JOURNAL OF CHROMATOGRAPHY A
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2016
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IF 3.926
Shuqin Liu,Qingkun Hu,Juan Zheng,Lijun Xie,Songbo Wei,Ruifen Jiang,Fang Zhu,Yuan Liu,Gangfeng Ouyang
A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m -xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10–1.13 ng L −1 for BTEX and 0.05–0.49 ng L −1 for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6–124.2% for BTEX and 77.2–113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2017
·
IF 3.582
Xiaoling Tan,Xueqiu Wang,Qingqing Liu,Jian Zhou,Peiping Zhang,Shudong Zheng,Shiding Miao
Magnetic cobalt ferrite (CoFe 2 O 4 ) particles were synthesized via a solvothermal pathway by using the gel of natural lotus roots as bio-gel template. Samples with porous structure and of large specific area (∼95.6 m 2 /g) were prepared, which were assembled by CoFe 2 O 4 particles of uniform sizes ( ca. 15.0 nm). The annealed CoFe 2 O 4 nanoparticles were proven to be highly efficient catalysts for aerobic oxidation of cyclohexane . Factors such as oxygen pressure, temperature, reaction time and self-catalysis by adding cyclohexanone have been studied in view of improving the conversion of cyclohexane as well as the selectivity of KA oil (cyclohexanone and cyclohexanol). Optimum parameters were found at an initial O 2 pressure of 1.6 MPa when the reaction was conducted for 6.0 h at the temperature of 150 °C. The maximum conversion of cyclohexane oxidation reaches 16.43%, and the selectivity 90.3% for KA oil was obtained. This research provides a facile way of developing green catalysts in the aerobic oxidation of cyclohexane.
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Journal of Materials Chemistry A
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2017
·Vol. 5
·期 16
·7423-7432
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IF 8.867
Lin Fan,Yi Ding,Jingshan Luo,Biao Shi,Xin Yao,Changchun Wei,Dekun Zhang,Guangcai Wang,Yun Sheng,Yifeng Chen,Anders Hagfeldt,Ying Zhao,Xiaodan Zhang
It has been proposed that introducing the chlorine anion into a CH3NH3PbI3 perovskite material can substantially improve the materials properties as well as the solar cell performance. To elucidate the role of chlorine in perovskite solar cells (PSCs), here we introduced PbCl2 into the precursor, and studied the chlorine configuration evolution during perovskite film formation and the associated influence on PSC performance in detail. We found that chlorine could be successfully incorporated into the precursor film in the form of PbICl or PbCl2 through a properly designed preparation, and it was conserved in the final perovskite film with a configuration of MAPbCl3, PbICl or PbCl2 depending on the fabrication process. However, no evidence of a MAPbI3−xClx phase was observed, and it is considered that MAPbI3−xClx might be metastable or possesses a higher formation energy. In addition, we demonstrate that the formation of a porous PbICl scaffold in the precursor film plays a key role in high quality perovskite film realization, benefiting from an effective stress release during structure expansion after methylammonium iodide dripping. Moreover, we propose that residual amorphous PbCl2 can effectively passivate defects in perovskite film, and dramatically improve the film’s electrical properties. Finally, n–i–p type planar PSCs with efficiencies up to 19.45% were achieved. It should be mentioned that the whole process for the formation of the PSCs is performed at less than 100 °C, which is beneficial for a wide range of applications, such as flexible and tandem solar cells.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
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IF 2.76
Zaihang Zheng,Yan Liu,Yuan Bai,Jijia Zhang,Zhiwu Han,Luquan Ren
Inspired by typical creature living surface with hydrophobicity, the hydrophobic graphene surface was successfully achieved on aluminium alloy substrate by a novel route. It is composed of two steps: biomimetic microstructure processing (BMP) on substrate and then preparation-transfer process of graphene via chemical vapor decomposition (CVD). The surface structure morphology, wettability and anti-corrosion were systematically investigated. It was found that the static water contact angle for the as-prepared surface was as high as 130.8 ± 1°, demonstrating that the hydrophobic surface is formed on aluminium alloy substrate. It can be interpreted by the synergistic effect between BMP and CVD methods in constructing the biomimetic and hydrophobic graphene surface. Besides, the anti-corrosion property of Al alloy was improved by forming CVD-grown graphene coating on the substrates according to the results of electrochemical corrosion experiments. The synergistic method was not only applied to fabricate hydrophobic graphene film but also provided a versatile route in multifunctional graphene film suited in wide application.
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Energy Technology
·
2017
·Vol. 6
·期 4
·752-758
·
IF 2.789
Weihan Wang,Xichuan Yang,Jiajia Li,Haoxin Wang,Jincheng An,Li Zhang,Xiao Jiang,Ze Yu,Licheng Sun
As a champion hole-transporting material (HTM), 2,2′7,7′-tetrakis-( N , N -di- p -methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) has been widely used in solid-state dye-sensitized solar cells (ssDSCs). Owing to the low conductivity of Spiro-OMeTAD, a chemical doping strategy is commonly used to enhance its hole-transporting properties. In this study, we report a strong electron acceptor, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an additive for Spiro-OMeTAD along with its application in ssDSCs. We show that the conductivity of Spiro-OMeTAD increases from 5.31×10 −5 to 2.22×10 −4 S cm upon the addition of 0.04 % DDQ, and the power conversion efficiency (PCE) of the ssDSCs also increases. By utilizing a donor–π–acceptor sensitizer with a high coefficient and an HTM with an optimized doping ratio, we were able to achieve a high PCE of 6.37 % for the ssDSCs under 100 mW cm −2 AM1.5G simulated illumination, in comparison to the PCE of the pristine device, which was only 3.50 %. An increase in the application of benzoquinone-based materials for organic electronics is expected, especially for solar-cell applications.
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Nanoscale
·
2016
·Vol. 8
·期 12
·6600-6608
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IF 7.76
Shimao Wang,Weiwei Dong,Xiaodong Fang,Qingli Zhang,Shu Zhou,Zanhong Deng,Ruhua Tao,Jingzhen Shao,Rui Xia,Chao Song,Linhua Hu,Jun Zhu
The role of remnant PbI2 in CH3NH3PbI3 films is still controversial, some investigations have revealed that the remnant PbI2 plays a passivation role, reduces the charge recombination in perovskite solar cells (PSCs), and improves the performance of PSCs, but the opposing views state that remnant PbI2 has no passivation effect and it would deteriorate the stability of the devices. In our investigation, the CH3NH3PbI3 films have been prepared by a two-step spin-coating method and the content of the remnant PbI2 in CH3NH3PbI3 films has been tuned by varying the preparation temperature. It has been found that increasing the heating temperature could increase the coverage of spin-coated PbI2 films, which has led to high coverage CH3NH3PbI3 films and more remnant PbI2 in CH3NH3PbI3 films, and as a result, the performance of PSCs was enhanced obviously and the maximum power conversion efficiency of 14.32 ± 0.28% was achieved by the PSCs prepared at 130/120 °C (PbI2 films were heated at 130 °C and CH3NH3PbI3 films were heated at 120 °C). Furthermore, the dark current, electrochemical impedance spectroscopy and time-resolved fluorescence emission decay measurements revealed that the charge recombination in PSCs has been gradually suppressed and the fluorescence emission lifetime has gradually increased with the content of remnant PbI2 increasing. Thus, the passivation effects of the unreacted and decomposed PbI2 in improving the performance of PSCs have been confirmed unquestionably.
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RSC Advances
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2016
·Vol. 6
·期 19
·15577-15584
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IF 3.289
Haixia Xuan,Xi Chen,Yinghui Wu,Kena Song,Yuenan Li,Ruchuan Liu
The impact of the nanostructures of conjugated polymers on their electronic properties is significant. We notice that poly(3-hexylthiophene-2,5-diyl) (P3HT) can form nano-islands and nano-fibrils, and both of them show an similar single-layer thickness (∼1.5–1.6 nm) as evaluated by atomic force microscopy (AFM). The Raman spectra indicate the highest degree of chain planarity and crystallinity in the nano-islands. By using scanning Kelvin probe microscopy (SKPM) and electrostatic force microscopy (EFM), we image the surface potential at the nanometer scale and quantitatively estimate the charges on these nanostructures as modulated by light. Both results are consistent with each other: the surface potential increases on switching on the light, and the photo-induced charges are around 15–25% and positive. A similar amount of the photo-induced charges in both P3HT islands and fibril is consistent with the π–π stacking nature of these nanostructures. As P3HT is a hole-conducting molecule, positive charges are found easily injected into a single island by a positively biased EFM tip, and then the injected charges are able to propagate all over the island.
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Energy Technology
·
2017
·Vol. 5
·期 10
·1836-1843
·
IF 2.789
Haoxin Wang,Ze Yu,Xiao Jiang,Jiajia Li,Bin Cai,Xichuan Yang,Licheng Sun
The inorganic p-type semiconductor CuI possesses several unique characteristics such as high transparency, low-production cost, high hole mobility, and good chemical stability and is a promising hole-transporting material candidate that can be explored in solar-cell devices. Herein, we adopt a simple solid–gas reaction method to fabricate a uniform CuI film by exposing a thermally evaporated copper film to iodine vapor and apply it as a hole-transporting layer (HTL) in inverted planar perovskite solar cells (PSCs). The optimized devices display a promising power conversion (PCE) efficiency of 14.7 %, with an open-circuit voltage of 1.04 V, a short-circuit current density of 20.9 mW cm −2 , and a fill factor of 0.68. This is one of the highest PCE values reported so far for CuI-based HTL in PSCs. Moreover, the devices studied also exhibit good long-term stability at ambient atmosphere, arising from the hydrophobicity of CuI HTL. The results highlight that CuI fabricated using the simple and low-temperature processing method presented here holds great promise as low-cost alternative HTL material for the development of efficient and stable inverted planar PSCs in the future.
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ACS Applied Materials & Interfaces
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2017
·
IF 7.504
Han Li,Chao Liang,Yingliang Liu,Yiqiang Zhang,Jincheng Tong,Weiwei Zuo,Shengang Xu,Guosheng Shao,Shaokui Cao
Grain boundaries act as rapid pathways for nonradiative carrier recombination, anion migration, and water corrosion, leading to low efficiency and poor stability of organometal halide perovskite solar cells (PSCs). In this work, the strategy suppressing the crystal grain boundaries is applied to improve the photovoltaic performance, especially moisture-resistant stability, with polyvinylammonium carbochain backbone covalently connecting the perovskite crystal grains. This cationic polyelectrolyte additive serves as nucleation sites and template for crystal growth of MAPbI3 and afterward the immobilized adjacent crystal grains grow into the continuous compact, pinhole-free perovskite layer. As a result, the unsealed PSC devices, which are fabricated under low-temperature fabrication protocol with a proper content of polymer additive PVAm·HI, currently exhibit the maximum efficiency of 16.3%. Remarkably, these unsealed devices follow an “outside-in” corrosion mechanism and respectively retain 92% and 80% of the initial PCE value after being exposed under ambient environment for 50 days and 100 days, indicating the superiority of carbochain polymer additives in solving the long-term stability problem of PSCs.
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MICROCHIMICA ACTA
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2017
·Vol. 184
·期 4
·1169-1176
·
IF 4.58
Kong Deying,Bao Tao,Chen Zilin
The covalent organic framework LZU1 (Lan Zhou University-1) is one of the imine-based covalent organic frameworks (COFs) that possesses attractive properties such as structural regularity, stability and good porosity. This work reports on the in-situ synthesis of COF-LZU1 on the inner walls of capillary column for open-tubular capillary electrochromatography (OT-CEC). The fused-silica capillary was first modified with 3-aminopropyltriethoxysilane and glutaraldehyde. Epitaxial growth of COF-LZU1 on the inner walls was accomplished by Schiff base reaction. The formation of COF-LZU1 was confirmed by SEM and FT-IR. The COF-LZU1 coating increases the interactions between analytes and coating, which remarkably improves the CEC separation selectivity of neutral analytes, amino acids and nonsteroidal anti-inflammatory drugs. The COF-LZU1-modified column exhibits good stability and repeatability. The precisions (relative standard deviations) for intra-day, inter-day and column-to column are <1.6%, 5.6% and 6.8%, respectively. Hence, the imine-based COFs represent attractive stationary phase for application in CEC separations.
Covalent organic framework (COF-LZU1) was in situ synthesized on the inner wall of a capillary column for electrochromatographic separation of nonsteroidal drugs and amino acids.
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GREEN CHEMISTRY
·
2016
·Vol. 18
·期 11
·3370-3377
·
IF 8.506
Wenjing Yang,Haiyang Cheng,Bin Zhang,Yan Li,Tong Liu,Mingli Lan,Yancun Yu,Chao Zhang,Weiwei Lin,Shin-ichiro Fujita,Masahiko Arai,Fengyu Zhao
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) was studied with a homogeneous RuCl2(PPh3)3 catalyst in supercritical CO2 (scCO2). The conversion of LA was observed to increase with CO2 pressure and the possible reasons for this rate acceleration were discussed, including the molecular interactions of CO2 with the reacting and catalytic species as well as the acidity and phase behavior of the reaction mixture. The interaction between CO2 and RuCl2(PPh3)3 was significant, which resulted in the production of an active RuHCl(CO)(PPh3)3 complex and thus enhanced the rate of hydrogenation in the presence of CO2.
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Energy Technology
·
2016
·Vol. 5
·期 8
·1257-1264
·
IF 2.557
Hongwei Zhu,Fei Zhang,Xicheng Liu,Mengna Sun,Jianlei Han,Jing You,Shirong Wang,Yin Xiao,Xianggao Li
A hole-transport material (HTM), 1,1,2,2-tetrakis[4-(3,6-di- tert -butyl-9 H -carbazol-9-yl)phenyl]ethene (TTBCPE), was prepared straightforwardly and employed in the fabrication of perovskite solar cells (PSCs). The investigated HTM with tetraphenylethene as the core and tert -butylcarbazole as terminal units was synthesized in two steps from commercially available and cheap raw materials. The devices based on TTBCPE without the use of any dopants and additives exhibited a power conversion efficiency (PCE) of 12.65 %, which is comparable to 14.46 % obtained by using devices based on 2,2′,7,7′-tetrakis( N , N ′ - di- p -methoxyphenylamino)-9,9′-spirobifluorene ( p -doped spiro-OMeTAD). Importantly, the device based on TTBCPE showed a higher stability than devices based on doped spiro-OMeTAD if stored under ambient conditions. In this regard, this easily synthesized and dopant-free system paves a new way to develop low-cost HTMs.
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