PHYSICA SCRIPTA
·
2024
·Vol. 99
·期 8
·085914
·
IF 2.6
Yajun Xu,Qichen Zhao,Jianian Chen,Jingzhe Zhang,Binbin Xu
In recent years, graphene oxide assisted etching silicon has been considered a potential method to replace metal-assisted chemical etching. This work demonstrated the catalytic ability of graphene oxide synthesized by the Hummers method to promote chemical etching of silicon. By adjusting HF/H2O2 ratio of the solution and reaction temperature, a minimum weighted average reflectance of 9.9% in the wavelength range of 300–1100 nm was obtained. An etching rate of 10 μm h−1, faster than those in others' reports, was obtained in an optimized acidic solution at 80 °C. Finally, a four-electron model for graphene oxide assisted etching mechanism was proposed to explain our research results.
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
JOURNAL OF FLUORINE CHEMISTRY
·
2017
·
IF 2.101
Donghan Li,Mingyi Liao
This study evaluates the dehydrofluorination mechanism, structure and thermal stability of pure fluoroelastomer which was dissolved by organic solvent and reacted with different concentrations of KOH at 20 ∼ 60 °C. The sequence types and contents of double bonds and other oxygen-containing groups of samples were analyzed and investigated by Attenuated total reflectance/Fourier transform infrared (ATR-FTIR), 1 H nuclear magnetic resonance (NMR), 19 F-NMR spectroscopy and chemical titration method; thermal decomposition temperatures of samples were analyzed by thermogravimetric analysis (TGA). The results revealed that dehydrofluorination of fluoroelastomer would accompain with oxidation reaction whereby some double bonds conforming to Hofmann’s rule had been converted to hydroxyl groups, wherein the temperature and alkali concentration were the important factors. The double bonds generated in seven positions of molecular chains, sequence types were mainly conformed to Hofmann’s rule and Zaitsev’s rule supplemented. With the increase of reaction temperature and concentration of KOH, the thermal stability of fluoroelastomer decreased obviously since hydroxyl groups had a greater effect on it. Finally, the mechanism of reaction was also deduced.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Xinrui Huang,Jingsong Liu,Mengshi Zeng,Xiaowei Yang,Xiaojiang Liu
In this article, the MgO imporous fibers, MgO porous fibers and hydrofluoric acid (HF) modified MgO porous fibers were researched as the electrolyte binders in Li–Si/LiCl–KCl/FeS 2 thermal batteries respectively. The results show that the wettability between the LiCl–KCl molten salt and the MgO fiber binders increases significantly in order of MgO porous fibers and HF modified MgO porous fibers. The separator pellet using the MgO porous fiber modified by 40 mol% (of the MgO fiber) HF solution as the electrolyte binder exhibits an extremely small amount of electrolyte leakages (19.6 mg cm −2 ) and the highest ionic conductivity (0.66 S cm −1 at 450 °C). Meanwhile, the corresponding thermal battery shows the largest discharge capacity (425 mA h g −1 at 1.0 V voltage plateau). Moreover, the effect of HF modification on the ion migration was analyzed based on the analysis of element diffusion and the formed MgF 2 phase. In summary, modification of MgO porous fiber binder by HF solution is a potential way to improve the performance of thermal batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Yiwei Sun,Xiaoli Wei,Fangcao Liu,Bing Liu,Jiaming Zhao,Yubao Bi,Wenfeng Han
Developing effective techniques to produce and stabilize highly active metastable F-Al-O species in HFCs dehydrofluorination system without being over-fluorinated to Al-F is a major challenge. Herein, we report a new strategy for the formation and stabilization of metastable species. Using NaH 2 PO 4 as a P source, phosphoric acid groups are modified to the surface of Al 2 O 3 leading to the fabrication of AlPO 4 /Al 2 O 3 interface. P and Al 2 O 3 bond to form Al-O-P structure at the interface and stabilize F-Al-O in the dehydrofluorination system. Further studies show that AlPO 4 /Al 2 O 3 interface increase the oxygen vacancy content of catalyst and accelerate the conversion of HFC-152a on the catalyst surface. Meanwhile, AlPO 4 /Al 2 O 3 interface improves the surface acidity of Al 2 O 3 , endue a large number of Lewis weak acid sites, reducing the carbon accumulation of catalyst, and improving the stability of catalyst. The activity test showed that AlPO 4 /Al 2 O 3 interface shows high catalytic performance (74.2 %) and excellent stability (50 h) for 1,1-difluoroethane dehydrogenation compared with Al 2 O 3 (30 % and low stability) without P modification.
研究领域:
化学工程
·
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 52
·期 4
·2200-2209
·
IF 2.302
Liu Yong,Zhang Xuefeng,Dong Shangli,Ye Zhuyu,Wei Yidan
The highly exfoliated Ti 3 C 2 T
x
nanosheets were synthesized by selective etching of the starting material of Ti 3 AlC 2 using 40 % concentrated HF solution at 65 °C for 5 h. The effect of HF treatment temperature on the exfoliation degree was investigated by characterizing the morphology and microstructure of the Ti 3 C 2 T
x
nanosheets using SEM, XRD, and TEM. The results showed that the exfoliation degree of Ti 3 C 2 T
x
was increased with increasing temperature. The role of the termination groups produced during HF treatment on the exfoliation degree was discussed. The tribological property of the prepared Ti 3 C 2 T
x
nanosheets as additives in PAO8 base oil was measured. The maximum reduction of friction and wear was achieved under additive concentration of 0.8 wt% for the highly exfoliated Ti 3 C 2 T
x
nanosheets. The different effects of Ti 3 C 2 T
x
additives on the average friction coefficient and wear volume were analyzed, respectively.
研究领域:
材料科学
·
摩擦学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMIE INGENIEUR TECHNIK
·
2017
·Vol. 89
·期 10
·1333-1342
·
IF 0.877
Guanghua Ye,Zhongyuan Guo,Yuanyuan Sun,Kake Zhu,Honglai Liu,Xinggui Zhou,Marc-Olivier Coppens
The nature of external surface barriers in the zeolite ZSM-5 was explored by comparing mass transfer of n -heptane in samples with different crystal sizes, surface structure, and composition. These different surface properties were achieved by HF acid etching and SiO 2 deposition on an as-synthesized ZSM-5 crystal sample. HF etching does not reduce surface barriers. SiO 2 deposition on the same sample reduces surface barriers significantly. These insights into the nature of surface barriers could be used to guide the rational design of zeolitic materials with better mass transport properties.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2018
·Vol. 2
·期 7
·1481-1490
·
IF 0
Rong Zhou,Jianxing Huang,Shaobo Lai,Jiyang Li,Feng Wang,Zhiqiang Chen,Weiqing Lin,Chao Li,Jing Wang,Jinbao Zhao
A novel strategy for selecting an additive based on understanding the influence of different functional groups on electrochemical characteristics is adopted. N,N-Diethylamino trimethylsilane (DEATMS) is tested as a bifunctional electrolyte additive to scavenge H2O and neutralize HF in the electrolyte and enhance the behaviour of graphite/LiNi0.5Co0.2Mn0.3O2 cells operating at a high voltage (4.5 V vs. Li/Li+) or elevated temperature (55 °C). With 2% DEATMS, no LiPF6 hydrolysis species is found after storage at 55 °C for 6 days, even with a moisture content of 2000 ppm in the electrolyte. In addition, the graphite/LiNi0.5Co0.2Mn0.3O2 cells containing DEATMS show cycling performances superior to those of the cells without DEATMS upon cycling for 100 cycles at a high voltage (85.5% vs. 72.0%) or high temperature (81.2% vs. 70.6%). The sacrificial oxidation of DEATMS on the cathode surface restricts direct contact between the electrolyte and cathode, improving the electrochemical performance. The ex situ surface analysis of the electrodes after cycling indicates that both the electrolyte decomposition and Mn dissolution are inhibited by the deposition of DEATMS oxidation products.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Chunling Chen,Hui Long,Yangyang Luo,Kuantao Zhang,Chongyu Du,Hongyan Pan,Qian Lin,Zheng Chen
The purification of wet-process phosphoric acid has always posed a challenge for both academic and industrial researchers. In order to address this issue, a treatment unit was developed to mitigate magnesium and aluminum impurities from industrial semi-aqueous wet process phosphoric acid (SWPPA) (39.4 wt% P 2 O 5 ) through ralstonite precipitation using Na + /F − as the precipitator (F − provided by HF). Thermodynamic analysis, DFT calculation and separation experiments results were used to investigate the impact of sodium sources properties on impurities removal rates and H 3 PO 4 yield. Additionally, the effects of reaction temperature, reaction time, precipitating agent dosage, and aging time on precipitation efficiency were also examined. The results show that the ability of sodium source to ionize Na + and react with H 3 PO 4 and HF plays a crucial role in determining the impurity removal performance of magnesium and aluminum. The precipitants NaCl and Na 2 CO 3 exhibit the highest removal rates for magnesium and aluminum, which is attributed to the easy ionization of Na + ions. In comparison to Na 2 CO 3 , the higher H 3 PO 4 yield with NaCl as precipitator can be achieved due to its lower nucleation rate and higher crystal growth rate in the phosphoric acid system. NaCl and HF as precipitants effectively reduces the concentrations of magnesium and aluminum in the untreated SWPPA solution from 23.47 g MgO/kg P 2 O 5 to 3.29 g MgO/kg P 2 O 5 , 48.98 g Al 2 O 3 /kg P 2 O 5 to 15.54 g Al 2 O 3 /kg P 2 O 5 . The removal rates for magnesium and aluminum are found to be 85.98% and 68.27%, respectively, with minimal residue of Na + /F − .
研究领域:
化学工程
·
材料科学
✓ 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）