摘要：
In the present work, the photodegradation of Rhodamine B with different pH values by using Bi(2)O(3) microrods under visible-light irradiation was studied in terms of the dye degradation efficiency, active species, degradation mechanism, and degradation pathway. X-ray diffractometry, polarized optical microscopy, scanning electron microscopy, fluorescence spectrophotometry, diffuse reflectance spectra, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, UV-visible spectrophotometry, total organic carbon, and liquid chromatography-mass spectroscopy analysis techniques were used to analyze the crystal structure, morphology, surface structures, band gap values, catalytic performance, and mechanistic pathway. The photoluminescence spectra and diffuse reflectance spectrum (the band gap values of the Bi(2)O(3) microrods are 2.79 eV) reveals that the absorption spectrum extended to the visible region, which resulted in a high separation and low recombination rate of electron-hole pairs. The photodegradation results of Bi(2)O(3) clearly indicated that Rhodamine B dye had removal efficiencies of about 97.2%, 90.6%, and 50.2% within 120 min at the pH values of 3.0, 5.0, and 7.0, respectively. In addition, the mineralization of RhB was evaluated by measuring the effect of Bi(2)O(3) on chemical oxygen demand and total organic carbon at the pH value of 3.0. At the same time, quenching experiments were carried out to understand the core reaction species involved in the photodegradation of Rhodamine B solution at different pH values. The results of X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffractometer analysis of pre- and post-Bi(2)O(3) degradation showed that BiOCl was formed on the surface of Bi(2)O(3), and a BiOCl/Bi(2)O(3) heterojunction was formed after acid photocatalytic degradation. Furthermore, the catalytic degradation of active substances and the possible mechanism of the photocatalytic degradation of Rhodamine B over Bi(2)O(3) at different pH values were analyzed based on the results of X-ray diffractometry, radical capture, Fourier-transform infrared spectroscopy, total organic carbon analysis, and X-ray photoelectron spectroscopy. The degradation intermediates of Rhodamine B with the Bi(2)O(3) photocatalyst in visible light were also identified with the assistance of liquid chromatography-mass spectroscopy.
作者机构：
[Ma, Dechong; Pan, Sai; Ma, DC; He, Guowen; Tan, Mingjun] Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.;[Zhao, Jingzhe] Hunan Univ, Coll Chem & Chem Engn, Changsha 410082, Peoples R China.
通讯机构：
[Ma, DC; He, GW ] H;Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
关键词：
Bi nanostructures;pH values;Photocatalytic activity;Morphology controlled synthesis
摘要：
The catalytic activity of photocatalyst is strongly dependent on the phase structures, grain size and particle morphology of the catalyst. In this paper, the controlled synthesis of bismuth(Bi) with different morphologies (nanoparticles, nanorods, nanocubes and micro-spheres) has been successfully realized by adjusting different experimental parameters. The Bi nanostructures were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), UV-vis absorption spectroscopy (UV-Vis). The PL spectra shown that the reduction of the size of Bi nanomaterials can decrease the recombination rate of photoelectrons and holes, which leads to the effective separation of photocharge carriers and the better photocatalytic performance of Bi nanomaterials. The energy gaps of Bi nanoparticles, nanorods, nanocubes and microspheres are 2.57 eV, 2.69 eV, 2.99 eV and 3.16 eV respectively. The degradation activity of Bi nanostructures with different sizes on organic dyes showed that 99.9%, 98.9%, 97% and 68.3% degradation of RhB was observed after 90-min visible light irradiation for Bi nanoparticles (20-50 nm), nanorods (20 nm in diameter and 1 mu m in length) nanocubes (150-200 nm) and micro-spheres (10 mu m), respectively. The results indicated that if the grain sizes of the Bi samples are reduced from micro-size to nano-size, their catalytic activities dramatically increase. At the same time, the achieved results also reveal that Bi2O3 and BiOCl were found in Bi surfaces before and after catalytic degradation, which was confirmed by XPS and FTIR technology. In addition, the catalytic activity of Bi with the same morphology increased with the decrease of pH value. Furthermore, the Bi samples still retained excellent catalytic activity after 40 cycles, the removal rate could also reach 73.5% for the 40th cycling.
期刊：
Materials Chemistry and Physics,2023年310 ISSN：0254-0584
通讯作者：
Ma, Dechong;He, GW
作者机构：
[Ma, Dechong; Pan, Sai; Ma, DC; He, Guowen; Tan, Mingjun] Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.;[Zhao, Jingzhe] Hunan Univ, Coll Chem & Chem Engn, Changsha 410082, Peoples R China.
通讯机构：
[Ma, DC; He, GW ] H;Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
关键词：
Bi nanostructures;Controlling agent;Catalysis degradation;Morphology-controlled synthesis
摘要：
Bi with four different morphologies (zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanowires, twodimensional (2D) nanoplates, and three-dimensional (3D) shuttle like structures) was successfully synthesized by changing the synthetic conditions. The Bi nanostructures were characterized in terms of structure, morphology, surface characteristics, optical properties and catalytic activity using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), UV-vis absorption spectroscopy (UV-Vis) and total organic carbon (TOC) analyzer techniques, respectively. The PL spectra is shown that the reduction of the size of Bi nanomaterials can reduce the recombination rate of photoelectrons and holes, which leads to the effective separation of photocharge carriers and the lowest photoelectron and hole recombination rates. The band gap values of Bi nanoparticles, nanowires, nanoplates and shuttle like structures are 2.71 eV, 2.76 eV, 2.92 eV and 3.22 eV respectively, favouring the harvesting of visible-light. The experimental results of the degradation performance of Bi with different morphologies exhibited that 99.9%, 97.9%, 96.2% and 74.4% degradations of the Rhodamine B (Rh B) was observed for Bi nanoparticles, nanowires, nanoplates and shuttle like structures, respectively. During the degradation of RhB, with the prolongation of treatment time to 90 min, the highest removal rates of chemical oxygen demand (COD) and TOC was 73.5% and 68.4%, respectively. According to TOC analysis, more than 68% of the carbon in the dyes will produce CO2 products. The removal efficiency is attributed to the production of center dot O2-, center dot OH and h+ and their mineralization to RhB. At the same time, the achieved results also reveal that Bi2O3 and BiOCl was found in Bi surfaces before and after catalytic degradation, which was confirmed by XPS and FTIR technology. In addition, Bi with the same morphology performed different catalytic activities in Rh B solution with different pH values. It was found that the degradation efficiency increased evidently when the pH value decreased. The mechanism of Bi photocatalytic activity was proposed based on the results of product analysis, radical capture and XPS analysis.
摘要：
Abstract: In this thesis, polypropylene film was used as adhesive to prepare wood-plastic boards by stacking with the log board. By changing the surface of the wood panel, the amount of polypropylene film and the direction of the wood grain, a multilayer wood-plastic composite panel was successfully prepared by the hot pressing molding process, the impact properties, hardness, water absorption, aging test and other related tests were carried out to study the mechanical properties of materials under different variables. The results show that the impact strength of the composite sheet prepared by double polypropylene film and staggered arrangement is the best, reaching 34.23 kJ/m2, and the water absorption rate is the minimum of 41.8%. The increase in the amount of polypropylene film can make the board bond more firmly, reduce the surface pores of the board, improve the impact strength, reduce the water absorption and improve the aging resistance.#@#@#摘要: 本论文使用聚丙烯膜作为胶黏剂与原木板叠加而制备成木塑复合材料。通过对木板表面的改变、聚丙烯薄膜的用量和木纹方向的变化，采用热压成型工艺成功制备了多层的木塑复合板材，并对其进行冲击性能、硬度、吸水率、老化试验等相关测试，研究了不同变量下材料的力学性能。结果表明，使用双层聚丙烯膜且交错排列制备的复合板材冲击强度最好，达到34.23 kJ/m2，吸水率最小是41.8%。聚丙烯膜用量的增加可以使其板材结合更加牢固，减少木板表面孔隙，提高了冲击强度，降低了吸水率，提高了抗老化性能。
摘要：
Abstract: In this paper, the content of free formaldehyde in large core board was successfully determined by perforated extraction and acetyl acetone spectrophotometry. In the environment of constant temperature shaking water bath and acetic acid-ammonium acetate buffer solution (pH = 6), formaldehyde reacts with acetyl acetone to produce a stable yellow compound 3-methylene-2, 4-pentanedione, which is then measured at a wavelength of 412 nm Its absorbance. The results show that when using perforated extraction and acetyl acetone spectrophotometry to determine the formaldehyde content in large core plates, the formaldehyde content has a good linear relationship with the absorbance in the range of 0~10 μg/ml, and its linear correlation coefficient (R)reaches 0.99872. The recovery rate of standard addition was 97.6%~99.7%, the average recovery rate of standard addition was 99.0%, and the detection limit was 0.0890 μg/ml. It can be seen that the method has high sensitivity and high accuracy, and can be applied to the determination of formaldehyde content in large core boards.#@#@#摘要: 本论文采用穿孔萃取法和乙酰丙酮分光光度法成功测定了大芯板中游离的甲醛的含量。甲醛与乙酰丙酮反应，产生稳定的黄色化合物3-亚甲基-2,4-戊二酮，再于波长412 nm处测定其吸光度。试验测得的板材中甲醛含量为0.0159 mg/m3。结果表明，利用穿孔萃取法和乙酰丙酮分光光度法测定大芯板中的甲醛含量时，甲醛含量在0~10 μg/ml范围内与吸光度呈现出良好的线性关系，其线性相关系数为r = 0.99872，加标回收率为97.6%~99.7%，平均加标回收率为99.0%，检出限为0.0890 μg/ml。由此可见，该法灵敏度较高，准确度较高，可适用于大芯板中甲醛含量的测定。
期刊：
Journal of Alloys and Compounds,2022年922:166176 ISSN：0925-8388
通讯作者：
Chang Miao
作者机构：
[Miao, Chang; Mou, Haoyi; Nie, Shuqing; Xiao, Wei; Xin, Yu; Wen, Minyue] Yangtze Univ, Coll Chem & Environm Engn, Jingzhou 434023, Peoples R China.;[Miao, Chang; Xin, Yu; Wen, Minyue; He, Guowen] Hunan City Univ, All Solid State Energy Storage Mat & Devices Key L, Yi Yang 413000, Peoples R China.
通讯机构：
[Chang Miao] C;College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434023, PR China<&wdkj&>All-Solid-State Energy Storage Materials and Devices Key Laboratory of Hunan Province, Hunan City University, Yi Yang, 413000, PR China
摘要：
The SnCu-SiO2 @CNFs composite nanofibers are successfully fabricated by electrospinning and subsequent heat treatments, in which the Sn-Cu alloy particles are uniformly confined in carbon nanofibers (CNFs) in the presence of SiO2. The characterization results show that incorporating SiO2 into the CNFs matrix can mitigate the problem of the phase separation between Sn-Cu alloy particles and CNFs and increase the fibrous structural integrity of the composite electrodes. Importantly, the SnCu-SiO2 @CNFs-1.0 composite electrode displays the improved electrochemical performance when the amount of Cu(Ac)(2) is controlled at 1.0 mmol, in which the discharge specific capacity of the electrode not only delivers 501.8 mAh/g after 100 cycles at 100 mA/g, but also retains 467.4 mAh/g after rate cycles when the current density is abruptly recovered to 100 mA/g. Moreover, the SnCu-SiO2 @CNFs-1.0 electrode can possess an enhanced Li+ diffusion coefficient of approximately 1.58 x 10(-16) cm(2) s(-1) and a high Warburg coefficient of 568.9 omega cm(2) s(-0.5) at room temperature. The enhanced electrochemical performance can be partly ascribed to the complete encapsulation of Sn-Cu alloy particles by the CNFs matrix, and partly to the promotion of the over-all electronic conductivity. Furthermore, the flexible and conductive CNFs matrix and the stable Cu6Sn5 phase can conjoinedly accommodate the volume change of the electrodes during charge/discharge processes. Therefore, the facile strategy for encapsulating Sn-Cu alloy particles into CNFs may offer some a prospective instruction for the alloy anodes in the field of energy storage. (C) 2022 Elsevier B.V. All rights reserved.
