OH) groups through a facile hydrothermal process to improve the photo-carriers generation and separation. Experiments and DFT calculations indicate that the hydrothermal treatment decorated –OH groups onto the C sites of g-C 3 N 4 and formed p-π conjugated structure between the 2p orbitals of the O and the π orbitals of the tri-s-triazine unit. The extended p-π electrons delocalization of g-C 3 N 4 increases the concentration of the carriers, and the –OH groups serve as electrons transport channels facilitating the separation of the carriers. Consequently, –OH grafted g-C 3 N 4 with hydrothermal treated at 120 °C exhibits the highest and recyclable H 2 evolution rates of 2.3 mmol h −1 g −1 under simulated sunlight irradiation, which outperform pristine g-C 3 N 4 1.42 times. This work proposes a new mechanism of the p-π conjugate of –OH decorated g-C 3 N 4 for improving charge carriers formation and separation, and provides a mild strategy to engineer the other conjugated molecular structures.
研究领域:
材料科学
·
光催化
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 47
·22335-22343
·
IF 3.591
Siqi Wei,Haoyi Li,Xinghang Yin,Qiang Yang,Anli Chen,Renjie Li,Jing Wang,Rui Yang
Synthesizing high-efficiency red carbon dots (R-CDs) and exploring their photoluminescence mechanism remain challenges as well as critical issues hindering the development of red room-temperature phosphorescence (RTP) materials of CDs. Herein, a series of highly efficient R-CDs are prepared from citric acid and formamide by solvothermal method on account of the protective and destructive effects of solvents. The larger sp2 conjugated domains of the carbon core and the high content of graphitic N are identified as the key factors for R-CDs to exhibit red fluorescence. Surface groups also contribute to red emission by means of the formation of the N, O-related defect state. By establishing N-doping models and using DFT calculation, it is further demonstrated that the strong p–π conjugation effect caused by the non-bonding electrons of graphitic N would facilitate HOMO–LUMO splitting of the carbon core, thus leading to a significant decrease in the HOMO–LUMO gap. Energy level splitting could lead to a certain degree of energy level crossing, which could contribute to effective intersystem crossing and produce red RTP. From this, the potential applications of R-CDs in the information encryption field are proposed and demonstrated.
研究领域:
材料科学
·
光电技术
·
纳米技术
·
化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Qingqing Liu,Lan Zhou,Yuhua Zeng,Qiaolan Fang,Xing Deng,Wenzhou Zhong,Liqiu Mao
Developing low-cost and efficient metal-free carbon-based photocatalysts is of great significance but remains a challenge for light-driven selective organic synthesis integrated with CO 2 reduction. Herein, the N/O functional groups and high specific surface areas of porous biochars are dexterously designed by one-pot pyrolysis of waste coconut shell with combining tripolycyanamide and K 2 CO 3 co-modification, and demonstrate the high performance of the obtained porous biomass-derived biochar photocatalysts with photogenerated holes and electrons on the synergistic coupling amine dehydrogenation oxidation and reaction of CO 2 reduction to HCOOH, which can swiftly convert 86.0 % of benzylamine into N-benzylidenebenzylamine with a selectivity of 99.9 % under visible-light radiation. This coconut shell-derived biochar exhibits a wide generality for various aromatic amines, accompanied by the advantages of good recyclability and stability. Structure analysis and theoretical calculations reveal that the construction of the orbital interaction between the p-orbital on nitrogen and π-orbitals of polyaromatics with the terminal carboxylic acid groups greatly boosts the photogenerated charge-carrier separation, and reduce the possibility of recombination of photogenerated electrons and holes along with the layered graphitic structure. Meanwhile, the polyaromatic carboxylic acid groups and graphitic-N moieties serve as active sites with the π-π electron-donor-acceptor interactions for the adsorption/activation of amines and CO 2 , which promotes the synergistic oxidation-reduction process.
研究领域:
材料科学
·
环境科学
·
有机化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Yi Zhou,Wenfeng Zhao
Designing a low-cost and efficient photocatalytic system to produce high-valuable carbonates from the cycloaddition of CO 2 by using clean and renewable sunlight as the driving force shows great research potential. Here, a commercially available 4,4''-diamino-p-terphenyl (DT) was directly employed to promote the photocatalytic cycloaddition of CO 2 and various epoxides under visible light irradiation. As high as 95 % yield of target carbonate was obtained using blue LED (>450 nm) as a light source for 6 h under solvent-free/atmospheric CO 2 /room temperature conditions. Even under irradiation of natural light, a good yield of 68 % carbonate can also be achieved under ambient conditions. Moreover, in situ EPR and a series of controlled experiments were conducted to investigate the plausible photocatalytic mechanism, demonstrating that amino-containing DT with both π-π and p-π conjugated structure provides abundant basic sites and photogenerated electrons/holes as active sites for CO 2 activation and ring opening of epoxides at the same time.
研究领域:
化学
·
环境科学
·
材料科学
✓ 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）