Crystals
·
2022
·Vol. 12
·期 2
·163
·
IF 2.67
Xiangshen Meng,Jian Li,Yueqiang Lin,Xiaodong Liu,Jianwei Zhao,Decai Li,Zhenghong He
The electro-optical features of the PDLC films applied with a low-frequency square wave voltage were investigated. The transmittance curves indicated the double frequency of the applied voltage at 0–50 Hz, which resulted from the relaxation of an internal electric field polarized by ions in LC droplets. When the local electric field was reversed, the internal polarization electric field could be maintained and superimposed on the local electric field. The relaxation of the internal polarized electric field resulted in the relaxation of the transmittance. Furthermore, the transmittance curves changed with the frequency of the applied voltage.Keywords:PDLC;ion;square-wave voltage;effective electric field
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 4
·522
·
IF 4.146
Fangchao Li,Bin Liu,Yuanhao Shen,Jie Liu,Cheng Zhong,Wenbin Hu
Palladium catalysts have attracted widespread attention as advanced electrocatalysts for the formic acid oxidation (FAO) due to their excellent electrocatalytic activity and relatively high abundance. At present, electrodeposition methods have been widely developed to prepare small-sized and highly-dispersed Pd electrocatalysts. However, the customary use of surfactants would introduce heterogeneous impurities, which requires complicated removal processes. In this work, we reported a two-step electrochemical method that employed square-wave potential treatment (SWPT) to modify electrodeposited Pd particles without the use of capping agents. Under the SWPT with a mixed frequency, Pd particles show significantly reduced size and more dispersed distribution, exhibiting a high mass activity of 1.43 A mg−1toward FAO, which is 4.6 times higher than the counterpart of commercial Pd/C. The increase in electrocatalytic activity of FAO is attributed to the highly developed surface of palladium particles uniformly distributed over the support surface.Keywords:Pd nanoparticles;formic acid oxidation;electrocatalysis;square-wave potential treatment
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
K.M. Wang,J. Shu,S.J. Wang,T.Y. Hong,X.P. Xu,H.Y. Wang
Anode passivation is still a main challenge for the electrochemical generation of ferrate(VI, Fe(VI)), leading to the reduction of Fe(VI) production efficiency. In this study, cyclic voltammetry, scanning electronic microscopy, and electrochemical impedance spectroscopy were used to select better anode electrode configurations (iron wire, iron gauze, and iron coil). The results indicate that iron coil had the least degree of passivation. Different imposed current waveforms during the electrochemical generation of Fe(VI) were also investigated, and the iron coil imposed with square alternating current (AC) wave can mitigate the anode passivation, resulting in higher Fe(VI) production efficiency. The optimum conditions for the electrochemical generation of Fe(VI) were evaluated and the optimum temperature (40 ℃), current density (10 mA/cm 2 ), AC cycle period (15 s) and electrolyte concentrations (14 M NaOH) were identified. As a result, 0.12 mol/L Fe(VI) concentration and over 50% of current efficiency can be achieved after 3 h electrolysis. The generated Fe(VI) solution was further applied to oxidize doxycycline(DOX) and sulfadiazine(SDZ) as typical antibiotics. Over 80% of DOX can be removed at a Fe(VI) to DOX molar ratio of 5:1 (pH = 4–9), whilst a higher Fe(VI) to SDZ molar ratio of 20:1 (pH = 7) was needed to obtain 75% SDZ removal.
研究领域:
环境科学
·
电化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Engineering
·
2022
·
IF 12.834
Boyuan Xue,Qian Yang,Kaidong Xia,Zhihong Li,George Y. Chen,Dayi Zhang,Xiaohong Zhou
Heavy metals, notably Pb 2+ and Cu 2+ , are some of the most persistent contaminants found in groundwater. Frequent monitoring of these metals, which relies on efficient, sensitive, cost-effective, and reliable methods, is a necessity. We present a nanocomposite-based miniaturized electrode for the concurrent measurement of Pb 2+ and Cu 2+ by exploiting the electroanalytical technique of square wave voltammetry. We also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous NiO on a three-dimensional nickel foam, which is then electrochemically seeded with gold nanoparticles (AuNPs). The meticulous design of a low-barrier Ohmic contact between mesoporous NiO and AuNPs facilitates target-mediated nanochannel-confined electron transfer within mesoporous NiO. As a result, the heavy metals Pb 2+ (0.020 mg·L −1 detection limit; 2.0–16.0 mg·L −1 detection range) and Cu 2+ (0.013 mg·L −1 detection limit; 0.4–12.8 mg·L −1 detection range) can be detected simultaneously with high precision. Furthermore, other heavy metal ions and common interfering ions found in groundwater showed negligible impacts on the electrode’s performance, and the recovery rate of groundwater samples varied between 96.3% ± 2.1% and 109.4% ± 0.6%. The compactness, flexible shape, low power consumption, and ability to remotely operate our electrode pave the way for onsite detection of heavy metals in groundwater, thereby demonstrating the potential to revolutionize the field of environmental monitoring.
研究领域:
环境科学
·
分析化学
·
纳米材料
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2016
·
IF 4.035
Qinqin Wang,Lu Wang,Gaiping Li,Baoxian Ye
Palladium nanoparticles with diameter of around 5–10 nm supported on poly (diallyldimethylammonium chloride) (PDDA)-functionalized graphene composites were prepared by a simple chemical method. As-prepared nanocomposites were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), ultraviolet-visible spectrophotometry (UV–vis) and electrochemical techniques, which were clearly demonstrated that palladium nanoparticles were uniformly dispersed on the graphene sheets. Based on the PDDA-Gr-Pd nanocomposites, a new voltammetric sensor was established and exhibited excellent electrocatalytic activity and fast electron transfer rate toward taxifolin . Under the optimal conditions, a lower detection limit of 1×10 −9 mol L −1 (S/N=3) and a wide linear detection range from 4×10 −8 to 1×10 −6 mol L −1 were achieved by square wave voltammetry (SWV). The proposed method was successfully applied for determination of taxifolin in fructus polygoni orientalis with well results.
研究领域:
分析化学
·
材料科学
·
药物分析
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Daixiong Zhang,Qing Xiang
In this work, a Sn-Bi film was successfully fabricated via the electrophoretic deposition (EPD) of nano-Sn powders and nano-Bi powders in an ethanol dispersion medium. Study on film composition showed that a coefficient of proportionality between the mass ratio in the deposited film and that in the suspension was observed for the EPD of Sn-Bi, which controlled the composition of the Sn-Bi film. Therefore, Sn-Bi films with different mass ratios were designed with this linear relationship for the codetection of Cd(II) and Pb(II). Square-wave anodic stripping voltammetry (SWASV) measurements using an in-situ plating strategy were performed after the electrochemical oxidation of Sn and Bi at 0.3 V for 120 s, and the results indicated that the Sn-Bi film with a mass ratio of 0.75 had the best determination ability.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Hui Li,Jie Zhao,Shifan Zhao,Guofeng Cui
Developing a reliable, sensitive and portable electrochemical sensor for precise determination of trace heavy metal ions in water is an attractive challenge. In this work, an integrated three-electrode sensor based on screen–printed gold working electrode (SPAuE) ex-situ electroplated bismuth film was developed via a facile and simple process for the determination of trace Pb(II), Cd(II), and Zn(II) by square wave anodic stripping voltammetry (SWASV). The bismuth film was deposited on SPAuE at a potential of −0.08 V (Bi/SPAuE −0.08V ). The results exhibited the sensor with a wide linear range (from 1 to 120 μg L -1 ) for the simultaneous detection of these three heavy metal ions. Besides, the detection limits of Pb(II), Cd(II), and Zn(II) for the sensor were respectively found to be 0.04 μg L −1 , 0.02 μg L −1 , and 0.05 μg L −1 (S/N = 3). The proposed sensor revealed good anti-interference ability, satisfactory repeatability with RSDs of less than 2.5% (n = 12), excellent reproducibility with RSDs of less than 2.5% (n = 6), and considerable stability. The detection accuracy of the Bi/SPAuE −0.08V based sensor was further evaluated via atomic absorption spectroscopy (AAS). Due to its simplicity in process, high detection performance and excellent reliability, such sensors are expected to find utility in portable heavy metal detection applications.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2017
·Vol. 33
·期 5
·799-803
·
IF 1.024
Cui Wenyu,Fan Lishuang,Geng Lin,An Maozhong,Zhang Fujun
The use of a digital versatile disc(DVD)-based Ag electrode for the square-wave anodic stripping voltammetric determination of Pb 2+ and Cd 2+ was described. The effect of I – on the stripping analysis of Pb 2+ and Cd 2+ at Ag electrodes was first studied. I – significantly improved the stripping peaks of both Pb 2+ and Cd 2+ . The square-wave voltammetric stripping response was linear over 5―50 μg/L for Pb 2+ and Cd 2+ with a deposition time of 118 s. The detection limits were 0.2 and 2.6 μg/L for Pb 2+ and Cd 2+ , respectively. The high sensitivity, selectivity, and stability of this DVD-based Ag electrode enabled its practical application for simple, rapid and economical determination of trace levels of Cd 2+ and Pb 2+ in tap water samples. In addition, detection can be achieved without sample deoxygenation and the electrode can be easily manufactured.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2019
·Vol. 166
·期 12
·B1028
·
IF 3.12
Dandan Hu,Yufang Hu,Qingqing Zhang,Pingjian Ran,Xinda Liu,Yudi Zheng,Zhiyong Guo,Sui Wang,Di Wu
Monitoring DNA-related enzymes activity precisely and reliably is absolutely vital to better grasp their roles in the initiation and progression of cancer, thus further exploring their functions in cancer diagnosis and treat. Here, we establish a label-free electrochemical biosensor for investigating both terminal deoxynucleotidyl transferase (TdT) and exonuclease I (Exo I) activity by silver-based square wave stripping voltammetry (SWV). The strategy is achieved by two attractive points in design: a TdT-derived enzymatic synthesis of randomly arrayed C-rich DNA sequence and an Exo I-guided enzymatic degradation. This C-rich DNA-templated silver nanoclusters (AgNCs) serve as the electrochemical signal probe, and a signal on-off modulated process is displayed for the existence of TdT and Exo I, respectively. On account of AgNCs-based square wave stripping voltammetry, testing TdT has a linear concentration range of 0.001 to 5 U/mL with a detection limit of 0.00044 U/mL (S/N = 3). Additionally, Exo I with a detection limit of 0.027 U/mL (S/N = 3) can be analyzed with a linear range of 0.1 to 500 U/mL. The real application of the proposed method in their inhibitors screening is also discussed well. The biosensor provides a powerful idea for the ultrasensitive bio-analysis and shows broad clinical application prospect.
研究领域:
生物化学
·
分析化学
·
医学诊断
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL LETTERS
·
2022
·
IF 2.267
Lan Yang,Leilei Sun,Jie Song,Xueliang Zhao,Xicai Pan,Zeming Wu,Qingyun Cai
The motivation of this work is to develop a simple method for the on-site detection of total arsenic at the ppb level. For this purpose, novel nano-coral gold (NCG) was fabricated using NH4Br to lead the growth of Au along a definite direction on a gold substrate. Square wave anodic stripping voltammetry (SWASV) was used for the determination of arsenic in industrial water with a NCG working electrode. Due to the high specific surface area and nano-structure of the nano-coral gold, high sensitivity was achieved with a limit of detection (LOD) of 0.4 ppb. 3.2 ppb arsenic was determined in industrial water. The detectable arsenic concentration is far below the regulatory limit of 10 ppb by the World Health Organization (WHO). Across the As (III) linear range from 2.5 to 100 ppb, the sensor response is stable, reproducible, and linear with concentration.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Yajing Zhang,Hui Wang,Zhaoyong Bian
Currently, using electrochemical precipitation techniques for phosphate removal and recovery in hydroxyapatite (HAP) or calcium phosphate (CaP) form is widely used, while the high energy consumption of electrochemical precipitation is a major obstacle to its application. In this study, a square wave pulsed electrochemical phosphate precipitation method was developed, which achieved phosphate pollution control and phosphate resource recovery and reuse at the same time. The square wave pulsed electrochemical phosphate recovery system was constructed and a Pt-rGO/CuF electrode was synthesized and evaluated. This result indicated that the Pt-rGO/CuF electrode had the highest electrocatalytic activity, the better electrical conductivity, and the smallest electron transport barrier. Under optimal operation conditions, the phosphate removal efficiency and specific energy consumption of Pt-rGO/CuF were 64.2% and 21.49 kWh kg −1 , respectively. The Pt-rGO/CuF electrode demonstrated the best electrochemical precipitation reaction performance. The Pt-rGO/CuF electrode was applied to multiple types of actual wastewater, and the results showed that it has better application prospects in both low (7.75 mg L −1 ) and high (66 mg L −1 ) phosphate concentration wastewater, the phosphate removal efficiency was 75.5% and 59.1%, respectively. Compared with traditional chemical precipitation , the electrochemical precipitation method saved $2.88 per kg P and $57.57 per kg P, respectively.
研究领域:
环境科学
·
电化学工程
✓ 已验证
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 22
·5102
·
IF 3.057
Luyi Huang,Yoshikazu Ito,Takeshi Fujita,Xingbo Ge,Ling Zhang,Heping Zeng
Heavy metals pollution is one of the key problems of environment protection. Electrochemical methods, particularly anodic stripping voltammetry, have been proven a powerful tool for rapid detection of heavy metal ions. In the present work, a bismuth modified porous graphene (Bi@PG) electrode as an electrochemical sensor was adopted for the detection of heavy metal Cd2+in an aqueous solution. Combining excellent electronic properties in sensitivity, peak resolution, and high hydrogen over-potential of bi-continuous porous Bi with the large surface-area and high conductivity on PG, the Bi@PG electrode exhibited excellent sensing ability. The square wave anodic stripping voltammetry response showed a perfect liner range of 10−9–10−8M with a correlation coefficient of 0.9969. The limit of detection (LOD) and the limit of quantitation (LOQ) are calculated to be 0.1 and 0.34 nM with a sensitivity of 19.05 μA·nM−1, which is relatively excellent compared to other carbon-based electrodes. Meanwhile, the Bi@PG electrode showed tremendous potential in composite detection of multifold heavy metals (such as Pb2+and Cd2+) and wider linear range.Keywords:porous materials;graphene;bismuth;electrochemical deposition;square wave anodic stripping voltammetry
研究领域:
环境科学
·
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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