Polymers
·
2015
·Vol. 7
·期 10
·1939-1953
·
IF 3.681
Zhongkai Hu,Lei Zu,Yanhua Jiang,Huiqin Lian,Yang Liu,Zhenzi Li,Fei Chen,Xiaodong Wang,Xiuguo Cui
The PANI/Mesoporous MnO2composites were prepared through a simple one step method and we introduced the KI-H2SO4solution as the electrolyte of PANI/MnO2composites creatively. The characterization of structure, morphology, and composition are obtained by X-ray diffraction, Fourier transform infrared spectroscopy, thermal gravity analysis, Raman spectra, and scanning electron microscope. The electrochemical performances were investigated by constant-current charge–discharge, the voltammetry curve, and alternating current (AC) impedance technique. The specific capacitance of composites is 1405 F/g, which is almost 10 times larger than MnO2(158 F/g). We also find that the iodide concentration is closely related to the specific capacitance. Therefore, we explored the specific capacitance at different iodide concentration (0.05, 0.1, 0.2, 0.5, and 1 M), the results indicated that the specific capacitance reached a maximum value (1580 F/g) at 0.5 mol/L. Additionally, the PANI/Mesoporous MnO2composites not only exhibited a good ratio discharge property (857 F/g) at high current density, but also revealed an excellent cycling stability after 500 cycles, which retained 90% of the original specific capacitance.Keywords:polyaniline;mesoporous MnO2;specific capacitance;KI
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2024
·
IF 3.1
Shichun Weng,Juan Zhou,Yingtao Tian,Xigui Jiang,Rong Chen,Jinyao Hu,Zichao Guo,Liping Chen,Wanghua Chen
In this article, a mixture of sulfuric acid and 50% hydrogen peroxide solution was used to produce Caro’s acid, which serves as an oxidant frequently encountered in the fine chemical industry. The chemical compatibility between 50% H2O2/H2SO4 and organic solvents is an important safety issue. The compatibility of 50% H2O2/H2SO4 and several organic solvents, including ethanol, acetonitrile, ethyl acetate, DMF, dichloroethane, DMSO, ether, and toluene, was studied by reaction calorimetry and thermal analysis techniques. It was found that the first five solvents presented good compatibility with 50% H2O2/H2SO4. DSC tests indicated that these five solvents almost did not react with 50% H2O2/H2SO4 before the onset decomposition temperature of 50% H2O2/H2SO4 (∼93.3 °C). RADEX tests showed that the reactions of 50% H2O2/H2SO4 with these solvents released heats from 800 to 1100 J g–1, and the pressure effect was obvious for these mixtures. In contrast, the last three solvents, namely, DMSO, ether, and toluene, were incompatible with 50% H2O2/H2SO4, exhibiting a significant exothermic signal at lower temperatures. Most interestingly, the mixture of DMSO and 50% H2O2/H2SO4 presented a thermal runaway phenomenon below 40 °C. The causes of this thermal runaway incident were confirmed to be the oxidation of DMSO by Caro’s acid. Reaction calorimetry tests also indicated that the oxidation rate of DMSO was fast even at 40 °C, and the adiabatic temperature rise for the oxidation of DMSO was higher than 400 K.
研究领域:
化学工程
·
安全科学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2016
·Vol. 92
·期 4
·827-833
·
IF 2.738
Jinxi Feng,Shenyu Lan,Chunyang Yao,Ya Xiong,Shuanghong Tian
BACKGROUND Electro-generation of NaOH and H 2 SO 4 with organic compound-free Na 2 SO 4 wastewater has been known for many years, but actually, lots of Na 2 SO 4 wastewater contains organic pollutants, such as black liquor, dyeing and sulphonating wastewater etc., therefore, there is a strong demand for investigations on performance and effect of the organic pollutants in electrochemically splitting Na 2 SO 4 into H 2 SO 4 and NaOH from these wastewaters. RESULTS Co-electrolysis of Na 2 SO4 (1.13 mol L −1 ) and AO7 (50 ∼ 500 mg L −1 ) was investigated in a diaphragm cell with IrO 2 -coated Ti electrodes. It was found that the concentrations of the resulting NaOH and H 2 SO 4 could remain at about 0.73 mol L −1 and 0.36 mol L −1 , respectively, although the COD removal was increased from 50.3 mg L −1 to 166.3 mg L −1 with the increase of AO7 concentration, for 120 min. CONCLUSION In a diaphragm cell with IrO 2 -coated Ti electrodes, NaOH and H 2 SO 4 could be effectively generated, and simultaneously, AO7 could also be degraded for the wastewater containing Na 2 SO 4 and AO7. Interestingly, the electro-generation of NaOH and H 2 SO 4 was not significantly affected by the occurrence and degradation of AO7 in the range 0–500 mg L −1 . The phenomenon of constant acid–base yield contributed to the independence of the main acid-generating reactions on the electro-oxidation of AO7. © 2016 Society of Chemical Industry
研究领域:
环境科学
·
电化学工程
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DOI
高影响因子
GREEN CHEMISTRY
·
2014
·Vol. 17
·期 1
·335-342
·
IF 6.852
Muge Niu,Yucui Hou,Shuhang Ren,Wenhua Wang,Qitian Zheng,Weize Wu
Conversion of cellulose, the most abundant biomass, shows a high selectivity to yield formic acid (FA), when oxidized by O2 in NaVO3–H2SO4 aqueous solution. This conversion involves various reactions including hydrolysis and oxidation. In this work, the relationships between these reactions were studied. There are mainly two hydrolyses and two oxidations occurring in the conversion: initial hydrolysis (from cellulose to monosaccharides) and deep hydrolysis (from monosaccharides to levulinic acid); catalytic oxidation (from monosaccharides to FA) and ordinary oxidation (from levulinic acid to acetic acid). Among these four reactions, catalytic oxidation to FA and deep hydrolysis to byproducts are competitive. The increasing rate of deep hydrolysis is faster than that of catalytic oxidation, when temperature is increased. Catalytic oxidation is promoted and deep hydrolysis is suppressed, when the O2 pressure is increased. Moreover, deep hydrolysis is promoted and catalytic oxidation is suppressed, when H2SO4 concentration is increased. The hydrolysis–oxidation pathway of this conversion was proposed. Thus, the byproducts could be inhibited, and FA-oriented transformation could be realized.
研究领域:
生物化学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Mihong Cao,Lucheng Li,Wenfeng Yuan,Jun Chen
In order to solve the problems of insufficient adsorption electrolyte capacity and small specific surface area caused by the smooth surface and few pores of Super P spherical conductive particles, this work uses concentrated sulfuric acid (H 2 SO 4 ) for surface etching of Super P conductive particles to explore the influence of different etching time on the micromorphology of SP conductive agent and the behaviors of LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM-523) batteries. After etched by concentrated H 2 SO 4 , the surface of SP conductive agent changes from “capillary” structure to fluffy “plush” structure, effectively improving the conductivity specific surface area of the conductive agent particles. Compared with the pristne SP-0H conductive agent, the batteries using 1.5% of concentrated H 2 SO 4 etched SP-1H, SP-2H and SP-20H conductive agent have smaller EIS impedance value, larger area of CV curves, and smaller potential difference of the redox peaks. As a result, the initial charging/discharging capacities of SP-1H, SP-2H and SP-20H conductive batteries were 178.7/183.0, 187.6/183.9, 178.9/180.8 mAh/g with corresponding ICE of 102.4%, 98.0% and 101.1% respectively, which were much higher than the pristine SP-0H conductive battery (182.0/173.7 mAh/g with ICE of 95.4%). In addition, the SP-1H, SP-2H and SP-20H batteries also show significantly improved cycle performance and rate cycle capabilities, showing more superior comprehensive behaviors, which can provide a new modification insights for the exploration of new conductive agent in NCM-523 of high-performance lithium ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2017
·
IF 1.174
Yuedong Zhou,Fengfu Li,Junwei Liu,Zhi Yun,Xia Gui
The liquid phase ring-opening of octamethylcy-clotetrasiloxane (D 4 ) was investigated over Pt-H 2 SO 4 /Zr-montmorillonite catalyst. Montmorillonite (Mt), Zr-Mt, H 2 SO 4 /Mt, H 2 SO 4 /Zr-Mt and Pt-H 2 SO 4 /Zr-Mt were also detected for evaluation. The catalysts were characterized by X-ray fluorescence, X-ray diffraction, nitrogen adsorption–desorption, NH 3 -TPD and pyridine-FTIR measurements. In comparison to activate clay which is used in the industry of catalyst, Zr-Mt catalyst displayed stronger acidity and more excellent catalytic activity in the polymerization of D 4 , polymethylhydrosiloxane (D 4 H ) and hexamethyldisiloxane (MM) to low-hydro silicone oil. Relative to Zr-Mt, the acidity of H 2 SO 4 /Zr-Mt was noticeably improved and the catalyst exhibited a higher capability of ring-opening of D 4 conversion and yield of low-hydro silicone oil. To enhance the stability of H 2 SO 4 /Zr-Mt catalyst, a small amount of metals (Pt) was doped. The nitrogen adsorption–desorption results indicated that pore textural parameters of the Pt-H 2 SO 4 /Zr-Mt had not changed with larger specific surface area. Compared with H 2 SO 4 /Zr-Mt, the total acidity of Pt-H 2 SO 4 -Zr/Mt catalyst retained, but the content of the Brønsted acid increased and the content of the Lewis acid decreased. The Pt-H 2 SO 4 -Zr/Mt catalyst displayed higher catalyst reproducibility. After 40 h reaction of polymerization, the yield of low-hydro silicone oil decreased from 93% to 42% over H 2 SO 4 /Zr-Mt catalyst, while the yield of low-hydro silicone oil reduced from 93% to 78% over Pt-H 2 SO 4 /Zr-Mt catalyst. A sharp decrease in catalytic activity after 35 h of Pt-H 2 SO 4 /Zr-Mt catalyst was detected. Furthermore, Pt-H 2 SO 4 /Zr-Mt was completely regenerated under appropriate condition and appeared good repeatability in the D 4 , D 4 H and MM to low-hydro silicone oil.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 19
·7876-7883
·
IF 3.288
Cheng Zhang,Shijie Xiao,Zhigang Shen,Runping Li,Jianhua Liu,Shenghui Guo,Lei Xu
The effects of various KClO3 concentrations and durations on polyacrylonitrile (PAN) fibers were investigated. The oxidation treatment of PAN fibers (PFs) in a KClO3/H2SO4 system is a new pretreatment method for carbon fiber oxidation stabilization. Wettability (droplet shape), chemical structures (Fourier transform infrared spectroscopy [FT-IR]), crystal structures (wide-angle X-ray diffraction), microscopic structures (scanning electron microscopy), and chemical components (X-ray photoelectron spectroscopy) were analyzed. The PFs had the smallest contact angle and the best wettability when the KClO3 concentration was 15 wt%. FT-IR analysis showed that the absorption peak of the fibers was the lowest when the KClO3 concentration was 15 wt%. The peak intensities of MPFs-15-60 and MPFs-15-90 at 2θ = 17° and 2θ = 29°, respectively, were close and lower than the peak intensities of others. The number of grooves present on the fiber surface decreased when the KClO3 concentration was 15 wt%. As the KClO3 concentration increased, the elemental C content decreased and the elemental O content increased. MPFs-15-60 had a low C content and the highest O content, indicating that it had the highest degree of oxidation. The best sample for PF oxidation treatment with KClO3 was MPFs-15-60. The optimal processing conditions were a KClO3 concentration of 15 wt% and duration of 60 min.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2020
·
IF 3.421
Yangyang Xin,Yufeng Hu,Mengchen Li,Kebin Chi,Shang Zhang,Fei Gao,Siqi Jiang,Yichuan Wang,Chunxiao Ren,Guohua Li
Alkylation catalyzed by concentrated sulfuric acid (H2SO4) is an important process for industrial production of excellent high octane gasoline blending components. This process has some vital drawbacks such as extensive side reactions and high consumption of H2SO4 due to the presence of the most notorious impurities including H2O, acid soluble oil (ASO), and esters. In this study, isobutane alkylation was studied with H2SO4 (275 mL) in a batch reactor at −10 to 0 °C and 0.45 MPa, with the corresponding stirrer speed, feed rate, acid/hydrocarbon volume ratio, and isobutane/isobutylene volume ratio being 3000 rpm, 5.0 mL/min, 1.2, and 14.3, respectively. The effects of the acid strength and composition of acid on the alkylate quality were investigated. The composition of used acid was analyzed. The results show that used acid is mainly composed of roughly 89% free H2SO4, 6% H2O, 2% esters, and 3% ASO. The compounds existing in the ASO extracted from used acid were identified, and their concentrations were quantitatively determined. The results show that the most abundant ASO molecules are five-membered or six-membered cyclic homoannular conjugated olefins such as cyclopentadiene (15.67%) and cyclohexadiene (14.12%). The effects of acid strength, H2O, ASO, and esters on alkylation depend strongly on the concentrations of H2SO4 and these impurities. Therefore, their optimal concentrations were determined to achieve advantageous effects on the alkylation. The results are about 93–95% for H2SO4, 2–4% for H2O, 1.5–2.5% for ASO, and 0.4–1% for esters, beyond which an adverse effect will appear. Under the optimal concentrations, the value of the research octane number, the trimethylpentane (TMP)/dimethylhexane ratio, and the contents of C8 and TMP remained steady at high levels of about 92–93, 5.8–6.3, 68–70, and 58–60%, respectively.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
Chemosensors
·
2020
·Vol. 8
·期 4
·109
·
IF 3.108
Yuhang Zhang,Dongliang Cheng,Zicheng Wu,Feihu Li,Fang Fang,Zili Zhan
The conventional CO electrochemical gas sensor uses aqueous H2SO4solution as electrolyte, with inevitable problems, such as the drying and leakage of electrolyte. Thus, research on new alternative electrolytes is an attractive field in electrochemical gas sensors. In this paper, the application of a new fumed SiO2gel electrolyte was studied in electrochemical gas sensors. The effects of fumed SiO2and H2SO4contents on the performance of the CO gas sensor were investigated. The results showed that the optimized composition of the SiO2gel electrolyte was 4.8% SiO2, 38% H2SO4, and 0.005% polyvinyl alcohol (PVA). Compared with aqueous H2SO4, the gel electrolyte had better water retention ability. The signal current of the sensor was proportional to the CO concentration. The sensitivity to CO was 78.6 nA/ppm, and the response and recovery times were 31 and 38 s, respectively. The detection limit was 2 ppm. The linear range was from 2 to 500 ppm. The gel electrolyte CO sensor possesses equivalent performance to that with aqueous electrolyte.Keywords:fumed SiO2;gel electrolyte;electrochemical sensor;CO gas sensor
研究领域:
材料科学
·
传感器技术
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2017
·
IF 3.752
Muge Niu,Yucui Hou,Weize Wu,Ru Yang
Catalytic oxidation of lignocellulose in hydrothermal condition catalyzed by vanadium-containing homogeneous catalysts is a promising method to prepare formic acid (FA), a potential material in emerging field of clean energy technologies . The FA production from polysaccharides components of lignocellulose has already been well studied. However, the conversion of lignin component, which quite differs in structure from polysaccharides, has not been studied systematically. In this work, the lignin degradation was studied in NaVO 3 -H 2 SO 4 aqueous solution with O 2 as oxidant. The degradation mechanism was studied in detail. Compared with polysaccharides, lignin can produce a much lower yield of FA with a formation of a larger amount of CO 2 . H 2 SO 4 can catalyze highly-polymerized lignin to segments by C O bond hydrolytic cleavage, but the conversion is limited. NaVO 3 and O 2 can accelerate the lignin degradation by weakening the C O bond. In liquid phase, NaVO 3 and O 2 , with a low selectivity on products, lead to different kinds of reactions, mainly including phenolic hydroxyl oxidation to quinone , aliphatic hydroxyl oxidation to ketone/aldehyde, aliphatic C C bond cleavage , intramolecular dehydration and decarboxylation . This study gives a deep understanding of lignin transformation during catalytic oxidation, and provides guidance to the further application of FA production from natural lignocellulose.
研究领域:
生物质化学
·
可再生能源技术
✓ 已验证
产品关联
DOI
高影响因子
CORROSION SCIENCE
·
2022
·
IF 7.72
Kaixin Xu,Wen Sun,Lida Wang,Zhengqing Yang,Bohang Li,Yunsheng Ma,Liqiu Zhao,Chenghe Zhang,Shiheng Ma,Haoxue Han,Guichang Liu
To improve the corrosion protection properties of polytetrafluoroethylene (PTFE) in highly corrosive H 2 SO 4 solutions, Janus PTFE coatings (PDA/PEI@PTFE) were constructed. The modified side is achieved by co-deposition of polydopamine (PDA) and polyethyleneimine (PEI) on the sodium naphthalene etched side of PTFE. It not only has a 5-fold increase in interfacial adhesion with substrates via chemical bonds, but also exhibits improved barrier properties due to the coverage of dense PDA/PEI film, with corresponding corrosion resistance increase by ~2–3 orders of magnitude. Meanwhile, the untreated side is hydrophobic pristine PTFE and has good self-cleaning properties and excellent resistance in concentrated H 2 SO 4 solutions.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2016
·Vol. 18
·期 12
·1-9
·
IF 2.101
Song Haijun,Cai Kefeng,Shen Shirley
Firstly, tellurium (Te) nanorods with a high Seebeck coefficient have been integrated into a conducting polymer PEDOT/PSS to form PEDOT/PSS/Te composite films. The Seebeck coefficient of the PEDOT/PSS/Te (90 wt.%) composite films is ~191 μV/K, which is about 13 times greater than that of pristine PEDOT/PSS. Then, H 2 SO 4 treatment has been used to further tune the thermoelectric properties of the composite films by adjusting the doping level and increasing the carrier concentration. After the acid treatment, the electrical conductivity of the composite films has increased from 0.22 to 1613 S/cm due to the removal of insulating PSS and the structural rearrangement of PEDOT. An optimized power factor of 42.1 μW/mK 2 has been obtained at room temperature for a PEDOT/PSS/Te (80 wt.%) sample, which is about ten times larger than that of the untreated PEDOT/PSS/Te composite film.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）