Solid high-proton conductor tungstovanadozincic acid with transition metal as central atom: Synthesis and conductivity

2015 ◽  
Vol 08 (04) ◽  
pp. 1550041 ◽  
Author(s):  
Tianpei Huang ◽  
Xuefei Wu ◽  
Qingyin Wu ◽  
Fahe Cao ◽  
Wenfu Yan

A Keggin-type vanadium-substituted tungstovanadozincic heteropoly acid H 7 ZnW 11 VO 40 ⋅ 8 H 2 O , with the transition metal as central atom, was firstly synthesized and characterized. Its proton conductivity was measured by the electrochemical impedance spectrum (EIS), and the result indicates that the H 7 ZnW 11 VO 40 ⋅ 8 H 2 O is a solid high-proton conductor with conductivity of 3.26 × 10-3S ⋅ cm-1 at 58°C, 50% relative humidity. Its activation energy is 29.50 kJ ⋅ mol-1, which suggests that the mechanism of proton conduction is the Vehicle mechanism.

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Zhihong Zhang ◽  
Baoying Wang ◽  
Yijing Zhang ◽  
Gehong Zhang ◽  
Yujing Wang

A novel heteropoly acid salt, Na6[Ni(Mo11ZrO39)]·20H2O, has been synthesized by the means of acidification and adding the reactants into the solution step by step. The heteropoly compound was characterized by elemental analysis, TGA/DSC, infrared spectrum, ultraviolet spectrum, X-ray diffraction, and SEM. Its protonic conduction was measured by the means of the electrochemical impedance spectrum. The results showed that it belongs to the Keggin type, and its conductivity value was 1.23 × 10–2 S/cm at 23°C when the relative humidity was 60%, and the conductivity enhanced with the elevated temperature. Its proton conduction mechanism was in accordance with vehicle mechanism, and the activation energy was 27.82 kJ/mol.


2012 ◽  
Vol 05 (04) ◽  
pp. 1250040 ◽  
Author(s):  
XIA TONG ◽  
WEN WU ◽  
SHENGMING ZHOU ◽  
QINGYIN WU ◽  
FAHE CAO ◽  
...  

Highly proton-conducting hybrid materials ( P2W17V /PEG and P2W17V/PEG/SiO2 ) were prepared by heptadecatungstovanadodiphosphoric heteropoly acid with Dawson structure ( P2W17V , 90 wt.%), polyethylene glycol (PEG, 10 wt.% and 5 wt.%) and silica gel ( SiO2 , 0 wt.% and 5 wt.%). The products were characterized by the infrared (IR) spectrum, X-ray powder diffraction (XRD) analysis and electrochemical impedance spectrum (EIS). The result reveals that their conductivity values are 1.02 × 10-2 and 2.58 × 10-2S ⋅ cm-1 at room temperature (26°C) and 75% relative humidity (RH), respectively. Their conductivities increase with higher temperature and these activation energies of proton conduction are 9.51 and 14.95 kJ⋅mol-1, which are lower than that of pure heteropoly acid (32.23 kJ⋅mol-1). These mechanisms of proton conduction for these two materials are Grotthuss mechanism.


2021 ◽  
pp. 2150019
Author(s):  
Xuefei Wu ◽  
Qingyin Wu

A heteropoly acid (HPA) with Dawson structure, H6P2W[Formula: see text]Mo2O[Formula: see text]⋅29H2O, is synthesized with characterization and the investigation toward its proton conductive behavior. Actually, at 18[Formula: see text]C with 80% relative humidity (RH), H6P2W[Formula: see text]Mo2O[Formula: see text] ⋅ 29H2O displays the conductivity as 2.30 × 10[Formula: see text] S ⋅ cm[Formula: see text], indicating an excellent protonic conductor. The proton conduction activation energy is 32.19 kJ ⋅ mol[Formula: see text], implying proton migration following vehicle mechanism. During the measured range, higher temperature can boost the conductivity.


2016 ◽  
Vol 09 (03) ◽  
pp. 1650048 ◽  
Author(s):  
Huaxue Cai ◽  
Tianpei Huang ◽  
Qingyin Wu ◽  
Wenfu Yan

A ternary heteropoly acid (HPA) H6SiW[Formula: see text]V2O[Formula: see text]14H2O was prepared and investigated in this paper. The structure feature and hydration of this HPA was characterized by IR, XRD, UV, and TG-DTA. This HPA exhibits a high proton conductivity, which is [Formula: see text]S[Formula: see text]cm[Formula: see text] at 25[Formula: see text]C and 70% relative humidity. It is a novel high proton conductor. The conductivity increases with higher temperature, and it exhibits Arrhenius behavior, with the activation energy value of 21.02[Formula: see text]kJ[Formula: see text] mol[Formula: see text] for proton conduction, indicating the proton conduction mechanism is dominated by vehicle mechanism.


NANO ◽  
2020 ◽  
Vol 15 (07) ◽  
pp. 2050089
Author(s):  
Litong Niu ◽  
Shaoping Hu ◽  
Yali Ma ◽  
Mingming Wang ◽  
Bolin Lv ◽  
...  

Novel ZnIn2S4/FeUiO-66 (ZFeU) photocatalyst with different proportion of FeUiO-66 has been successfully prepared by a facile one-pot solvothermal reaction. The as-synthesized nanocomposites have been thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Brunauer–Emmett–Teller (BET) characterization, photoluminescence (PL) analysis and electrochemical impedance spectrum (EIS). The photocatalytic performance of ZFeU nanocomposites for the photodegradation of RhB under visible light irradiation was better than that of ZnIn2S4 and FeUiO-66 alone. The experiment results showed the 20% ZFeU nanocomposites had the best photocatalytic properties. At the same time, a probable mechanism was discussed and it was believed that introduction of FeUiO-66 on ZnIn2S4 would minimize the recombination of photogenerated electron-hole pairs, leading to the enhancement of the photocatalytic activity.


2011 ◽  
Vol 335-336 ◽  
pp. 779-782
Author(s):  
Shi Quan He ◽  
Hui Zhong

Corrosion behaviour of hot-dip galvanized steel in 5% NaCl aqueous solution was studied by electrochemical impedance spectrum (EIS) technique. The results revealed that corrosion behaviour of hot-dip galvanized steel has a great relationship with immersion time. With the increase of immersion time, corrosion products are constantly changing, and the impedance of corrosion products are different. Parameters fitted by equivalent circuit show that the impedance of corrosion products increased at first, then decreased.


2017 ◽  
Vol 60 (5) ◽  
pp. 1439-1443 ◽  
Author(s):  
Guohua Hui ◽  
Yibin Ying

Abstract. A quantitative rapid analysis method for ofloxacin detection in raw milk using molecule-specific recognition and an electrochemical impedance spectrum (EIS) technique was investigated in this study. An association complex (AC) formed by a combination of ofloxacin and sodium tetraphenylboron (ST) was used as the active material for electrochemical analysis. A carbon screen-printed electrode (CSE) was modified with the AC to form an electrochemical active membrane for ofloxacin detection. EIS data of pretreated raw milk samples were measured and analyzed with a non-linear bistable stochastic resonance (SR) model. Trace ofloxacin concentrations were characterized by SR output signal-to-noise ratio (SNR) eigen values. An ofloxacin quantitative analysis model was built based on SNR eigen values. Experimental results demonstrated that the proposed method presented good accuracy, repeatability, and recovery. It is a promising way for ofloxacin detection in raw milk. Keywords: Association complex, Electrochemical impedance spectrum, Ofloxacin, Quantitative analysis, Sodium tetraphenylboron.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sheng-xue Yu ◽  
Rui-jun Zhang ◽  
Yong-fu Tang ◽  
Yan-ling Ma ◽  
Wen-chao Du

Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF60.75 g·L−1, NaF 1.25 g·L−1, MgSO41.0 g/L, and tetra-n-butyl titanate (TBT) 0.08 g·L−1. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectrum (FT-IR) were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS). Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.


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