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1.
Xueru Chen Yin Zhang Dashui Yuan Wu Huang Jing Ding Hui Wan Wei-Lin Dai Guofeng Guan 《材料科学技术学报》2021,71(12):211-220
Porous g-C3N4 nanosheets (PCN) were prepared by the nickel-assisted one-step thermal polymerization method.Hydrogen (H2) which was produced by the reaction between nickel (Ni) foam and ammonia (NH3) defined the structure and properties of PCN.During the formation of PCN,the participation of H2 not only enhanced the spacing between layers but also boosted the specific surface area that more active sites were exposed.Additionally,H2 promoted pores formation in the nanosheets,which was beneficial to the transfer of photons through lamellar structure and improved the absorption efficiency of visible light.Remarkably,the obtained PCN possessed better Cr(Ⅵ) photocatalytic reduction efficiency than pure g-C3N4.The reaction rate constant (k) of PCN (0.013 min-1) was approximately twice that of bare g-C3N4 (0.007 min-1).Furthermore,the effects of original pH and concentration of Cr(Ⅵ)-containing solution on removal efficiency of Cr(Ⅵ) were explored.A possible photocatalytic mechanism was proposed based on the experiments of radical scavengers and photoelectrochemical characterizations. 相似文献
2.
Gui-Yang Luo Yi-Jing Gu Yuan Liu Zi-Liang Chen Yong-lin Huo Fu-Zhong Wu Yi Mai Xin-Yi Dai Yong Deng 《Ceramics International》2021,47(8):11332-11339
LiFePO4 modified by N-doped graphene (NG) with a three-dimensional conductive network structure was synthesized via a one-step in situ hydrothermal method. The effects of N amount of NG on the phase structure, morphology, and electrochemical properties of LiFePO4 are investigated in this study. X-ray diffraction (XRD) results show that doping suitable N amounts in NG do not alter the crystal structure of LiFePO4, and scanning electron microscopy (SEM) images show that NG can slightly reduce the particle size of LiFePO4. The high-resolution transmission electron microscopy (HRTEM) results show that the LiFePO4 particles are well covered and connected by NG. The electrochemical performance confirms that LiFePO4 modified by 20% N-doped graphene (named LFP/NG-4) displays a perfect specific capacity of 166.6 mAh·g?1 at a rate of 0.2C and can reach 125 mAh·g?1 at a rate of 5 C. Electrochemical impedance spectroscopy (EIS) results illustrate that the charge transfer resistance value of the LFP/NG-4 composite is only 58.6 Ω, which is very low compared with LiFePO4. Cyclic voltammetry (CV) tests indicate that the addition of 20% N-doped graphene can effectively reduce electrode polarization and improve reversibility. The LFP/NG-4 composite with a three-dimensional conductive network structure can be regarded as a promising cathode material for Li-ion batteries. 相似文献
3.
Yuanyuan Chen Jian Peng Tian Sheng Ruixuan Qin Shuqi Dai Zaifa Shi Zichao Tang Laisen Wang Qinghua Zhang Bin Han Liping Sun Jun Xu Jian Weng 《Advanced functional materials》2021,31(42):2104246
Radicals are closely related to human life and health and have been widely used in biology, chemistry, functional materials, etc. However, the high reactivity, disorder, and short half-lives limit their wide applications. Therefore, it remains a great challenge to prepare stable and ordered radicals. Herein, radicals are prepared with protective umbrellas (diethylmethyleneamine, DEMA) that are integrated on the surface of 2D layered materials to isolate water and oxygen and enhance the stability of radicals. Taking 2D black phosphorus (BP) as an example: triethylamine reacts with dichloromethane to form quaternary ammonium salts with further Hoffmann elimination to produce DEMA radicals that could react with one electron of a lone pair electrons in P on the surface of BP to produce P radicals, which shows a prolonged half-life of 21 days at room temperature. First-principle calculations and electron paramagnetic resonance fitting confirm that the steric hindrance constructed by dense DEMA passivation layer acts as a protective umbrella and the 2D coupling of P radicals and other P atoms in 2D BP plane to enhance the stability and strong superexchange interaction of P radicals. Furthermore, it is a general strategy to produce stable radicals integrated on the 2D plane. 相似文献
4.
Nengbing Long Yanqing Fu Tianxiang Xu Dashuang Ding Shaoqian Zhang Shengzhi Sun Shiliang Kang Tiefeng Xu Shixun Dai Qiuhua Nie Changgui Lin 《Journal of the European Ceramic Society》2021,41(8):4584-4589
The confinement of CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (NCs) in a stabilized inorganic glass matrix is a new strategy for improving their long-term stability and promoting their applications in the optoelectronic field. Here, in situ nanocrystallization strategy is developed to precipitate CsPbBr3?xIx NCs with arbitrary I/Br ratio among an elaborately designed GeS2–Sb2S3-based chalcogenide glass matrix. Spherical CsPbBr3?xIx NCs are homogeneously distributed in the glass matrix after thermal treatment. The photoluminescence (PL) spectra show that the emission peaks of CsPbBr3?xIx NCs can be tuned from 570 nm to 722 nm with the replacement of Br by I. The fs transient absorption (TA) spectra reveal that there exists some structural defects in the NCs, leading to short PL decay life. This work would shed light on confining CsPbX3 NCs into glassy matrices, facilitating their future applications in photoelectronic fields. 相似文献
5.
Chemistry and Technology of Fuels and Oils - Through the analysis of the reservoir seepage capacity and high-pressure mercury intrusion porosimetry, the minimum flow pore throat radius and the... 相似文献
6.
Ruizhi Hu Chen Dai Chunmei Wang Jie Lin Hui Hu Zhifang Li Han Lin Li Ding Yu Chen Bo Zhang 《Advanced functional materials》2021,31(25):2101660
As an anticancer drugs, arsenic trioxide (ATO) has been certified to efficiently treat refractory acute promyelocytic leukemia (APL). Unfortunately it suffers from limited therapeutic potency for solid tumors due to its in vivo restricted administration dose and rapid renal clearance. Herein, distinct 2D arsenic-phosphorus (AsP) nanosheets are engineered by adopting an alloy strategy followed by exfoliation, which can confine toxic arsenic into AsP crystals, thus significantly improving the biosafety and biocompatibility of arsenic-based chemotherapeutic drugs. Of particular note, the high light absorption and strong photothermal-conversion efficiency (37.6%) in the second near infrared biowindow (NIR-II) of AsP nanosheets not only endow them with desirable contrast-enhanced photoacoustic imaging properties, but also achieve efficient local tumor hyperthermia, which further synergistically triggers the in-situ transformation from low toxic/nontoxic AsP crystals into highly toxic arsenic species, exerting a strong arsenic-mediated antineoplastic effect. Both in vitro and in vivo data verify the synergy between photonic therapy in NIR-II and enhanced chemotherapy as enabled by AsP nanosheets, paving the way for efficient nanomedicine-enabled arsenic-based chemotherapeutic tumor treatment. 相似文献
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9.
To investigate the evolution of the structural and enhanced magnetic properties of GdMnO3 systems induced by the substitution of Mn with Cr, polycrystalline GdMn1-xCrxO3 samples were synthesized via solid-state reactions. XRD characterization shows that all GdMn1-xCrxO3 compounds with single-phase structures crystallize well and that Cr3+ ions entering the lattice sites of GdMnO3 induce structural distortion. SEM results indicate that the grain size of the synthesized samples (a few microns) decreases as the Cr substitution concentration increases. Positron annihilation lifetime spectroscopy reveals that vacancy-type defects occur in GdMn1-xCrxO3 ceramics and that the vacancy size and concentration clearly change with the Cr content. The temperature and field dependence of the magnetization curves show that Cr substitution significantly influences the magnetic ordering of the gadolinium sublattice, improving the weak ferromagnetic transition temperature and magnetization of GdMn1-xCrxO3. The enhanced magnetization of GdMn1-xCrxO3 is closely related to the vacancy defect concentration. 相似文献
10.
膨胀剂、减缩剂对超高性能混凝土自收缩性能的影响 总被引:1,自引:0,他引:1
为了解决超高性能混凝土(ultra-high performance concrete,UHPC)存在的收缩开裂风险高等问题,研究膨胀剂、减缩剂对UHPC自收缩性能的影响,开展单掺膨胀剂或减缩剂UHPC的扩展度、基本力学性能及自收缩规律的试验研究,并在此基础上对膨胀剂与减缩剂双掺后的减缩效果进行研究.试验结果表明,膨胀剂或减缩剂单掺均提高UHPC扩展度;膨胀剂或减缩剂单掺均降低28 d抗压强度;掺膨胀剂、减缩剂UHPC的28 d自收缩发展可分为3个阶段:快速发展期、缓慢发展期、平稳期;单掺膨胀剂或减缩剂均有效抑制UHPC各阶段的自收缩,其中,膨胀剂HP-CSA质量分数为6.0%时减缩效果最佳,28 d减缩率达93.6%,减缩剂SBT?-SRA(I)质量分数为1.5%时减缩效果最佳,28 d减缩率为43.0%;膨胀剂与减缩剂双掺时未产生协同效应. 相似文献