NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 14
·11715-11723
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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
ACS Nano
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2018
·
IF 13.709
Yanan Ma,Yang Yue,Hang Zhang,Feng Cheng,Wanqiu Zhao,Jiangyu Rao,Shijun Luo,Jie Wang,Xueliang Jiang,Zhitian Liu,Nishuang Liu,Yihua Gao
A piezoresistive sensor based on ultralight and superelastic aerogel is reported to fabricate MXene/reduced graphene oxide (MX/rGO) hybrid 3D structures and utilize their pressure-sensitive characteristics. The MX/rGO aerogel not only combines the rGO’s large specific surface area and the MXene’s (Ti3C2Tx) high conductivity but also exhibits rich porous structure, which leads to performance better than that of single-component rGO or MXene in terms of the pressure sensor. The large nanosheets of rGO can prevent the poor oxidization of MXene by wrapping MXene inside the aerogel. More importantly, the piezoresistive sensor based on the MX/rGO aerogel shows extremely high sensitivity (22.56 kPa–1), fast response time (<200 ms), and good stability over 10 000 cycles. The piezoresistive sensor based on the MX/rGO hybrid 3D aerogel can easily capture the signal below 10 Pa, thus clearly testing the pulse of an adult at random. Based on its superior performance, it also demonstrates potential applications in measuring pressure distribution, distinguishing subtle strain, and monitoring healthy activity.
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PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Guozhi Zhu,Song Shi,Meng Liu,Li Zhao,Min Wang,Xi Zheng,Jin Gao,Jie Xu
Porous solid bases are increasingly attractive for applications in green chemistry and heterogeneous catalysis under relatively mild conditions. Here, covalent triazine frameworks (CTFs) were first applied as a support for the porous solid strong bases through a redox process between the base precursor KNO3 and CTFs, leading to a relatively low calcination temperature (400 °C). As a result, porous organic frameworks possessing ordered microstructures as well as strong basic sites were successfully synthesized. The materials were characterized by X-ray diffraction, Fourier transform infrared, high-resolution transmission electron microscopy, temperature programmed desorption of CO2, and so forth. The obtained solid bases displayed remarkable catalytic activity in the aerobic oxidation of methylene compounds, and the yield of fluorenones could reach 93.6% at 120 °C, which was nearly 3 times higher than that of the control catalyst. The current research may present a new idea for the construction of porous organic polymers with strong basicity.
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JOURNAL OF POWER SOURCES
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2018
·
IF 6.945
Jingyi Wu,Hongxia Zeng,Qingxuan Shi,Xiongwei Li,Qing Xia,Zhigang Xue,Yunsheng Ye,Xiaolin Xie
Uncontrollable lithium (Li) dendrite growth has hampered the application of lithium metal batteries (LMBs). Herein, a novel plastic crystal composite polymer electrolyte (nh-CPE) consisting of multifunctional two-dimensional (2D) molybdenum disulfide (MoS 2 ) and ion-conducting one-dimensional (1D) surfactant oxidized cellulose nanocrystal (OCNC) is developed to overcome this challenge. The nh-CPE possesses good Li-dendrite-suppressing ability, which is attributed to the well-designed three-dimensional (3D) ion conducting network constructed by homogeneously dispersed MoS 2 and OCNC. This structure facilitates Li-ion conductivity and enables uniform Li deposition on the anode. Moreover, the impermeable MoS 2 nano-flakes with excellent mechanical strength serve as physical barriers to hold the electrolyte-electrode interface stability and consequently block Li dendrite growth and enhance fire retardancy. When applied in LMB, the nh-CPE exhibits excellent cycle performance and rate capability, with 90% capacity retention after 200 cycles at 0.5 C and 60 °C, and a discharge capacity of 128 mAh g −1 at 1 C. Notably, owing to high room-temperature ionic conductivity (0.8 mS cm −1 ), the cell with nh-CPE cycled at room temperature delivers an initial discharge capacity of 144 mAh g −1 . The outstanding performance and simple process offer great opportunity to promote Li-dendrite-suppressing LMBs for practical application.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2018
·
IF 5.091
Guoqiang Liu,Cuijiao Zhao,Guozhong Wang,Yunxia Zhang,Haimin Zhang
We investigate the possibility of utilizing benzyl alcohol oxidation reaction to replace sluggish oxygen evolution reaction (OER) for the charging process in a rechargeable zinc-air battery , catalyzed by NiCo alloy nanoparticles supported on activated carbon (NiCo/AC) with the multifunctional electrocatalytic activities of the oxygen reduction , oxygen evolution and benzyl alcohol oxidation reactions. As an electrocatalyst for the oxygen reduction reaction (OER), NiCo/AC exhibits superior catalytic activity with an onset potential of 0.85 V ( vs. RHE), a half-wave potential of 0.74 V ( vs. RHE) and a large limiting current density of 4.65 mA cm −2 at 0.2 V ( vs. RHE). Moreover, NiCo/AC also demonstrates the electrocatalytic oxidation activities toward water and benzyl alcohol, moreover, the benzyl alcohol oxidation reaction is more thermodynamically and kinetically favourable with 254 mV smaller overpotential than water oxidation at 10 mA cm −2 . Owing to these advantages, NiCo/AC as air cathode material is assembled into a home-made rechargeable zinc-air battery, resulting an almost 200 mV lower charging voltage at the current density of 50 mA cm −2 in the presence of 0.1 M benzyl alcohol compared to the battery without benzyl alcohol, consequently obtaining 10.5% energy saving at the charging current density of 50 mA cm −2 with high durability.
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Small
·
2018
·Vol. 14
·期 36
·1801953
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IF 9.598
Ruoyu Fan,Chun Chen,Miaomiao Han,Wanbing Gong,Haimin Zhang,Yunxia Zhang,Huijun Zhao,Guozhong Wang
Highly dispersed copper nanoparticles (Cu NPs) supported on activated carbon (AC) are effectively synthesized by one-pot carbothermal method at temperature range of 400–700 °C. The X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis reveal that Cu NPs with diameters of 20–30 nm are evenly anchored in carbon matrix. The 15 wt%-Cu/AC-600 catalyst (derived at 600 °C) exhibits best bifunctional catalysis of aqueous-phase hydrodeoxygenation (HDO) and organic-phase transfer-hydrogenation reaction (THR) to selectively transform vanillin to 2-methoxy-4-methylphenol (MMP). In HDO of vanillin, the as-prepared catalyst achieves a 99.9% vanillin conversion and 93.2% MMP selectivity under 120 °C, 2.0 MPa H 2 within 5 h. Meanwhile, near-quantitative vanillin conversion and 99.1% MMP selectivity are also obtained under 180 °C within 5 h in THR of vanillin by using 2-propanol as hydrogen donor. The transforming pathways of vanillin are also proposed: vanillin is transformed into MMP via intermediate of 4-hydroxymethyl-2-methoxyphenol in HDO case and by direct hydrogenolysis of vanillin in THR course. More importantly, the activity and the selectivity do not change after 5 cycles, indicating the catalyst has excellent stability. The Cu-based catalyst is relatively cheap and preparation method is facile, green, and easy scale-up, thus achieving a low-cost transformation of biomass to bio-oils and chemicals.
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MINERALS ENGINEERING
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2018
·
IF 2.707
Baijun Yan,Daya Wang,Liushun Wu,Yuanchi Dong
Stone coal, a kind of important vanadium-bearing resources in China, accounts for about 87% of the domestic reserves of vanadium. But the currently developed techniques to extract vanadium from stone coal are all confronted with environmental problems. For example, large quantities of caustic or greenhouse gases discharged in the oxidizing roast process, enormous consumptions of acid or alkali in the leaching step and massive tailings containing toxic V 5+ ions. With a view to solve those problems, an innovative process for pre-concentration of vanadium from stone coal was designed and confirmed on a laboratory scale. The distinct features of this design are as follows. Firstly, the environment-friendly Fe 2 O 3 is selected as a capturer of vanadium. Secondly, the natural reducing property of stone coal is utilized to promote the formation of magnetic V-rich phase, Fe 2 VO 4 . Thirdly, a high-grade vanadium concentrate is obtained by magnetic separation method. The practicability of this design was confirmed using industrial stone coal on a laboratory scale. When 10 mass% Fe 2 O 3 relative to stone coal was added and roasted at 1200 °C for 3 h, a high-grade concentrate containing vanadium higher than 14 mass% was obtained, and more than 91% of the total vanadium in stone coal was recovered.
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CELLULOSE
·
2018
·Vol. 25
·期 6
·3459-3469
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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
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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ChemSusChem
·
2018
·Vol. 11
·期 13
·2130-2137
·
IF 7.411
Kai Yao,Zhanwei Xu,Zhi Li,Xinyue Liu,Xuetao Shen,Liyun Cao,Jianfeng Huang
Graphical Letting steam do the work : A grain-like MoS 2 is synthesized by sulfiding MoO 3 using a highly concentrated sulfur vapor. MoS 2 grows epitaxially on three lattice planes, giving rise to particulate MoS 2 coated with MoS 2 nanosheet. Such an architecture gives rise to good dispersity and sufficient distance between neighbors to accommodate the volume change associated with sodiation/desodiation and exhibits a high and stable capacity when used in a sodium-ion battery. MoS 2 is a promising anode material for sodium-ion batteries (SIBs) due to its attractive theoretical capacity and low cost. MoS 2 generally presents a sheet-like structure based on its (002) lattice plane; however, such a structure tends to result in agglomeration and stacking of the sheets that cannot accommodate volume expansion, resulting in poor cyclability. Herein, grain-like MoS 2 particulates (G-MoS 2 ) are synthesized by sulfiding MoO 3 in highly concentrated sulfur vapor, which results in epitaxial growth of MoS 2 in (002), (100), and (110) lattice planes, with the product consisting of MoS 2 particulates of about 300 nm coated with few-layered MoS 2 nanosheets. The unique G-MoS 2 architecture ensures good dispersion and sufficient distance to accommodate volume expansion during sodiation/desodiation, which effectively prevents stacking of MoS 2 , maintaining structural stability. When employed as the working electrode for SIB, G-MoS 2 delivers a high reversible capacity of 324 mAh g −1 at 0.5 A g −1 , retaining 312 mAh g −1 over 300 cycles with an average coulombic efficiency of 99.8 %. Even when G-MoS 2 is cycled at a high current density (2.0 A g −1 ), the retained capacity is 175 mAh g −1 after 400 cycles. Comparison with literature reveals that these capacities are among the more promising reversible values reported for pure MoS 2 .
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FUEL
·
2018
·
IF 4.908
Fei Wang,Junming Xu,Jianchun Jiang,Peng Liu,Fanglin Li,Jun Ye,Minghao Zhou
Catalysts were prepared and utilized in the hydrotreatment of vegetable oil and FAME to produce diesel-like hydrocarbons. Mo 2 C/AC catalyst displayed the higher catalytic activity with 100.00% conversion and 21.01% cracking ratio, compared to MoO/Al 2 O 3 (85.64%, 25.79%), MoS 2 /Al 2 O 3 (83.46%, 11.88%), Mo/Al 2 O 3 (67.99%, 33.19%), NiP/Al 2 O 3 (48.72%, 3.49%), Ni/Al 2 O 3 (18.12%, 0.00%), and MoO/AC (56.05%, 18.55%). The reaction condition was also optimized, and the bio-diesel achieved 100.00% conversion, 9.67% cracking ratio and 0.73 HDO/DC ratio over Mo 2 C/AC under the optimal condition. The conversion over Mo 2 C/AC dropped from 100.00% to 87.08% and 71.06% with cycles. The results of XRD , XPS and N 2 adsorption–desorption demonstrated that the coke deposited on the surface of catalyst and the formation of MoO 2 and MoO 3 led to the deactivation. After regeneration, the catalyst recovered and achieved 99.36% conversion.
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FUEL
·
2018
·
IF 4.908
Yaqiu Tao,Lulu Tao,Zhigang Pan,Simin Qiu,Xiaodong Shen
Formic acid is a promising hydrogen storage material for its high H 2 capacity, easy transfer and moderate H 2 regeneration conditions. Active carbon supported Mo 2 C with or without Co doping were used as the heterogeneous catalyst in the decomposition of a high concentrated aqueous solution of formic acid up to 50% on a fixed bed reactor. For a given flow rate and reaction temperature, though higher volume of H 2 is produced per unit time, the increase in formic acid’s concentration reduces both H 2 selectivity and formic acid conversion rate. At 250 °C, a stream of 236 mL/min H 2 was generated continuously at a high H 2 selectivity (91%) and formic acid conversion rate (86%), from a 10% formic acid fed at the flow rate of 5 mL/min. High reaction temperature improved the conversion of formic acid feed at little expense of H 2 selectivity. The doping of Co in the Mo 2 C lattice improves the H 2 selectivity to 100% at 100–200 °C. A life time study showed the stability of this system by the remained high H 2 selectivity in formic acid decomposition. This work of using active carbon supported molybdenum carbides and high concentrated aqueous formic acid, opens up a new route for the portable H 2 generator using formic acid as a hydrogen storage material at no environmental risk.
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