This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(D...This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.展开更多
[目的]3-(3′,4′-次甲二氧苯基)-N-正丙基丙烯酰胺是具有广谱抑菌活性的化合物,将其研制成优良环保剂型悬浮剂,可为实现田间应用提供技术依据。[方法]采用湿法研磨制备了12种不同配方的悬浮剂,通过质量指标检测确定最佳配方,测定其表...[目的]3-(3′,4′-次甲二氧苯基)-N-正丙基丙烯酰胺是具有广谱抑菌活性的化合物,将其研制成优良环保剂型悬浮剂,可为实现田间应用提供技术依据。[方法]采用湿法研磨制备了12种不同配方的悬浮剂,通过质量指标检测确定最佳配方,测定其表面张力及其在黄瓜叶面的动态接触角,并开展了防治黄瓜白粉病田间药效试验。[结果]最佳配方为3-(3′,4′-次甲二氧苯基)-N-正丙基丙烯酰胺40%(折百)、S043%、D4252%、W071%、乙二醇3%、硅酸镁铝0.4%、黄原胶0.12%、B150.12%、消泡剂X600.3%、水补足。此悬浮剂在有效成分0.27 g a.i./L时的表面张力以及在黄瓜叶面的动态接触角均小于对照药剂40%苯醚甲环唑SC,表明其具有良好的润湿性能。在有效成分0.27 g a.i./L下的防效为88.38%,与对照药剂25%嘧菌酯SC 0.20 g a.i./L相当,且对黄瓜安全。[结论]制备悬浮剂为类白色均匀悬浮液,流动性好,粒径合格,悬浮率稳定在98.5%左右,pH为4.09,黏度为452 mPa·s,入水分散性合格,热储、低温及冻融稳定性良好,未出现沉淀,各项指标均达标,对黄瓜白粉病防效优良,具有良好的开发应用前景。展开更多
Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3...Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.展开更多
Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunctio...Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.展开更多
A series of graphitic-C3N4/ZnS（g-C3N4/ZnS） supercapacitor electrode materials have been prepared via a one-step calcination process of zinc acetate/thiourea with different mass ratios under nitrogen atmosphere. The ...A series of graphitic-C3N4/ZnS（g-C3N4/ZnS） supercapacitor electrode materials have been prepared via a one-step calcination process of zinc acetate/thiourea with different mass ratios under nitrogen atmosphere. The optimized g-C3N4/ZnS composite shows a highest specific capacitance of 497.7 F/g at 1 A/g and good cycling stability with capacitance retention of 80.4% at 5 A/g after 1000 cycles. Moreover, gC3N4/ZnS composites display an improved supercapacitor performance in terms of specific capacitance compared to the pure g-C3N4 and ZnS. In addition, our designed symmetric supercapacitor device based on g-C3N4/ZnS composite electrodes can exhibit an energy density of 10.4 Wh/kg at a power density of 187.3 W/kg. As a result, g-C3N4/ZnS composites are expected to be a prospective material for supercapacitors and other energy storage applications.展开更多
基金Supported by the National Key Research and Development Program of China(2022YFB4301400)the Basic Science(Natural Science)Research Project for Higher Education Institutions in Jiangsu Province(24KJD580001)。
文摘This study systematically investigates the cyclization reaction mechanisms between n-C_(4)H_(3)(1-buten-3-yn-1-yl)and i-C_(4)H_(3)(2-buten-3-yn-1-yl)radicals with acetylene(C_(2)H_(2))using density functional theory(DFT)and transition state theory(TST).The results reveal that the reaction of n-C_(4)H_(3)with acetylene proceeds via a radical chain mechanism through an additioncyclization pathway,yielding phenyl(sixmembered ring),fulvenyl(five-membered ring),and four-membered ring intermediates.The product formation rates follow the order:fulvenyl(five-membered ring)>phenyl(six-membered ring)>four-membered ring.For i-C_(4)H_(3),the intermediate structures depend on the carbon position of i-C_(4)H_(3)where acetylene addition occurs:addition at the C2 position predominantly generates fulvenyl(five-membered ring)as the primary product,whereas addition at the C4 position may lead to phenyl(six-membered ring),fulvenyl(five-membered ring),or four-membered ring intermediates,with the four-membered ring forming most rapidly and the six-membered ring the slowest.Theoretical analyses demonstrate that the selectivity of reaction pathways is primarily governed by structural differences between the isomers.This work provides atomic-scale insights into the cyclization processes between acetylene and C_(4)H_(3)species,establishing a foundation for refining models of soot precursor formation.
文摘[目的]3-(3′,4′-次甲二氧苯基)-N-正丙基丙烯酰胺是具有广谱抑菌活性的化合物,将其研制成优良环保剂型悬浮剂,可为实现田间应用提供技术依据。[方法]采用湿法研磨制备了12种不同配方的悬浮剂,通过质量指标检测确定最佳配方,测定其表面张力及其在黄瓜叶面的动态接触角,并开展了防治黄瓜白粉病田间药效试验。[结果]最佳配方为3-(3′,4′-次甲二氧苯基)-N-正丙基丙烯酰胺40%(折百)、S043%、D4252%、W071%、乙二醇3%、硅酸镁铝0.4%、黄原胶0.12%、B150.12%、消泡剂X600.3%、水补足。此悬浮剂在有效成分0.27 g a.i./L时的表面张力以及在黄瓜叶面的动态接触角均小于对照药剂40%苯醚甲环唑SC,表明其具有良好的润湿性能。在有效成分0.27 g a.i./L下的防效为88.38%,与对照药剂25%嘧菌酯SC 0.20 g a.i./L相当,且对黄瓜安全。[结论]制备悬浮剂为类白色均匀悬浮液,流动性好,粒径合格,悬浮率稳定在98.5%左右,pH为4.09,黏度为452 mPa·s,入水分散性合格,热储、低温及冻融稳定性良好,未出现沉淀,各项指标均达标,对黄瓜白粉病防效优良,具有良好的开发应用前景。
基金supported by the National Natural Science Foun-dation of China(No.62004143)the Key R&D Program of Hubei Province(No.2022BAA084)the Natural Science Foundation of Hubei Province(No.2021CFB133).
文摘Doping engineering is an effective strategy for graphitic carbon nitride(g-C_(3)N_(4))to improve its photocat-alytic hydrogen evolution reaction(HER)performance.In this work,a novel nitrogen and sulfur co-doped g-C_(3)N_(4)(N,S-g-C_(3)N_(4))is elaborately designed on the basis of theoretical predictions of first-principle density functional theory(DFT).The calculated Gibbs free energy of adsorbed hydrogen(ΔGH∗)for N,S-g-C_(3)N_(4) at the N-doping active sites is extremely close to zero(0.01 eV).Inspired by the theoretical predictions,the N,S-g-C_(3)N_(4) is successfully fabricated through ammonia-rich pyrolysis synthesis strategy,in which ammonia is in-situ obtained by pyrolyzing melamine.Subsequent characterizations indicate that the N,S-g-C_(3)N_(4) possesses high specific surface area,outstanding light utilization,good hydrophilicity,and efficient carrier transfer efficiency.Consequently,the N,S-g-C_(3)N_(4) displays an extremely high H2 evolution rate of 8269.9μmol g−1 h−1,achieves an apparent quantum efficiency(AQE)of 3.24%,and also possesses outsatnding durability.Theoretical calculations further demonstrate that N and S dopants can not only introduce doping energy level to reduce the band gap,but also induce charge redistribution to facilitate hydrogen adsorption,thus promoting the photocatalytic HER process.Moreover,femtosecond transient absorption(fs-TA)spectroscopy further corroborates the efficient photogenerated carrier transport of N,S-g-C_(3)N_(4).This research highlights a promising and reliable strategy to achieve superior photocatalytic activity,and exhibits significant guidance for precise designing high-efficiency photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52362012,42077162,51978323)Natural Science Foundation of Jiangxi Province(No.2022ACB203014)+4 种基金Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(Nos.20213BCJ22018,20232BCJ22048)Natural Science Project of the Educational Department in Jiangxi Province(No.GJJ2201121)Natural Science Foundation of Nanchang Hangkong University(No.EA202202256)Educational Reform Project of Jiangxi Province(No.JXYJG-2022-135)Nanchang Hangkong University Educational Reform Project(Nos.sz2214,sz2213,JY22017,KCPY1806)。
文摘Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.
基金supported by the National Nature Science Foundations of China (Grant no. 51372212)
文摘A series of graphitic-C3N4/ZnS（g-C3N4/ZnS） supercapacitor electrode materials have been prepared via a one-step calcination process of zinc acetate/thiourea with different mass ratios under nitrogen atmosphere. The optimized g-C3N4/ZnS composite shows a highest specific capacitance of 497.7 F/g at 1 A/g and good cycling stability with capacitance retention of 80.4% at 5 A/g after 1000 cycles. Moreover, gC3N4/ZnS composites display an improved supercapacitor performance in terms of specific capacitance compared to the pure g-C3N4 and ZnS. In addition, our designed symmetric supercapacitor device based on g-C3N4/ZnS composite electrodes can exhibit an energy density of 10.4 Wh/kg at a power density of 187.3 W/kg. As a result, g-C3N4/ZnS composites are expected to be a prospective material for supercapacitors and other energy storage applications.
