NH 3 activated electrode is placed in front of the electrode system of pulse corona discharge plasma. There are nozzles on the electrode. Positive DC high\|voltage is applied on the nozzle\|plate gap. NH\-3 is in...NH 3 activated electrode is placed in front of the electrode system of pulse corona discharge plasma. There are nozzles on the electrode. Positive DC high\|voltage is applied on the nozzle\|plate gap. NH\-3 is injected into the reactor through nozzles, at the same time, activated and treated. These nozzles were proposed in order to make the additional gas pass through corona discharge regions near the tip of nozzles and increase the mount of radicals. The aim is to improve the De\|SO\-2 efficiency by pulse discharge plasma in flue gas. The following topics are investigated and discussed in the paper: De\|SO\-2 effect of single NH\-3\|activated electrode, De\|SO\-2 effect of activated NH\-3, the relationship between stoichiometric ratio of NH\-3 to SO\-2 and De\|SO\-2 effect of activated NH\-3, mechanism of activated NH\-3 De\|SO\-2 effect. The experimental result indicates that the De\|SO\-2 efficiency can be increased 5%—10% by activated NH\-3 on the original base of De\|SO\-2 efficiency.展开更多
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functi...Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functionalization of unactivated methylene C(sp^(3))—H bonds. A variety of reactions, including arylation, alkylation, alkenylation/alkynylation, acetoxylation, amination, halogenation, borylation, and silylation reactions, have been discussed. Due to the inert properties, methylene C(sp^(3))—H functionalization reaction usually relies on the use of directing group strategies, which can not only control regioselectivity but also address low reactivity issue. Various directing groups, including strongly coordinating bidentate auxiliaries and weakly coordinating innate functional groups, have proven to be effective for enabling methylene C(sp^(3))—H functionalization.展开更多
To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The ...To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The denitration activities of the Fe-V/AC catalysts in the range of 150-300℃ were evaluated.The increase in denitration temperature leads to the highest and fastest recovery rate of NO conversion in the 10Fe-15V/AC catalyst.However,more metal oxides were attached to the catalyst surface as the V loading increased,and the accumulation occurred.The surface-active components are FeO,Fe_(2)O_(3),Fe_(3)O_(4),VO_(2),and V_(2)O_(5).In addition,the increase in the V loading induced a series of modification effects.A large amount of Fe^(3+)was reduced to Fe^(2+),and a large amount of V^(4+)was oxidized to V^(5+).The surface oxygen species(O_(α))were transformed into lattice oxygen(O_(β)).The presence of a large amount of V species deteriorated the pore-structure parameters and destroyed the oxygen-containing functional groups.Increasing the V loading can effectively increase the Lewis acid sites,thereby promoting NH_(3) adsorption and NO reduction and increasing the stretching vibration of weakly adsorbed ammonia species on the catalyst.The NH_(3) adsorption process produces a notable increase in the concentration of monodentate nitrite(NH_(4)^(+)).The NH_(3)-SCR denitration mechanism of the Fe-V/AC catalyst includes reaction gas adsorption,catalytic denitration of metal active components,and gas desorption.展开更多
The newly invented farming method, Fenlong technology, uses self-propelled powder-ridging mechanical screw-type drill for the deep-cultivation and deep tillage of soil, and it can enhance the double tillering depth th...The newly invented farming method, Fenlong technology, uses self-propelled powder-ridging mechanical screw-type drill for the deep-cultivation and deep tillage of soil, and it can enhance the double tillering depth than the conventional tillage. Moreover, the tilth soil is uniform in size and in small, broken bits and loose. It expands the new soil ＂four warehouses＂ （namely soil nutrient warehouse, water warehouse, oxygen warehouse and microbial warehouse）, and under the conditions of ＂three no increase＂ in chemical fertilizer and pesticide, irrigation water and labor input, various crops show a increase of 10%-30% in yield （average increase by 25.48% in the 23 rice, wheat and corn planting areas of several provinces）, 5% in quality, and 1 time in water retention. And the sustainable production-increasing ef- fect lasts 2-3 years after once Fenlong tillage, with the comparative efficiency reaching about 20%. It is suggested using Fenlong to activate the arable land, saline land grassland and rivers resources, so as to drive the construction of green agriculture ＂3＋1＂ industrial system, which can promote the realization of the increases in available agricultural resource stock, quality food resource stock and available water resource stock in China and even in the world, realize the ＂two responses＂ to ecological environment deterioration and climate warming, and achieve the harmonious coexistence of human beings and nature.展开更多
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
文摘NH 3 activated electrode is placed in front of the electrode system of pulse corona discharge plasma. There are nozzles on the electrode. Positive DC high\|voltage is applied on the nozzle\|plate gap. NH\-3 is injected into the reactor through nozzles, at the same time, activated and treated. These nozzles were proposed in order to make the additional gas pass through corona discharge regions near the tip of nozzles and increase the mount of radicals. The aim is to improve the De\|SO\-2 efficiency by pulse discharge plasma in flue gas. The following topics are investigated and discussed in the paper: De\|SO\-2 effect of single NH\-3\|activated electrode, De\|SO\-2 effect of activated NH\-3, the relationship between stoichiometric ratio of NH\-3 to SO\-2 and De\|SO\-2 effect of activated NH\-3, mechanism of activated NH\-3 De\|SO\-2 effect. The experimental result indicates that the De\|SO\-2 efficiency can be increased 5%—10% by activated NH\-3 on the original base of De\|SO\-2 efficiency.
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
文摘Although transition metal-catalyzed methylene C(sp^(3))—H functionalization is a great challenge, it has made noticeable progress in recent years. This review specifically describes Pd-catalyzed intermolecular functionalization of unactivated methylene C(sp^(3))—H bonds. A variety of reactions, including arylation, alkylation, alkenylation/alkynylation, acetoxylation, amination, halogenation, borylation, and silylation reactions, have been discussed. Due to the inert properties, methylene C(sp^(3))—H functionalization reaction usually relies on the use of directing group strategies, which can not only control regioselectivity but also address low reactivity issue. Various directing groups, including strongly coordinating bidentate auxiliaries and weakly coordinating innate functional groups, have proven to be effective for enabling methylene C(sp^(3))—H functionalization.
基金financially supported by National Natural Science Foundation of China(No.52264043).
文摘To explore the denitration mechanism of iron-vanadium/activated carbon(Fe-V/AC)catalysts in ammonia-selective catalytic reduction(NH_(3)-SCR),the physicochemical properties of Fe-V/AC catalysts were characterized.The denitration activities of the Fe-V/AC catalysts in the range of 150-300℃ were evaluated.The increase in denitration temperature leads to the highest and fastest recovery rate of NO conversion in the 10Fe-15V/AC catalyst.However,more metal oxides were attached to the catalyst surface as the V loading increased,and the accumulation occurred.The surface-active components are FeO,Fe_(2)O_(3),Fe_(3)O_(4),VO_(2),and V_(2)O_(5).In addition,the increase in the V loading induced a series of modification effects.A large amount of Fe^(3+)was reduced to Fe^(2+),and a large amount of V^(4+)was oxidized to V^(5+).The surface oxygen species(O_(α))were transformed into lattice oxygen(O_(β)).The presence of a large amount of V species deteriorated the pore-structure parameters and destroyed the oxygen-containing functional groups.Increasing the V loading can effectively increase the Lewis acid sites,thereby promoting NH_(3) adsorption and NO reduction and increasing the stretching vibration of weakly adsorbed ammonia species on the catalyst.The NH_(3) adsorption process produces a notable increase in the concentration of monodentate nitrite(NH_(4)^(+)).The NH_(3)-SCR denitration mechanism of the Fe-V/AC catalyst includes reaction gas adsorption,catalytic denitration of metal active components,and gas desorption.
基金Supported by the Major Special Project for Science and Technology of Guangxi Province(Guike AA16380017)the Key Science and Technology Planning Project for Agriculture of Guangxi Province(201503)the Achievements Transformation of Guangxi Academy of Agricultural Sciences(Nongzhuancheng 201405)~~
文摘The newly invented farming method, Fenlong technology, uses self-propelled powder-ridging mechanical screw-type drill for the deep-cultivation and deep tillage of soil, and it can enhance the double tillering depth than the conventional tillage. Moreover, the tilth soil is uniform in size and in small, broken bits and loose. It expands the new soil ＂four warehouses＂ （namely soil nutrient warehouse, water warehouse, oxygen warehouse and microbial warehouse）, and under the conditions of ＂three no increase＂ in chemical fertilizer and pesticide, irrigation water and labor input, various crops show a increase of 10%-30% in yield （average increase by 25.48% in the 23 rice, wheat and corn planting areas of several provinces）, 5% in quality, and 1 time in water retention. And the sustainable production-increasing ef- fect lasts 2-3 years after once Fenlong tillage, with the comparative efficiency reaching about 20%. It is suggested using Fenlong to activate the arable land, saline land grassland and rivers resources, so as to drive the construction of green agriculture ＂3＋1＂ industrial system, which can promote the realization of the increases in available agricultural resource stock, quality food resource stock and available water resource stock in China and even in the world, realize the ＂two responses＂ to ecological environment deterioration and climate warming, and achieve the harmonious coexistence of human beings and nature.
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.
