ANALYTICAL CHEMISTRY
·
2015
·
IF 5.636
Juan Wei,Zheng Guo,Xing Chen,Dong-Dong Han,Xiang-Ke Wang,Xing-Jiu Huang
Detection of Cr(VI) by electrochemical methods generally focuses on noble-metal-modified electrodes in strong acid solution using voltammetric techniques. In this work, we report a new strategy to detect Cr(VI) as HCrO4– at pH 5.0 in drinking water using electrochemical impedance spectroscopy. The strategy is based on the high-affinity and specific binding of crown ethers (i.e., azacrown) to HCrO4–, which forms sandwich complexes between them via hydrogen bonds and moiety interactions with K+ captured by azacrown on its self-assembled Au electrode surface. This then blocks the access of redox probes (Fe(CN)63–/4–) to the self-assembled Au electrode, further resulting in an increase in the electron transfer resistance. This method offers a detection limit of 0.0014 ppb Cr(VI) with a sensitivity of 4575.28 kΩ [log c (ppb)]−1 over the linear range of 1–100 ppb (R2 = 0.994) at pH 5.0. In addition, the azacrown self-assembled Au electrode has good selectivity for Cr(VI) with good stability and low interferences. This approach can be performed on spiked Cr(VI) as well as real samples. To the best of our knowledge, this is the first example of electrochemical impedimetric sensing that allows ultrasensitive and ultraselective detection of Cr(VI).
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2014
·Vol. 26
·期 1
·369-376
·
IF 1.966
Wang Hongguang,Xiong Xinqian,Xu Jinbao,Wang Lei,Bian Liang,Ren Wei,Chang Aimin
Preferred (100)-oriented and complete (100)-oriented LaMn 0.6 Al 0.4 O 3 thin films were deposited on (100)-LaNiO 3 -coated silicon substrates by spin-coating method. Complex impedance spectroscopy was used to provide a convincing evidence for the existence of grain and grain boundary that were separated in the frequency domain in impedance spectrum. It suggests that the better grain orientation is effective in lowering the resistivity and activation energy but with little influenced on grain boundary. The analysis of impedance dependent on frequency, reveals that the relaxation is a thermally activation process. The grain and grain boundary conduction obey the Arrhenius behavior with activation energy 1.2294–1.3273 eV. The mechanism associated with the change of the electrical properties of the thin films is discussed.
研究领域:
材料科学
·
固体物理
✓ 已验证
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 12
·4288-4295
·
IF 2.305
Zhang Jia-Wei,Li Ying,Ding Yu-Shi,Pan Ke-Feng,Zhao Qing
Poly( o -phenylenediamine) was synthesized in different inorganic acid media, hydrochloric (HCl), nitric (HNO 3 ), and phosphoric acid (H 3 PO 4 ).
The aim was to investigate the protective effect of doped coatings on mild steel in an aggressive environment. The synthesized doped-PoPD products were characterized by x-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, and cyclic voltammetry. The inhibition abilities of doped coatings were evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy in 3.5% NaCl solution. In the present article, the lowest corrosion current and highest protection efficiency of the doped polymer were observed for the polymer synthesized in HNO 3 medium. The results showed that good protection of mild steel can be achieved by PoPD coating doped with inorganic acid in 3.5% NaCl solution.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Fubao Gong,Jun Shen,Runhua Gao,Xiong Xie,Xiong Luo
A novel organic–inorganic Mg(OH) 2 /silane surface layer has been developed for corrosion protection of AZ31 magnesium alloy. The results of electrochemical impedance spectroscopy (EIS), the immersion tests, Fourier-transform infrared spectroscopy (FTIR) and sellotape tests showed that the Mg(OH) 2 /silane-based composite surface layer possessed excellent corrosion resistance and very good adhesion due to the formation of Si–O–Mg bond between Mg(OH) 2 layer and silane layer. Electrochemical impedance spectroscopy tests results indicated that for the long-term corrosion protection of AZ31 the increase of the curing temperature improved the impedance of the composited layer when the curing temperature was lower than 130 °С. However, the impedance of the composited layer deceased when the curing temperature was more than 130 °С due to the carbonization of the silane layer.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 3
·615
·
IF 4.927
Yunxiao Feng,Gang Liu,Ming La,Lin Liu
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro) has been regarded as one of the ideal targets for the development of antiviral drugs. The currently used methods for the probing of Mpro activity and the screening of its inhibitors require the use of a double-labeled peptide substrate. In this work, we suggested that the label-free peptide substrate could induce the aggregation of AuNPs through the electrostatic interactions, and the cleavage of the peptide by the Mpro inhibited the aggregation of AuNPs. This fact allowed for the visual analysis of Mpro activity by observing the color change of the AuNPs suspension. Furthermore, the co-assembly of AuNPs and peptide was achieved on the peptide-covered electrode surface. Cleavage of the peptide substrate by the Mpro limited the formation of AuNPs/peptide assembles, thus allowing for the development of a simple and sensitive electrochemical method for Mpro detection in serum samples. The change of the electrochemical signal was easily monitored by electrochemical impedance spectroscopy (EIS). The detection limits of the colorimetric and electrochemical methods are 10 and 0.1 pM, respectively. This work should be valuable for the development of effective antiviral drugs and the design of novel optical and electrical biosensors.Keywords:SARS-CoV-2 main protease;colorimetry;electrochemical impedance spectroscopy;gold nanoparticles
研究领域:
病毒学
·
分析化学
·
生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2018
·
IF 3.794
Hai Jiang,Xiao-Hong Wang,Wen Lei,Gui-Fen Fan,Wen-Zhong Lu
The effects of two-step sintering on the microstructure, mechanical and thermal properties of aluminum nitride ceramics with Yb 2 O 3 and YbF 3 additives were investigated. AlN samples prepared using different sintering methods achieved almost full density with the addition of Yb 2 O 3 –YbF 3 . Compared with the one-step sintering, the grain sizes of AlN ceramics prepared by the two-step sintering were limited, and the higher flexural strength and the larger thermal conductivity were obtained. Moreover, the electrochemical impedance spectroscopy of AlN ceramic was associated with thermal conductivity by analyzing the defects and impurities in AlN ceramics. The fitting grain resistance and the activation energy for the grain revealed the lower concentrations of aluminum vacancy in the two-step sintered AlN ceramics, which resulted in the higher thermal conductivity. Thus, mechanical and thermal properties for AlN ceramics were improved with Yb 2 O 3 and YbF 3 additives sintered using two-step regimes.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
高影响因子
IONICS
·
2018
·Vol. 24
·期 10
·3287-3290
·
IF 2.347
Zhang Bin,Zheng Yangong,Chen Weiwei,Jian Jiawen
Ionic liquid-gated organic transistors have been reported to have high mobility and low operational voltage; they mainly benefit from the capacitance of electric double layers (EDLs) at the interface of an electrolyte and a semiconductor. Although the capacitance of EDLs is usually considered a fixed value, contrary to the theory of EDLs, EDL capacitance is tunable by the electrode potential. In this study, we prepared organic transistors with ionic liquid mixed with polymer as the dielectric. We found that the conductance parameter of the semiconductor channel decreased with decreasing gate voltage. Then, to examine the changes in interfacial capacitance under various gate voltages, the impedance of the whole transistor was measured, and an equivalent circuit model was applied to extract the differential capacitance. The decreased EDL capacitance with the gate potential is ascribed to the finite ion volume in the ionic liquid gel based on Kornyshev’s theory.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Lu Shen,Yong Li,Wenjie Zhao,Lijing Miao,Weiping Xie,Huanming Lu,Kui Wang
In order to hold the excellent corrosion resistance of zinc-rich epoxy coatings with reduced zinc content, five types of graphene modified zinc-rich epoxy coatings (G-ZRCs) were prepared. The effect of zinc content on the corrosion protection behaviors of G-ZRCs was investigated using electrochemical impedance spectroscopy (EIS). Open circuit potential (OCP) was also utilized to deepen the understanding of the anticorrosion mechanism of the as-prepared composite coatings. The results confirmed that addition of 0.3 wt % graphene could make the coating with 40 wt % (G-40ZRC) and 55 wt % zinc (G-55ZRC) provide cathodic protection for a short period of time. The EIS and OCP results showed a dominant physical barrier protection mechanism for the coatings without zinc (G-ZRC), while there was a mixed mechanism for G-40ZRC and G-55ZRC and a dominant cathodic protection mechanism for the coatings with 70 and 85 wt % zinc (G-70ZRC and G-85ZRC). Furthermore, the graphene modified zinc-rich coatings and corresponding corrosion products immersed in a 3.5% NaCl solution for 100 days were also characterized, which could further reveal anticorrosion mechanisms of the graphene modified zinc-rich coatings and the passivation effect of polyaniline (PANI).
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
CORROSION SCIENCE
·
2021
·
IF 7.205
Tong Liu,Haichao Zhao,Dawei Zhang,Yuntian Lou,Luyao Huang,Lingwei Ma,Xiangping Hao,Liang Dong,Federico Rosei,Woon Ming Lau
Combining a fast self-healing action and a high barrier property remains a challenge in polymeric protective coatings. Herein, we report an intrinsic self-healing epoxy coating in which 2-ureido-4[1H]-pyrimidinone (UPy) as a quadruple hydrogen bonding unit, grafted onto the backbones of an epoxy-matrix by an amine-terminated oligo(propylene glycol) linker. Without any intervention, the epoxy-matrix performs its self-healing function in ∼5 min, even under aqueous immersion. Besides, electrochemical impedance spectroscopy measurements demonstrate corrosion protection ability of such self-healed coating on a steel substrate, with a high |Z| 0.01Hz value of 4.8 × 10 10 Ω·cm 2 after 60 days of immersion in NaCl solution.
研究领域:
材料科学
·
腐蚀与防护
·
高分子化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Shengjie Liang,Mengyuan Hu,Baoe Li,Dan Xia,Chunyong Liang,Feng Peng,Donghui Wang
Bacterial infections around implants constitute a significant cause of implant failures. Early recognition of bacterial adhesion is an essential factor in preventing implant infections. Therefore, an implant capable of detecting and disinfecting initial bacterial adhesion is required. This study reports on the development of an intelligent solution for this issue. We developed an implant integrated with a biosensor electrode based on alternating current (AC) impedance technology to monitor the early growth process of Escherichia coli (E. coli) and its elimination. The biosensor electrode was fabricated by coating polypyrrole (PPy) doped with sodium p-toluenesulfonate (TSONa) on titanium (Ti) surfaces. Monitoring the change in resistance using electrochemical impedance spectroscopy (EIS), combined with an equivalent circuit model (ECM), enables the monitoring of the early adhesion of E. coli. The correlation with the classical optical density (OD) monitoring value reached 0.989. Subsequently, the eradication of bacteria on the electrode surface was achieved by applying different voltages to E. coli cultured on the electrode surface, which caused damage to E. coli. Furthermore, in vitro cellular experiments showed that the PPy coating has good biocompatibility and can promote bone differentiation.
研究领域:
生物医学工程
·
材料科学
·
微生物学
✓ 已验证
DOI
PubMed
高影响因子
Coatings
·
2020
·Vol. 10
·期 2
·128
·
IF 2.436
Qingjun Zhu,Binbin Zhang,Xia Zhao,Binbin Wang
Given the corrosion tendency of the natural oxide film of aluminum alloys, micro arc oxidation (MAO) treatment is used as an efficient and economic method to enhance the corrosion resistance. However, irregular voids, pores, and micro cracks are easily formed during the MAO process, which are harmful to the anti-corrosion property of MAO coatings. In this paper, binary additives of electrolytes, including (NaPO3)6and H3BO3, were used to obtain MAO coatings with improved thickness and compact microstructures on 6061 aluminum alloys. The as-prepared coatings were investigated using a thickness meter, scanning electron microscope (SEM), X-ray diffractometer (XRD), and electrochemical impedance spectroscope (EIS). The results showed that the coordinated influence of the binary additives could change the discharge behaviors and micro morphologies of the MAO coatings compared to the base silicate electrolyte. A thicker and stronger MAO coating could be achieved, which was mainly composed of Al2O3phases. The EIS tests revealed that the corrosion current density of the obtained optimal MAO coating decreased by three orders of magnitude from 1.209 × 10−6A·cm−2to 2.981 × 10−9A·cm−2. We believe that the binary additive-enhanced MAO coatings could provide a promising anti-corrosion solution in various applications.
研究领域:
材料科学
·
表面工程
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2019
·
IF 4.309
Ali Shmshad,Jialun Tang,Imran Muhammad,Dengbao Han,Xin Zhang,Shuai Chang,Qingfan Shi,Haizheng Zhong
Colloidal quantum dots (QDs) are talented materials and have been extensively investigated in the field of photonics and optoelectronics due to their size-dependent optical properties. The core/shell structure of QDs with a wide band gap shell has been adopted for obtaining stable emission and high photoluminescent (PL) quantum efficiency. However, when employed in active devices such as light-emitting diodes (LEDs), the thick-shell structure of QDs may impede the transportation of carriers, thus deteriorating the device performance. In this work, the effect of the shell thickness of CdSe/ZnS QDs on the device performance is systematically studied through impedance spectroscopy, by constructing the electron-only symmetric device architecture. It is found that the evolution of capacitance in the symmetric device under applied voltage reflects the charge accumulation within the device and predicts the LED performance. The lowest capacitance is evaluated in the symmetric device containing QDs with a medium shell size of 2.1 nm, showing improved performance in the LED with the highest luminance and current efficiency of 26 370 cd/m2 and 8.3 cd/A, respectively.
研究领域:
光子学
·
光电学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）