Materials Chemistry Frontiers
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2020
·Vol. 5
·期 3
·1324-1329
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IF 6.788
Songjie Wang,Yongyin Liang,Wenchen Zhuo,Hang Lei,Muhammad Sufyan Javed,Botian Liu,Zilong Wang,Wenjie Mai
To meet the increasing requirement of flexible energy storage devices, it is critical to develop an electrode with commercial-level mass loading of active material for supercapacitors. Herein, we fabricated a high mass loading and freestanding CNT@PPy electrode (6.07 mg cm−2) by a simple vacuum filtration and low-temperature polymerization method. Moreover, owing to the high conductivity of CNT fiber networks offering a fast electron transporting passage, the optimized CNT@PPy electrode exhibits a prominent areal capacitance (2.6 F cm−2) with significantly improved mechanical properties (its ultimate tensile strength is 20.7 MPa, 23 times higher than that of pure CNT film). The freestanding all-solid-state symmetric supercapacitor based on the optimized CNT@PPy electrode obtains a high power density of 0.64 mW cm−2 at an energy density of 76.7 μW h cm−2.
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JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2020
·Vol. 101
·期 6
·2552-2560
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IF 2.614
Hengye Chen,Liuna Wei,Xiaoming Guo,Chengying Hai,Lu Xu,Lei Zhang,Wei Lan,Chunsong Zhou,Yuanbin She,Haiyan Fu
BACKGROUND The quality of tea is influenced by numerous factors, especially l- theanine, which is one of the important markers used to evaluate the sweetness and freshness of tea. Sensitive, rapid, and accurate detection of l -theanine is therefore useful to identify the grade and quality of tea. RESULTS A high-sensitivity, paper-based fluorescent sensor combined with chemometrics was established to detect l- theanine in tea water based on CdTe quantum dots / corn carbon dots and nano tetra pyridel-porphine zinc (ZnTPyP). To verify the reliability of this method, fluorescence spectra and fluorescence-visualized paper-based sensors were compared. The fluorescence spectrum method demonstrated a linear range of 1 to 10 000 nmol L −1 and a limit of detection (LOD) of 0.19 nmol L −1 . In the fluorescence-visualized paper-based sensors there was a linear range of 10–1000 nmol L −1 , and the LOD was 10 nmol L −1 . Partial least squares discriminant analysis (PLSDA) and partial least squares regression analysis (PLSR) were used successfully to determine l -theanine accurately in tea water with this approach. The accuracy of the PLSDA model was 100% both in the training set and the predicting set, and the correlation coefficient between the actual concentration and the predicted concentration was greater than 0.9997 in the PLSR model. CONCLUSION This fluorescence-visualized paper-based sensor, combined with chemometrics, could be applied efficiently to the practical analysis of tea water samples, which provides a new idea to ensure the flavor and quality of tea. © 2020 Society of Chemical Industry
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PLoS One
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2020
·Vol. 15
·期 10
·e0240173
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IF 2.74
Lei Zhang,Zhengying Wei,Pengcheng Liu
To improve the single-layer all-solid-state ion selective electrode’ defects including poor conductivity of PVC sensitive membrane and interference of water layer between substrate electrode and sensitive membrane, a double-layer all-solid-state ion selective electrode with nanomaterial as the solid contact layer and conductive polymer as the ion sensitive membrane was developed. A gold nanoparticles solid contact layer and a nitrate-doped polypyrrole molecularly imprinted polymer membrane were prepared by electrodeposition. The optimal parameters obtained by electrochemical performance test were 2.5 mmol/L HAuCl 4 electrolyte for solid contact layer and 1800s electrodeposition time for sensitive membrane. The new electrode exhibited a Nernstian response of -50.4 mV/decade and a low detection limit of 5.25×10 -5 mol/L. Potentiometric water layer test showed no water film formed between the gold nanoparticles solid contact layer and nitrate-doped polypyrrole molecularly imprinted polymer membrane. The contact angle between droplet and the surface of solid contact layer was 112.35° and showed good hydrophobic property. Furthermore, the developed electrode exhibited fast response, excellent potential stability and long lifetime. This electrode is suitable for the detection of nitrate concentration in water and liquid fertilizer.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
·
IF 4.939
Jian Zhang,Shiyu Liu,Hao Wang,Qibin Xia,Xiaoxi Huang
The application of electrochemical water splitting process in acidic medium is restricted by the lack of highly efficient and stable oxygen evolution reaction (OER) electrocatalyst . In this work, we report a facile soft template method to synthesize nanosized iridium oxide for electrocatalytic OER in acidic medium. The fabrication process involves thermal treatment of iridium complex and polypyrrole in air. The compositions and structures of the resulting catalytic materials are significantly influenced by the annealing temperature. The nanostructured iridium oxide synthesized at optimal 450 °C exhibits low overpotential (291.3 ± 6 mV) to reach 10 mA/cm 2 current density towards OER, which is better than the commercial iridium oxide. Further investigation indicates that nanosized iridium oxide synthesized at 450 °C has high electrochemical active surface area to expose abundant accessible active sites, which can accelerate the OER rate. This method can also provide new guidance to prepare other metal oxide nanoparticles for various applications.
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CELLULOSE
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2020
·Vol. 27
·期 16
·9457-9466
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IF 4.21
Hou Minjie,Hu Yumeng,Xu Miaojun,Li Bin
A novel conductive film with a sandwich structure was successfully prepared from nanofibrillated cellulose (NFC) and carbon nanotubes (CNTs). This film possessed an anisotropic electrical conductivity, and its electrical conductivity and mechanical strength were significantly enhanced. The electrical conductivity of the film was as high as 90.8 S cm −1 and the tensile strength was 60.8 MPa when the CNT loading amount was 19.2 wt%. Based on this unique structure, this flexible conductive film was used to prepare an all-in-one integrated film supercapacitor (IFSC) though a simple electrodeposition method. After the liquid electrolyte penetrated into the composite film, the flexible IFSC possessed a high volumetric capacitance of 11.25 F cm −3 and retained stable electrochemical performance under different bending states. Therefore, we believed that the flexible and simply designed NFC based film was a promising candidate for the application in wearable bio-electronics.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Peng Lv,Lingxia Song,Yue Li,Hao Pang,Weiqu Liu
The rapid development of the portable and wearable devices has inspired the ever-growing pursuit of flexible energy storage equipment which can power these devices. Here, rice paper (RP) was integrated with a homemade LGS-polypyrrole (LGS-PPy) ink and commercial pen ink in order to construct a flexible electrode of a supercapacitor via a facial dip-coating method. The obtained RP/LGS-PPy ink/Pen ink composites showed a high areal specific capacitance of 1568 mF/cm 2 at 0.2 mA/cm 2 , owing to the uniform deposition of a LGS-PPy layer which was covered by the pen ink coating. Furthermore, the assembled symmetric supercapacitor fabricated from the RP/LGS-PPy ink/Pen ink electrode exhibited impressive electrochemical performances in terms of specific capacitance (317.5 mF/cm 2 at 2 mA/cm 2 ), power density (846 μW/cm 2 at the energy density of 23.5 μWh/cm 2 ), and life times (82.1% capacitance retention after 5000 cycles). In addition, the capacitance of the as-prepared device remained essentially unchanged even after bending at 180°, thus demonstrating this device's outstanding flexibility. The low cost of raw materials, robust fabrication strategy as well as the moderate performances make the RP-based supercapacitor a promising candidate for future flexible energy storage devices.
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MICROCHIMICA ACTA
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2021
·Vol. 188
·期 1
·1-12
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IF 5.833
Yang Lili,Wang Jiasheng,Lü Haitao,Hui Ni
A dual-sensing platform is proposed based on multi-walled carbon nanotubes/Prussian blue–functionalized polypyrrole nanowire array (PPY/MWCNTs/PB). Highly aligned PPY nanowire arrays were electrochemically prepared on the surface of glassy carbon electrodes, which were doped with MWCNTs/PB nanocomposites. The nanomaterial combines the characteristics of the PPY nanowires (high conductivity and large specific surface area) and MWCNTs/PB (excellent catalytic performance and intrinsic redox activity). Owing to the nanowire microstructure and outstanding electrical properties, the PPY/MWCNTs/PB nanowire arrays show excellent electrocatalysis of the reduction of hydrogen peroxide and facilitate the construction of a high-performance biosensing platform for microRNA (miRNA). A linear relationship between analytical signal and concentration of hydrogen peroxide and miRNA was obtained in the range 5 to 503 µM (1.4–5.1 mM) and 0.1 pM to 1 nM, and detection limits of 1.7 μM and 33.4 fM, respectively. This new supersensitive sensing platform has broad application prospects of biomolecule and other analyte determination in drug, biomedical, plant protection, and environmental analysis. Graphical abstract
Prussian blue/multi-walled carbon nanotubes functionalized polypyrrole nanowire arrays (PPY/MWCNTs/PB) were prepared by a facile one-step electrochemical method. PPY/MWCNTs/PB nanowire arrays show excellent electrocatalysis of the reduction of H 2 O 2 and facilitate the construction of a high-performance biosensing platform for microRNA.
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RSC Advances
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2021
·Vol. 11
·期 2
·1109-1114
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IF 3.361
Peng Lv,Yeyun Meng,Lingxia Song,Hao Pang,Weiqu Liu
A robust self-supported electrode based on nanocellulose fibers (CNF), multi-walled carbon nanotubes (CNT), and polypyrrole (PPy) was prepared by a facile combination of ultrasonic dispersion and consequent in situ polymerization. In addition, the feasibility of utilizing this ternary composite as an electrode for supercapacitors was studied. The results revealed that the obtained CNF/CNT/PPy composite exhibited a large specific capacitance of 200.8 F g−1 at 0.5 A g−1. Equally important, the electrode capacitance retained about 90% of its initial value after 5000 charge/discharge cycles at a current density of 1 A g−1, which thus demonstrated its excellent cycling stability. The simple integration route and outstanding electrochemical properties distinguish this new composite as a prospective candidate for use as a high-performance electrode in supercapacitors.
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CHEMICAL ENGINEERING SCIENCE
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2020
·
IF 3.871
Yaju Chen,Qinggang Ren,Xiaojing Zeng,Leiming Tao,Xiantai Zhou,Hongbing Ji
Multifunctionalization of porous organic polymers (POPs) for working in concert on a substrate is now a research topic in CO 2 catalysis, yet it remains challenging. This work describes a pre- and post-synthetic strategy to design metalloporphyrin-based azo-hierarchical porous ionic polymers (ZnTPP/QA-azo-PiPs), which were synthesized based on diazo-coupling reaction of tetra(4-aminophenyl) porphyrin zinc with tri/diphenols in aqueous solution under mild conditions, followed by etherification with quaternary ammonium bromide. This synthetic approach endows ZnTPP/QA-azo-PiP 1 with features of an improved surface area (181 m 2 /g), hierarchical porosity, and high-density active sites. ZnTPP/QA-azo-PiP 1 presented a noteworthy CO 2 uptake of 1.77 mmol/g at 273 K and 1.0 bar and good CO 2 /N 2 selectivity of 44.8. As expected, ZnTPP/QA-azo-PiP 1 showed quantitative conversion and selectivity for a range of epoxides under mild conditions (1.0 MPa, 80 °C, 12 h) in the CO 2 cycloaddition reaction. ZnTPP/QA-azo-PiP 1 could been recycled easily and retained complete retention of activity and selectivity for over 7 cycles. Moreover, with efficacious activity in conversion of diluted CO 2 (15% CO 2 in 85% N 2 , v/v), ZnTPP/QA-azo-PiP 1 could smoothly catalyze CO 2 -involved reaction to produce oxazolidinones and N-formylated amines under mild conditions. This work promotes sustainable synthesis of advanced multifunctional POPs and gives great promise for their application in synthetic transformations of CO 2 .
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ELECTROCHEMISTRY COMMUNICATIONS
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2020
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IF 4.333
Jihuai Wu,Shaoyun Wu,Weihai Sun
A polyoxometalate (H 3 PW 12 O 40 , PW 12 )-doped polypyrrole (PW 12 -PPy) hybrid film was successfully prepared by electropolymerization. The PW 12 -PPy composite film was used as an efficient Pt-free counter electrode in a dye-sensitized solar cell (DSSC). The surface appearance, chemical composition and internal phase structure of the samples were investigated by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. Electrochemical impedance spectroscopy and cyclic voltammetry measurements recorded using the prepared electrodes indicate that the PW 12 -PPy electrode has a higher reduction peak current density and a smaller series resistance than the Pt electrode, suggesting that the electrocatalytic activity of the PW 12 -PPy electrode for I 3 − reduction is better than that of the Pt electrode. Under simulated solar irradiation (AM 1.5) with an intensity of 100 mW⋅cm −2 , the DSSC based on the PW 12 -PPy counter electrode produces an average power conversion efficiency (PCE) of 6.19%; this efficiency value is on a par with that of similar devices using Pt as the cathode (6.25%).
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APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
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2020
·Vol. 126
·期 12
·1-7
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IF 1.81
He Song,Chang Mengyu,Liu Pengcheng,Wang Xueqin,Bai Zhongchen
We studied a Surface-enhanced Raman scattering (SERs) film by self-assembled deposition of Ag nanoparticles on the surface of PPy@PEDOT:PSS films to detect melamine molecules. The PPy@PEDOT:PSS film was prepared using an electrochemical polymerization method in a mixture solution of PPy and PEDOT:PSS. Then, Ag nanoparticles were directly deposited on the surface of PPy@PEDOT:PSS films by a chemical self-assembly method as an active SERs substrate to detect melamine molecules. The results showed that the density of Ag nanoparticles on the surface of PPy@PEDOT:PSS film was gradually increased due to the increase of depositional time of Ag nanoparticles. Accordingly, The SERs effect was also substantially enhanced. The signal of melamine was increased up to 440 times. The melamine molecules at 6.4 ng/ml concentration could be clearly identified. This preparing method of SERs film and detecting method of melamine molecules provide a new strategy for the design and application of chemical sensors and bio-sensors.
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ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Tian Cen,Liang Chen,Xuejun Zhang,Yanhong Tian,Xinxiao Fan
In the study, a novel fiber-shaped asymmetric supercapacitor with high specific capacitance has been successfully constructed by twisting two self-made composite electrodes. Prior to manufacturing these electrodes, carbon nanotube is first deposited on carbon fiber by electrophoretic deposition to obtain carbon fiber/carbon nanotube composites. Subsequently, the positive and negative composite electrodes are prepared by the electrochemical deposition of manganese dioxide and electrochemical polymerization of polypyrrole, respectively. As a result, the novel fiber-shaped asymmetric supercapacitor performs a wide potential window of 1.7 V and a high energy density of 22.8 μWh cm −1 at the current density of 0.5 A g −1 . Meanwhile, it still maintains great capacitance retention of 91.6% and 86.1% from 500 bending repetitions and 5000 cycles, respectively, which is due to the excellent flexibility and long cycle life. It is significant that the promising performance of the novel fiber-shaped asymmetric supercapacitor is of greatly potential for portable and wearable electronics in the future.
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危险品化学品经营许可证（带存储）