Communications Chemistry
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2018
·Vol. 1
·期 1
·1-11
·
IF 0
Li Hu,Zhao Wenfeng,Saravanamurugan Shunmugavel,Dai Wenshuai,He Jian,Meier Sebastian,Yang Song,Riisager Anders
The production of liquid fuels and fine chemicals often involves multi-step reaction processes with selective hydrogenation as one of the key steps. This step most often depends on high-pressure excess hydrogen gas, fossil resources, and newly prepared metallic catalysts. Here we describe an approach to tune activity and selectivity toward transfer hydrogenation of renewable biomass derivatives over commercially available Pd/C using liquid hydrosilane as hydrogen source. The appropriate control of water-doping content, acid type, reaction temperature, and liquid H − donor dosage permits the selective formation of four different value-added products in high yields (≥90%) from bio-based furfural under mild reaction conditions (15–100 °C). Mechanistic insights into the hydrosilane-mediated cascade reactions of furfural are obtained using isotope labeling. The catalyst is recyclable and can selectively reduce an extensive range of aromatic carbonyl compounds to the corresponding alcohols or hydrocarbons in 83–99% yield, typically at 25–40 °C.
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NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 14
·11715-11723
·
IF 3.201
Abdelaal S. A. Ahmed,Wanchun Xiang,Anna Gu,Xiaowei Hu,Ibrahim Amiinu Saana,Xiujian Zhao
A carbon black–silicon nitride (CB–Si3N4) nanocomposite is prepared as a cost-effective counter electrode (CE) for dye-sensitized solar cells (DSSCs). The CB–Si3N4 nanocomposite is coated on an FTO substrate via the screen printing method. The results demonstrate that when the thickness is fixed at 4.7 μm the CB–Si3N4 composite CE exhibits lower charge transfer resistance and higher electrocatalytic activity towards the reduction of tri-iodide over the CB and Si3N4 electrodes. The CB–Si3N4-3% CE achieves the best catalytic activity and the prepared DSSC shows a power conversion efficiency of 8.06%. As the thickness of the CB–Si3N4-3% CE increases, the electrocatalytic ability is enhanced, and the charge transfer resistance at the electrolyte/CE interface decreases. The overall performance of the CB–Si3N4-3% CE with a thickness of 14.1 μm is comparable to that of Pt-doped CEs. Furthermore, a DSSC equipped with CB–Si3N4-3% CEs of 14.1 μm thickness exhibits a high efficiency of 8.37%, which is comparable to that of the Pt-based DSSC (8.50%). The simple preparation technique, outstanding electrocatalytic activity, and low cost of production allow the CB–Si3N4 nanocomposite to be a promising and efficient CE for DSSCs.
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高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 6
·3459-3469
·
IF 3.809
Zhou Mengyao,Zhang Huihui,Qiao Yan,Li Chang Ming,Lu Zhisong
Abstract Textile-based flexible supercapacitors have attracted tremendous attention due to their great potentials in wearable electronics. It is highly desirable to develop facile methods, which are compatible with conventional textile industry, for the fabrication of high-performance and ultra-flexible textile-supported supercapacitors. Herein, a sandwich-structured supercapacitor with a poly(vinyl alcohol)/H 3 PO 4 -soaked cotton fabric as the electrolyte matrix, separator and supporting layer was prepared via screen-printing and transfer-printing techniques. Digital photographs and scanning electron micrographs were collected to verify the construction of the cotton fabric-sandwiched supercapacitor. The device possesses a gravimetric capacitance of 63.7 F g −1 at a current density of 1 A g −1 . After 2000 charging/discharging cycles, a capacitance retention of 85% could be achieved. The as-prepared supercapacitor can tolerate 100 times of bending or twisting with the capacitance maintaining at 89.7 and 93.3% of the original level, respectively. By designing the screen-printing mask, a squirrel-patterned supercapacitor was manufactured, showing that the proposed approach could combine both functionality and aesthetics. To demonstrate its feasibility, three in-series connected supercapacitors were produced on a T-shirt to light up a red lamp. This work may provide a facile approach to fabricating ultraflexible textile-based supercapacitors for potential applications in smart textiles and wearable electronics. Graphical Abstract
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 8
·6151-6163
·
IF 3.442
Yan Dejian,Liu Jikai,Fu Xingchen,Liu Pingle,Luo He’an
Boron-rich semiconductors make significant contributions to the family of explored metal-free photocatalysts, which have attracted much attention in recent years. Boron carbide (B 4 C) belongs to a typical metal-free boron-rich photocatalyst which is facing difficulties in further optimization mainly due to the extreme conditions required for the synthesis of this material. In the present work, five different transition-metal catalysts (Fe, Co, Ni, Cu, and Zn) were investigated for lowering the crystallization temperature of B 4 C. Ni is the best catalyst for the reaction, and the crystalline mesoporous B 4 C powders can be obtained at merely 850 °C with a surface area of 130.55 m 2 g −1 , which is 27 times larger than commercial B 4 C. The photocatalytic properties of B 4 C prepared with Ni catalyst at different calcination temperatures were further evaluated by photocatalytic CO 2 reduction and generation of hydroxyl radicals. Both the crystallinity and surface area of the B 4 C would influence the final photocatalytic properties. For B 4 C photocatalysts, we firstly found that the crystallinity would influence the photogenerated holes more significantly while the surface area would have more significant influence on the photogenerated electrons. The B 4 C obtained at 950 °C exhibits the best photocatalytic activities for both CO 2 reduction and generation of ·OH radicals, which are 3.1 and 2.1 times higher than the commercial B 4 C, respectively. This present study may provide crucial references for the low-temperature synthesis of crystalline B 4 C and new opportunities for the application of the metal-free B 4 C photocatalysts to solar energy conversion.
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高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Qiuhong Bai,Qiancheng Xiong,Cong Li,Yehua Shen,Hiroshi Uyama
Hierarchical porous activated carbon (AC) materials were prepared from a composite of highly accessible carbon sources, sodium alginate and bacterial cellulose, by carbonization and KOH activation. The as-obtained carbon materials not only possessed rich oxygenated functionalities but also formed a hierarchical porous structure. The unique structures and chemical compositions of the resulting materials demonstrate good potential for use in supercapacitor electrode materials. The AC had a three-dimensional interconnected network structure consisting of sheet-like connected particles. Interestingly, the carbon material possessed high graphitization degree and good electrical conductivity. The electrochemical properties of electrodes were evaluated in a three-electrode system in 6 M KOH. Due to the synergistic effects of the rich oxygen content and the porous structure, the sample calcined at 700 °C showed a high gravimetric capacitance of 302 F/g, an excellent capacitance retention ratio of 75.2% at 10 A g −1 , and good cycling stability with 93.8% capacitance retention after 10,000 cycles. The as-obtained single electrode exhibited a very high energy density of 23.7 W h kg −1 , making it more interesting than commercial AC for practical applications. This study demonstrates that the utilization of abundant polymers from nature is a good route for fabricating high-performance supercapacitor electrode materials.
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高影响因子
POLYHEDRON
·
2018
·
IF 2.067
Ya-Nan Ren,Wei Xu,Zhen-Xiu Si,Lin-Xia Zhou,Yue-Qing Zheng
Two new uranyl compounds [NH 4 ][(UO 2 )(ipa) 1.5 ]·H 2 O 1 and [(UO 2 ) 2 ( μ 2 OH)( μ 3 OH)(ipa)(H 2 O)]·H 2 O 2 (H 2 ipa = isophthalic acid) have been synthesized under hydrothermal conditions and characterized by infrared spectra (IR), thermogravimetric analysis (TGA), elemental analyses and X-ray diffraction (XRD). Structural analysis reveals compound 1 exhibits two-dimensional (2D) framework through the bridging of ipa 2− anions, which was further construct to three-dimensional (3D) structure via π–π stacking interaction. Compound 2 presents a tetranuclear building block [(UO 2 ) 4 ( μ 2 OH) 2 ( μ 3 OH) 2 (H 2 O) 2 ] unit which was linked via μ 3 η 4 coordination mode ipa 2− anions to form one-dimensional (1D) chains structure. The fluorescence properties of the two compounds were investigated. The photocatalytic performance of compound 2 was also investigated and the results show that compound 2 exhibits good photocatalytic activity toward the degradation of tetracycline antibiotics under LEDs irradiation.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2018
·
IF 3.525
Haojie Wang,Chun Chen,Haimin Zhang,Guozhong Wang,Huijun Zhao
Bimetallic nanostructures have attracted great interest as efficient catalyst to enhance activity, selectivity and stability in catalytical conversion. Herein, we report a facile one-pot carbothermal route to in-situ controllable synthesize heterogeneous bimetallic Ni 3 Fe NPs@C nanocatalyst. The X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and N 2 adsorption-description results reveal that the Ni 3 Fe alloy nanoparticles are evenly embedded in carbon matrix. The as-prepared Ni 3 Fe NPs@C catalyst shows excellent selective hydrogenation catalytic performance toward the conversion of levulinic acid (LA) to γ-valerolactone (GVL) via both direct hydrogenation (DH) and transfer hydrogenation (TH). In DH of LA, the bimetallic catalyst achieved a 93.8% LA conversion efficiency with a 95.5% GVL selectivity and 38.2 mmol g −1 h −1 GVL productivity (under 130 °C, 2MPa H 2 within 2 h), which are 6 and 40 times in comparison with monometallic Ni NPs@C and Fe NPs@C catalysts, respectively. In addition, the identical catalyst displayed a full conversion of LA with almost 100% GVL selectivity and 167.1 mmol g −1 h −1 GVL productivity at 180 °C within 0.5 h in TH of LA. Under optimal reaction conditions, the DH and TH catalytic performance of 500-Ni 3 Fe NPs@C(3:1) catalyst for converting LA to GVL is comparable to the state-of-the-art noble-based catalysts. The demonstrated capability of bimetallic catalyst design approach to introduce dual-catalytic functionality for DH and TH reactions could be adoptable for other catalysis processes.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Hua Tian,Wentao Bao,Yang Jiang,Lin Wang,Lin Zhang,Ou Sha,Cunqi Wu,Faming Gao
The ingenious synthesis strategies have been highly desired to construct hybrid composites with intriguing properties for supercapacitors . Herein, Ni-Al LDH (layered double hydroxide)/NNDG (nitramine-N-doped graphene) hybrid composites with a layered structure were fabricated via a novel self-assembly process. Nitramine-N dopants anchored to graphene framework allow the self-immobilization of delaminated Ni-Al LDH nanolayers onto the surface of two-dimensional carbonaceous scaffolds and boost the abundance of Ni 3+ within hybrid composites along with the removal of interlayer anions within Ni-Al LDH-NO 3 . Remarkably, the combination of Ni-Al LDH with NNDG can not only enhance the utilization of electrochemically active matrixes in dependence on the increase of electrolyte accessible active sites, but also maximize the electrochemically active contact between inorganic macromolecules and carbonaceous matrixes in favor of the establishment of conductive architectures. Furthermore, Ni-Al LDH/NNDG hybrid composites achieve a specific capacity of 975 C g −1 at a specific current of 1.0 A g −1 with a capacity retention of 75% as the increase of specific currents to 10 A g −1 , superior to Ni-Al LDH-NO 3 and Ni-Al LDH/rGO hybrid composites. The hybrid supercapacitor comprised of Ni-Al LDH/NNDG hybrid composites as a positive electrode and activated carbon as a negative electrode attains a high energy density of 59 Wh kg −1 with a power density of 1991 W kg −1 at a specific current of 2.5 A g −1 and retains 95% of the initial capacitance after 10 000 cycles at a specific current of 10 A g −1 . The excellence electrochemical performance demonstrates clearly the potential application of self-assembled Ni-Al LDH/NNDG hybrid composites for hybrid supercapacitors.
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高影响因子
Sustainable Energy & Fuels
·
2018
·Vol. 2
·期 10
·2197-2205
·
IF 0
Daoqing Liu,Qianwei Li,Jinbao Hou,Huazhang Zhao
The low electronic conductivity of sulfur and the high solubility of polysulfides seriously hinder the practical application of lithium–sulfur (Li–S) batteries. Therefore, the incorporation of sulfur into carbon-based materials is considered as a suitable solution. Here, a porous pomelo biochar/graphene composite (PBG) was prepared via a simple and green method combining hydrothermal carbonization and KOH activation. The obtained material was used as a host to encapsulate sulfur for the cathode of Li–S batteries, and the three-dimensional pore structure with enhanced conductivity is beneficial for the utilization of sulfur and absorption of soluble polysulfides. As a result, the PBG-S composite (63.3 wt% sulfur) delivered an initial discharge capacity of 1053 mA h g−1 at 0.1C (1C = 1675 mA g−1) and retained 418 mA h g−1 at 3C, even with a high sulfur loading of 4.0 mg cm−2. In addition, the performance of the composite was further improved by reducing the content of sulfur to an appropriate ratio in the PBG-S composite. The optimized PBG-S composite (48.6 wt% sulfur) exhibited a high initial discharge capacity of 1368 mA h g−1 at 0.1C and retained 638 mA h g−1 at 3C, and the discharge capacity remained as high as 664 mA h g−1 and 354 mA h g−1 even after the 200th and 600th cycles at 1C, respectively. The results indicated that PBG, with excellent electrochemical properties, is an ideal electrode material for lithium–sulfur batteries, and can also be prepared economically on an industrial scale.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 3
·1049-1056
·
IF 2.956
Hangxu Guo,Jieru Wang,Denglei Chen,Wei Tian,Shiwei Cao,Desheng Chen,Cunmin Tan,Qihuang Deng,Zhi Qin
Uranium tetraboride (UB 4 ) was successfully synthesized by boro/carbothermal reduction of UO 2 with B 4 C and carbon as combined reduction agents under flowing argon. The effects of processing temperature and mole ratios of starting materials on phase evolution were studied. XRD results demonstrated that UB 4 was obtained with 3.75 mol% B 4 C in excess based on the UO 2 /B 4 C/C molar ratios of 1:1:1 at 1500°C. SEM observation revealed that submicrometer-sized quasi-spherical UB 4 particles cemented together to be an aggregate. The laser particle size analysis showed that the particle size was in the range of 1-10 μm. The oxidation behavior of UB 4 was also investigated by TG and XRD. The oxidation of UB 4 started at about 500°C and it showed better oxidation resistance than other basic uranium nuclear fuels (UO 2 , UC, UN and U 3 Si 2 ). The oxidation chemical process of UB 4 was presented as a three-step process: (a) the formation of U 3 O 8 and B 2 O 3 oxidation products; (b) the formation of UB 2 O 6 intermediate product by the interaction of U 3 O 8 and B 2 O 3 ; (c) the decomposition of UB 2 O 6 to get U 3 O 8 .
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高影响因子
ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Pengcheng Hu,Bolin Li,Chen Bai,Xu Li,Xiaolin Lu
With the rapid development of materials science, on-demand techniques are highly needed with the capability to characterize materials in the micrometer and nanometer scales. In this work, we show that, by employing a prism geometry, total internal reflection sum frequency generation (SFG) vibrational spectroscopy allows for characterizing mesoscopic materials with irregular or complex surfaces. Four representative examples were presented. First, we reveal that mechanical grinding can subtly alter the surface molecular structures of original materials. Second, spin coating can substantially change the surface molecular structures of particle samples. Third, surface restructuring of carboxylated multiwalled carbon nanotubes can happen in response to the surrounding environment. Fourth, surface adsorption and desorption dynamics of toluene on activated charcoal can be traced. Such experiments demonstrate that there are still a broad range of research fields ahead SFG can be directed to, where materials in mesoscopic scales with irregular or complex surfaces can be studied.
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PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Chan Wang,Kuan Hu,Wenjian Li,Huaying Wang,Hu Li,Yang Zou,Chaochao Zhao,Zhe Li,Min Yu,Puchuan Tan,Zhou Li
With the advantages of being lightweight, flexible, and wearable, wire-shaped supercapacitors have received tremendous attention in wearable and portable power sources in recent years. Considering the demands for large-scale applications, it is necessary to explore a facile and convenient preparation approach for wire-shaped supercapacitors. Herein, we reported a simple approach to fabricate wire-shaped electrodes by a dipping method, which possessed a nitric acid-activated graphite fiber core and an activated carbon-coating layer structure. Parallel and symmetric all-solid-state wire-shaped supercapacitors (PWSCs) based on the electrodes were fabricated. The as-fabricated PWSC showed high energy density (6.60 W h/kg, 8.08 mW h/cm, and 1 mV/s) and power density (253 mW/kg, 0.31 mW/cm, and 100 mV/s) and excellent flexibility. Furthermore, this wire-shaped supercapacitor may bring broader application prospects for energy storage devices in future wearable electronic areas.
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PubMed
高影响因子
危险品化学品经营许可证（带存储）