scholarly journals A Polypyrrole-Modified Pd-Ag Bimetallic Electrode for the Electrocatalytic Reduction of 4-Chlorophenol

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 931
Author(s):  
Xuefeng Wei ◽  
Laiyuan Zeng ◽  
Weiwei Lu ◽  
Juan Miao ◽  
Ruichang Zhang ◽  
...  

A polypyrrole-modified bimetallic electrode composed of Pd-Ag on a Ti substrate (Pd-Ag/PPY/Ti) was successfully prepared via a chemical deposition method, and was applied to the electrocatalytic hydrodechlorination of 4-chlorophenol (4-CP) in aqueous solution. The electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Various influences on the dechlorination efficiency of 4-chlorophenol, including applied current, initial pH value, and temperature, were studied. The dechlorination efficiency of 4-CP reached 94% within 120 min under the optimum conditions, i.e., a dechlorination current of 6 mA, an initial pH of 2.30, and a temperature of 303 K. The apparent activation energy of the dechlorination of 4-CP by the Pd-Ag/PPY/Ti electrode was calculated to be 49.6 kJ/mol. The equivalent conversion rate constant kPd was 0.63 L.gPd−1·min−1, which was higher than the findings presented in comparable literature. Thus, a highly effective bimetallic electrode with promising application prospects and low Pd loading was fabricated.

2011 ◽  
Vol 399-401 ◽  
pp. 1030-1033
Author(s):  
Zi Xian Xu ◽  
Feng Zhu Lv ◽  
Xue Feng ◽  
Yi He Zhang

As additive, economic and low resistivity material was useful in the fields of electrostatic prevention and electromagnetism screening. Antimony-doped tin oxide(Sb:SnO2)/talc composite was prepared for this purpose via a modified chemical deposition method using economic and natural talc as matrix. Effects of hydrolysis temperature, pH value, doping concentration of antimony, proportion of Sb:SnO2 to talc, calcination temperature and time on the resistivity of the composite powder were investigated. The construction of Sb:SnO2/talc conductive composite was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The resistivity of Sb:SnO2/talc composite prepared at the optimum conditions decreased to 3.0×103 Ω•cm, at the same time its whiteness was greatly improved.


2021 ◽  
Author(s):  
Rong Chen ◽  
Dan Zhao ◽  
Yanmao Dong ◽  
Chengrun Cai ◽  
Yan Yuan ◽  
...  

Abstract manganese doped iron oxychloride (Mn-FeOCl) was synthesized by partial pyrolysis method. The Mn-FeOCl was used as heterogeneous catalyst to activate permonosulfate (PMS) for the degradation of azo dye acid red B(ARB) for the first time. The Mn-FeOCl was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). The effects of Mn-FeOCl dosage, PMS concentration, initial pH value, Cl ion concentration and humic acid (HA) dosage on the degradation of ARB by Mn-FeOCl/PMS were investigated. Results showed that the ARB was degraded effectively by Mn-FeOCl/PMS. The mineralization rate of ARB reached 42.5%. As the Mn-FeOCl dosage was 0.1g/L, PMS concentration was 1mmol/L, and ARB concentration was 0.05mmol/L, the degradation rate of ARB reached 99.4% in 30 minutes. With the increase of PMS dosage, Mn-FeOCl dosage, Cl− ion concentration and initial pH value, the decolorization effect of ARB increased. The reaction mechanism was analyzed by free radical quenching experiment and XPS. The main active species were determined as ·OH and SO4·− which generated by PMS activation. The SO4·−−was the main active species.


2017 ◽  
Vol 76 (6) ◽  
pp. 1436-1446 ◽  
Author(s):  
Chenmo Wei ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
Peng Zhou ◽  
...  

Sulfate radical-based advanced oxidation processes have had considerable attention due to the highly oxidizing function of sulfate radicals (SO4−·) resulting in acceleration of organic pollutants degradation in aqueous environments. A Co-Ni mixed oxide nanocatalyst, which was prepared by the sol-gel method, was employed to activate peroxymonosulfate (PMS, HSO5−) to produce SO4−· with Acid Orange 7 (AO7) selected as a radical probe. The catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The characterization results indicated that the ingredient of the catalyst had been changed and the amount of surface hydroxyl increased significantly with the addition of Ni. Therefore, it proved that Co-NiOx catalyst was more effective than CoOx to activate PMS. Moreover, ultrasound (US) can increase the degradation rate of AO7 and US/Co-NiOx/PMS system. This study also focused on some synthesis parameters and the system reached the maximum efficiency under the condition when [PMS] = 0.4 mM, [catalyst] = 0.28 g/L, Pus = 200 W. The AO7 removal in these systems follows first order kinetics. Last but not least, quenching studies was conducted which indicated that the amount of hydroxyl radicals (·OH) increases with the increase of initial pH and SO4−· was the primary reactive oxidant for AO7 degradation.


2019 ◽  
Vol 79 (12) ◽  
pp. 2357-2365 ◽  
Author(s):  
Huaisu Guo ◽  
Weilin Guo ◽  
Yang Liu ◽  
Xiaohua Ren

Abstract In this work, quinone-modified metal-organic framework MIL-101(Fe)(Q-MIL-101(Fe)), as a novel heterogeneous Fenton-like catalyst, was synthesized for the activation of persulfate (PS) to remove bisphenol A (BPA). The synthetic Q-MIL-101(Fe) was characterized via X-ray diffraction, scanning electron microscope, Fourier transform infrared, electrochemical impedance spectroscopy, cyclic voltammetry and X-ray photoelectron spectroscopy. As compared to the pure MIL-101(Fe), Q-MIL-101(Fe) displayed better catalytic activity and reusability. The results manifested that the Q-MIL-101(Fe) kept quinone units, which successfully promoted the redox cycling of Fe3+/Fe2+ and enhanced the removal efficiency. In addition, the reaction factors of Q-MIL-101(Fe) were studied (e.g. pH, catalyst dosage, PS concentration and temperature), showing that the optimum conditions were [catalyst] = 0.2 g/L, [BPA] = 60 mg/L, [PS] = 4 mmol/L, pH = 6.79, temperature = 25 °C. On the basis of these findings, the probable mechanism on the heterogeneous activation of PS by Q-MIL-101(Fe) was proposed.


2011 ◽  
Vol 391-392 ◽  
pp. 1132-1137
Author(s):  
Su Ping Huang ◽  
Jun Zhu ◽  
Ke Chao Zhou

Luminescence behaviors and morphology of Eu3+doped hydroxyapatite synthesized under different pH values were well investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Inductively Coupled Plasma (ICP) (ICP–PLASMA 1000), and photoluminescence (PL) spectroscopy. Results revealed that With pH values increased from 6.5 to 10.0, the morphology of nano-Eu:HA particles changes from rod particles to equiaxed particles. The actual doping concentration and aspect ratio of Eu3+-doped HA decreased with the increasing of pH value. At the same time, the fluorescence intensity also tends to weakly lower with the increasing of pH value, which indicated that the luminescence properties mainly depended on the actual Eu3+doping concentration, the influences of morphology on the luminescence properties were slight.


2013 ◽  
Vol 652-654 ◽  
pp. 1580-1584
Author(s):  
Yu Jiang Guan ◽  
Zi Bo Wang ◽  
Shu Li Bai ◽  
Qin Xue

N-doped Titanium dioxide (TiO2) nanotube arrays were characterized by scanning electron microscope (SEM),X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to analyse its surface morphology, crystal types and the doping behavior of nitrogen. The material was used as electrode for photoelectrocatalytic degradation of hexachlorobenzen under irradiation of simulated sunlight. The effects of photocatalysis, electrocatalysis, photoelectrocatalysis, the concentration of Na2SO4 and pH value on degradation of HCB were investigated.


2012 ◽  
Vol 465 ◽  
pp. 276-282
Author(s):  
Zhong Hui Gao ◽  
Zhen Duo Cui ◽  
Xian Jin Yang

Pt nanoparticles were successfully assembled in self-organized TiO2 nanotubes by a chemical deposition method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used for characterizing the surface morphology and phase composition. Photocurrent response activity was measured. Different morphology of Pt-TiO2 NTs exhibited different photocurrent generation efficiency. High density Pt nanoparticles depositing on TiO2 NTs decreased the photocurrent of Pt-TiO2 electrodes. It was because the high density Pt nanoparticles could become the recombination centers of photoelectrons and holes.


2018 ◽  
Vol 71 (11) ◽  
pp. 874 ◽  
Author(s):  
Xue Huang ◽  
Jing Zhang ◽  
Xiao Zhang ◽  
Qing-Ping Wu ◽  
Chun-Hui Yan

Calcined Cu-based metal–organic frameworks impregnated with nickel nitrate catalysts (CuNi@C) were synthesised. X-Ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy techniques were applied for the characterisation of the synthesised catalyst, which revealed an octahedral particle shape, rough surface, and metallic copper (Cu, CuO) and nickel (Ni, NiO) particles. CuNi@C was fabricated as a novel peroxymonosulfate (PMS) activator for the oxidative degradation of Acid Orange 7 (AO7) in aqueous media. Results showed that the CuNi@C/PMS system can efficiently degrade nearly 100 % of 0.02 mmol L−1 AO7 within 60 min. In addition, the trapping experiments confirmed the participation of sulfate radicals (SO4•−) and hydroxyl radicals (HO•) as reactive species in the system. Furthermore, the effects of parameters including catalyst and PMS dosages, initial concentration of AO7, and pH were studied. Results showed that the decolourisation efficiency increased with the increase of catalyst dosage, but decreased with the increase of AO7 concentration. The optimal PMS concentration was 0.675 mmol L−1, and initial pH showed no significant effect on the degradation of AO7. Moreover, the CuNi@C could be reused four times with good activity and reusability. Findings revealed that the CuNi@C/PMS system shows potential for degrading contaminants in the environment, due to its catalytic activity and non-negligible adsorption.


2018 ◽  
Vol 26 (1(127)) ◽  
pp. 25-29 ◽  
Author(s):  
Iwona Frydrych ◽  
Xie Juan

The immobilization of CuS on the surface of poly (ethylene terephtalate) (PET) fibres was carried out by the functionalization of PET fibres with chitosan (CS), followed by the chemical deposition method. Crosslinked chitosan with NH2 functionality was used as a chelator to absorb copper ions, which can successfully initiate CuS deposition in the following chemical deposition stage. The CuS-loaded fibres were characterised by scanning electron microscopy, X-ray diffraction, infrared spectroscopy and thermal gravimetry, respectively. The properties of tensile and conductivity were also investigated. The lowest surface resistance 42 Ω/cm of the treated PET fibres was obtained when the CS concentration was 1.0%.


Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 378 ◽  
Author(s):  
Junjing Li ◽  
Huan Wang ◽  
Liang Wang ◽  
Chang Ma ◽  
Cong Luan ◽  
...  

Noble metal palladium modified foamed nickel electrode (Pd/foam-Ni) was prepared by electrodeposition method. The fabricated electrode showed better catalytic performance than the Pd/foam-Ni prepared by conventional electroless deposition. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Electrocatalytic activity of the Pd/Ni was studied for the hydrodechlorination of monochlorophenol isomers. The Pd/Ni exhibited good catalytic activity for 3-chlorophenol (3-CP). Complete decomposition of chlorophenol isomers could be achieved within 2 h, and the hydrodechlorination process conformed to the pseudo-first-order kinetic model. It showed a supreme stability after recycling for 5 times. The Pd/Ni exhibited a promising application prospect with high effectiveness and low Pd loading.


Sign in / Sign up

Export Citation Format

Share Document