A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potenti...A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.展开更多
提出一种新型氧化还原液流电池:H2-Fe3+/Fe2+氧化还原液流电池。系统研究了Fe3+/Fe2+电对于未处理与热处理聚丙烯腈基石墨毡上的电化学性能及两种石墨毡组装电池充放电性能。实验结果表明:经热处理之后,石墨毡电化学反应活性面积变大,Fe...提出一种新型氧化还原液流电池:H2-Fe3+/Fe2+氧化还原液流电池。系统研究了Fe3+/Fe2+电对于未处理与热处理聚丙烯腈基石墨毡上的电化学性能及两种石墨毡组装电池充放电性能。实验结果表明:经热处理之后,石墨毡电化学反应活性面积变大,Fe3+/Fe2+电荷传递阻抗降低,从而降低了电池极化。以热处理石墨毡为电池正极,碳纸为负极组成电池,在50 m A/cm2充放电时,电压效率为87.43%,与用未处理石墨毡组装电池相比,电压效率提高11.82%,内阻降低50%。展开更多
This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical l...This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.展开更多
Electrode material is one of the most important factors affecting the performance of supercapacitors, and electrolyte solution is another. In this work, electrochemical properties of hydroxide zinc carbonate composite...Electrode material is one of the most important factors affecting the performance of supercapacitors, and electrolyte solution is another. In this work, electrochemical properties of hydroxide zinc carbonate composite electrode (HZC) in KOH + K3[Fe(CN)6] electrolyte were studied. It was proved that [Fe(CN)6]3−in electrolyte participated in electrochemical reactions and promoted electron transfer. The specific capacitance of HZC electrode was as high as 920.5 F·g−1 at 1.0 A·g−1 in 1 mol·L−1 KOH and 0.04 mol·L−1 K3[Fe(CN)6] electrolyte, which is 172.9% higher than that in KOH. The combination of HZC electrode and low alkalinity aqueous electrolyte provided the supercapacitor system with good capacitance performance, safety, and environmentally friendly.展开更多
In the presence of CrCl3/Fe redox system, polyfluoropolyhaloethanes readily added to electron-deficient or electron-rich alkenes, giving the corresponding 1:1 hydropolyfluoroalkylation product or 1:1 adduct in high yi...In the presence of CrCl3/Fe redox system, polyfluoropolyhaloethanes readily added to electron-deficient or electron-rich alkenes, giving the corresponding 1:1 hydropolyfluoroalkylation product or 1:1 adduct in high yields. This reaction provided a simple and convenient method to synthesize building blocks containing a CF3 or CF2 moiety.展开更多
A convenient and direct per(poly)fluoroalkylmethyl-introducing cyclopropanation reaction was described. In the presence of CrCl3/Fe, per(poly)fluoroalkyl iodides reacted with diethyl allylmalonate and its analogs to g...A convenient and direct per(poly)fluoroalkylmethyl-introducing cyclopropanation reaction was described. In the presence of CrCl3/Fe, per(poly)fluoroalkyl iodides reacted with diethyl allylmalonate and its analogs to give per(poly)fluoroalkylmethyl-substituted electrophilic cyclopropane derivatives in high yields. This reaction was considered to proceed by two steps: radical addition followed by cyclopropanation.展开更多
基金This work is supported by the National Natural Science Foundation of China （No.51372248, No.51432009 and No.51502297）, Instrument Developing Project of the Chinese Academy of Sciences （No.yz201421）, the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, China.
文摘A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.
文摘提出一种新型氧化还原液流电池:H2-Fe3+/Fe2+氧化还原液流电池。系统研究了Fe3+/Fe2+电对于未处理与热处理聚丙烯腈基石墨毡上的电化学性能及两种石墨毡组装电池充放电性能。实验结果表明:经热处理之后,石墨毡电化学反应活性面积变大,Fe3+/Fe2+电荷传递阻抗降低,从而降低了电池极化。以热处理石墨毡为电池正极,碳纸为负极组成电池,在50 m A/cm2充放电时,电压效率为87.43%,与用未处理石墨毡组装电池相比,电压效率提高11.82%,内阻降低50%。
基金Supported by the National Basic Research Program （2010CB630902, 2004CB619202） the National Natural Science Foundation of China （31070034, 30800011, 31260396）+1 种基金 the Knowledge Innovation Program of CAS （2AKSCX2-YW-JS401） the Reward Fund for Young Scientists of Shandong Province （2007BS08002） of China
文摘This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.
文摘Electrode material is one of the most important factors affecting the performance of supercapacitors, and electrolyte solution is another. In this work, electrochemical properties of hydroxide zinc carbonate composite electrode (HZC) in KOH + K3[Fe(CN)6] electrolyte were studied. It was proved that [Fe(CN)6]3−in electrolyte participated in electrochemical reactions and promoted electron transfer. The specific capacitance of HZC electrode was as high as 920.5 F·g−1 at 1.0 A·g−1 in 1 mol·L−1 KOH and 0.04 mol·L−1 K3[Fe(CN)6] electrolyte, which is 172.9% higher than that in KOH. The combination of HZC electrode and low alkalinity aqueous electrolyte provided the supercapacitor system with good capacitance performance, safety, and environmentally friendly.
基金Project supported by the National Natural Science Foundation of China.
文摘In the presence of CrCl3/Fe redox system, polyfluoropolyhaloethanes readily added to electron-deficient or electron-rich alkenes, giving the corresponding 1:1 hydropolyfluoroalkylation product or 1:1 adduct in high yields. This reaction provided a simple and convenient method to synthesize building blocks containing a CF3 or CF2 moiety.
基金Project supported by the National Natural Science Foundation of China.
文摘A convenient and direct per(poly)fluoroalkylmethyl-introducing cyclopropanation reaction was described. In the presence of CrCl3/Fe, per(poly)fluoroalkyl iodides reacted with diethyl allylmalonate and its analogs to give per(poly)fluoroalkylmethyl-substituted electrophilic cyclopropane derivatives in high yields. This reaction was considered to proceed by two steps: radical addition followed by cyclopropanation.
