RSC Advances
·
2016
·Vol. 6
·期 60
·55618-55625
·
IF 3.289
Kun Li,Hua Zheng,Hong Zhang,Wen-wen Zhang,Kai Li,Juan Xu
This study made use of a novel totally chlorine-free (TCF) bleaching approach to prepare bleached shellac. Some single factor experiments were employed to investigate the effects of the main factors in the H2O2 bleaching method. A new chlorine-free bleached shellac resin was obtained in the Box–Behnken design responsive surface optimal experimental conditions (pH, 9.0–11.0; 1.33 mL g−1, concentration of 30% hydrogen peroxide; 2.0 h, dropping time of hydrogen peroxide; 7.2 h, bleaching time; 90 °C, temperature). The yield and color index of the bleached shellac obtained under the optimal experimental conditions were 80.84% and 0.5675 respectively. The result of the physicochemical property test, IR spectrum and DSC characterization indicate that the properties of H2O2 bleached shellac are similar to commercially refined shellac resin. Moreover, it is noteworthy that the H2O2 bleached shellac was remarkable in alcohol solubility and thermal lifetime tests. It had a higher acid value and a lower softening point compared with commercially refined shellac resin, which can be applied safely in many fields including food and medical industries without chlorine residues.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Qingrong Long,Chaoyang Shi,Dawei Zhang,Danyang Wei,Haoqi Li,Linxiang Zhou,Hanyu Tan,Jie Yu,Mingli Xu
The frequently used chloroplatinic acid or other Pt precursors containing Cl element during the preparation process of Pt-based catalysts lead to catalyst poisoning and instability. In this work, a chlorine-free PtCu(N)/C R-F catalyst with a hollow sphere structure was successfully synthesized by employing [Pt(NH 3 ) 4 ](OH) 2 and [Cu(NH 3 ) 4 ](OH) 2 as the chlorine-free metal precursors, which using the strong electrostatic adsorption (SEA) between positively charged metal precursor ions and the negatively charged oxygen-containing functional groups (OCFGs) on the carbon support (C R-F ) and combined with the impregnation reduction method. Compared to commercial Pt/C, the experimental results show that the PtCu(N)/C R-F catalyst, displays better ORR performance under acidic condition, the onset and half-wave potentials are 0.961 V (vs. RHE) and 0.827 V (vs. RHE), respectively. Furthermore, it also shows a significant performance advantage in a gas diffusion electrode (GDE) half-cell. Density-functional theory (DFT) calculations show that the introduction of Cu has adjusted the electronic structure of Pt, weakened the adsorption of oxygen-containing intermediates, and ultimately enhanced the catalytic activity and stability of ORR. This work presents a simple and efficient method for preparing chlorine-free Pt-based catalysts.
研究领域:
材料科学
·
催化化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Shuaiqi Wang,Yuangang Xu,Shuaijie Jiang,Feng Yang,Dongxue Li,Pengcheng Wang,Qiuhan Lin,Ming Lu
Finding a chlorine-free, environmentally friendly, high-energy dense oxidizer with a high heat of formation as an alternative to ammonium perchlorate (AP) has remained an extremely challenging task in the field of energetic materials. In the present work, two organic oxidizers, 4,4′-bis(trinitromethyl)-3,3′-azofurazan ( 8 ) and 4,4′-bis(trinitromethyl)-3,3′-azoxyfurazan ( 10 ), were designed and synthesized via a two-step reaction from 3-amino-4-(carboxymethyl)furazan. Their structural features were investigated by single-crystal X-ray diffraction, scanning electron microscopy, nuclear magnetic resonance, infrared spectroscopy, elemental analysis, and several theoretical techniques. Both of the newly synthesized organic oxidizers ( 8 and 10 ) exhibit positive oxygen balances, high densities, poor solubility in water, decent thermal stabilities, acceptable mechanical sensitivities, extremely high heats of formation, and excellent detonation performances. The best specific impulses are obtained for the environmentally friendly oxidizers 8 and 10 with calculated values of 273.9 s and 275.9 s, respectively, in a composite propellant consisting of 77 % oxidizer, 9 % aluminium, and 14 % binder. Both of these exceed the specific impulse (263 s) of the currently widely used oxidizer AP in the similar composition. Oxidizers 8 and 10 are expected to have promising applications as high-energy dense oxidizers for various scientific, space, and military projects.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2019
·
IF 1.911
Fanglu Yuan,Lele Cui,Peipei Ding,Wenheng Jing
Electrochemical technologies for the on-site treatment of spent acid etchant have received great attention due their ease of operation and economic benefits. On the other hand, a large amount of Cl 2 is generated during the electrolysis process, which leads to potential environmental risks. In the present work, a novel three-compartment ceramic membrane flow reactor, including a cathode chamber, an anode chamber, and a gas absorption chamber was developed. The three chambers were divided by an Al 2 O 3 ceramic membrane and a breathable hydrophobic anode diffusion electrode (ADE). The Cl 2 evolution onset potential of the ADE was increased to 1.19 V from 1.05 V of the graphite felt, effectively inhibiting the chlorine evolution reaction (CER). The anode-generated Cl 2 diffused into the gas absorption chamber through the ADE and was eventually consumed by the H 2 O 2 adsorbent. Cu could be recovered without emitting chlorine due to the special structure of reactor. The current efficiency of copper precipitation and cathode reduction from Cu 2+ to Cu + reached 97.7% at a working current of 150 mA. These results indicated that the novel membrane reactor had high potential for application in the copper recovery industry.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Wen Ren,Di Wu,Yanna NuLi,Xuan Zhang,Jun Yang,Jiulin Wang
The electrolyte based on magnesium bis(diisopropyl)amide (MBA), a low-cost and non-nucleophilic organic magnesium salt, is proposed to be an admirable alternative for rechargeable magnesium batteries but suffers from limited ionic conductivity and an inferior electrochemical window in the commonly used ether solvents. In this work, the 1-butyl-1-methylpiperidinium bis(trifluoromethyl sulfonyl)imide (PP14TFSI) ionic liquid as the cosolvent of tetrahydrofuran (THF) in chlorine-free MBA-based electrolytes has been first demonstrated to remarkably improve the ionic conductivity and broaden the oxidative stable potential (2.2 V vs Mg/Mg2+) on stainless steel. Reversible Mg electrochemical plating/stripping with a low overpotential below 200 mV and ca. 90% Coulombic efficiency are obtained. The current density of Mg plating/stripping is increased 238 times after the addition of PP14TFSI, where the mechanism of competitive coordination of TFSI– making an easier Mg plating/stripping is proposed theoretically. The MBA-2AlF3 electrolyte with a ratio-optimized THF/PP14TFSI cosolvent exhibits good compatibility with the Mo6S8 cathode. Furthermore, the Se@pPAN|Mg full cell exhibits an initial capacity of 447.8 mAh g–1 and as low as ∼0.66% capacity decay per cycle for more than 70 cycles at 0.2 C with the synergy of LiTFSI additives. The facile modification strategy of ionic liquid in the MBA-based electrolyte sheds inspiring light on exploring non-nucleophilic and chlorine-free electrolytes for practical rechargeable magnesium batteries.
研究领域:
材料科学
·
电化学
·
储能技术
·
电池技术
·
无机化学
·
物理化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）