Carbon nitride (CN) in CN encapsulated Ni/ Al2O3 (denoted as CN/Ni/Al2O3) catalyst was evidenced previously as a material in electron-rich state and possessed H-2-dissociative adsorption activity due to the electron d...Carbon nitride (CN) in CN encapsulated Ni/ Al2O3 (denoted as CN/Ni/Al2O3) catalyst was evidenced previously as a material in electron-rich state and possessed H-2-dissociative adsorption activity due to the electron doping effect from underlying nickel. In this report, iron oxide loaded on the CN/Ni/Al2O3 was synthesized and investigated by Fischer-Tropsch (F-T) synthesis to test the special effect of electron-rich support on the catalytic activity of iron oxide. The Fe/CN/Al2O3 and CN/Ni/Al2O3 samples were accordingly synthesized for comparison. In Fe/CN/Ni/Al2O3, the iron oxide was reduced to magnetite by syngas as evidenced by the in-situ XPS measurements and XRD pattern of used catalyst. Compared with Fe/CN/Al2O3, more light hydrocarbons over Fe/CN/Ni/Al2O3 were observed. It should be understood by the interaction between iron oxide and support mainly due to the effect of electron-rich state and thus enhanced H-2 adsorption ability. In addition, such a novel support facilitated the CO conversion and retarded the water-gas shift reaction and CO2 formation. The new type of adjustment on electronic state should be useful for novel catalyst design. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results ...Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.展开更多
The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-...The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.展开更多
The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists...The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists in these molecules.展开更多
Rationally constructed new catalyst can promote carbon dioxide reduction reaction(CO_(2)RR)to valuable carbo-naceous fuels such as formate and CO,providing a promising strategy for low CO_(2)emissions.Herein,the syn-t...Rationally constructed new catalyst can promote carbon dioxide reduction reaction(CO_(2)RR)to valuable carbo-naceous fuels such as formate and CO,providing a promising strategy for low CO_(2)emissions.Herein,the syn-thesized Ni_(3)S_(2)@C as a highly efficient electro-catalyst exhibits remarkable selectivity for formate with 73.9%faradaic efficiency(FE)at-0.7 V vs.RHE.At high applied potential,it shows a high syngas evolution with CO/H_(2)ratios(0.54-3.15)that are suitable for typical downstream thermochemical reactions.The experimental and theoretical analyses demonstrate that the electron-rich Ni^(2+)in Ni_(3)S_(2)enhances the adsorption behavior of*OCHO intermediate,reduces the energy barrier of the formation of intermediates,and improves the selectivity of the formate product.Attenuated total reflection surface-enhanced infrared absorption spectra conducted in situ show that*OCHO intermediate is more likely to be generated and adsorbed on Ni_(3)S_(2),enhancing the selectivity and activity of the formate product.展开更多
The arylation of C(sp^(3))-H bonds has been a priority research topic in organic synthesis.Minsici reactions have been the powerful methods for C(sp^(3))-C(sp^(2))bonds formation.Despite its mature development,the sco...The arylation of C(sp^(3))-H bonds has been a priority research topic in organic synthesis.Minsici reactions have been the powerful methods for C(sp^(3))-C(sp^(2))bonds formation.Despite its mature development,the scopes of arenes are usually suitable for elec-tron-deficient heterocyclic compounds,rather than electron-rich arenes.Herein,we report an electrooxidation-induced alkylation of electron-rich arenes with H_(2) evolution under exogenous oxidant-free conditions,avoiding the utilization of metal catalysts.This pro-tocol is well performed with various electron-rich aniline derivatives and nitrogen-containing heterocyclic compounds.We anticipate that this electro-oxidative C(sp^(3))-H arylation represents an important expansion for the classic arenes alkylation,thereby proving an attractive strategy for the developments of radical cross-coupling chemistry.展开更多
A series of V-type chromophores with electron-rich heterocyclevinylene bridges have been synthesized via Wittig-Horner-Emmons and Vilsmeier reactions.All the target chromophores showed strong one-photon and two-photon...A series of V-type chromophores with electron-rich heterocyclevinylene bridges have been synthesized via Wittig-Horner-Emmons and Vilsmeier reactions.All the target chromophores showed strong one-photon and two-photon excited emission,and their electron properties could be tuned by using different heterocycles such as furan,thiophene and pyrrole moieties in I-III.The maximum two-photon absorption (TPA) cross sections occurred at 760 nm and were measured to be in the range of 400-800 GM.展开更多
The application ot the sulfinatodehalogenation reaction system for the perfluoroalkylation of electron-rich aromatics is further studied.It was shown that perfluoroalkyl iodides reacted with polyhydric phenols,N,N-dia...The application ot the sulfinatodehalogenation reaction system for the perfluoroalkylation of electron-rich aromatics is further studied.It was shown that perfluoroalkyl iodides reacted with polyhydric phenols,N,N-dialkylanilines,2,5-dimethylpyrrole,N-methylpyrrole initiated by Na_2S_2O_4- NaHCO_3 gave the corresponding perfluoroalkylated products in moderate to good yields.展开更多
Herein,we examine the performance of dye-sensitized solar cells containing five D-π-A organic dyes designed by systematic modification of π-bridge size and geometric structure.Each dye has a simple push-pull structu...Herein,we examine the performance of dye-sensitized solar cells containing five D-π-A organic dyes designed by systematic modification of π-bridge size and geometric structure.Each dye has a simple push-pull structure with a triarylamino group as an electron donor,bithiophene-4,4-dimethyl-4 H-cyclopenta 1,2-b:5,4-b’]dithiophene(M11),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophenethiophene(M12),thiophene-4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M13),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene-benzene(M14),and 4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M15)units asπ-bridges,and cyanoacrylic acid as an electron acceptor/anchor.The extension of theπ-bridge linkage favors wide-range absorption but,because of the concomitant molecular volume increase,hinders the efficient adsorption of dyes on the TiO_(2) film surface.Hence,higher loadings are achieved for smaller dye molecules,resulting in(i)a shift of the TiO_(2) conduction band edge to more negative values,(ii)a greater photocurrent,and(iii)suppressed charge recombination between the photoanode and the redox couple in the electrolyte.Consequently,under one-sun equivalent illumination(AM 1.5 G,100 mW/cm^(2)),the highest photovoltage,photocurrent,and conversion efficiency(η=7.19%)are observed for M15,which has the smallest molecular volume among M series dyes.展开更多
Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as ...Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as alternatives to Pt-based catalysts for the oxygen reduction reaction(ORR).In this study,commercial silicon carbide(SiC)was modified through surface oxidization(O-SiC)to support the use of Pd nanoparticles(Pd NPs)as electrocatalysts for ORR.The obtained Pd/O-SiC catalysts exhibited better ORR activity,stronger durability,and higher resistance to methanol poisoning than that exhibited by commercial Pt/C.The role of the support in enhancing the ORR performance,especially the oxidization of SiC surfaces,was discussed in detail based on the experimental characterizations and density functional theory calculations.The underlying mechanism of the superior ORR performance of Pd/O-SiC catalysts was attributed to the charge transfer from SiC_(x)O_(y)to Pd NPs on the surfaces of SiC and the strong metal–support interactions(SMSIs)between Pd and SiC_(x)O_(y).The charge transfer enhanced the ORR activity by inducing electron-rich Pd,increased the adsorption of the key intermediate OOH,and decreased the Gibbs free energy of the critical ORR step.Furthermore,SMSIs enhanced the ORR stability of the Pd/O-SiC catalyst.This study provided a facile route for designing and developing highly active Pd-based ORR electrocatalysts.展开更多
基金supported by the Ministry of Science and Technology of China (2009CB623504)the National Science Foundation of China (20673054,21273107)Sinopec Shanghai Research Institute of Petrochemical Technology
文摘Carbon nitride (CN) in CN encapsulated Ni/ Al2O3 (denoted as CN/Ni/Al2O3) catalyst was evidenced previously as a material in electron-rich state and possessed H-2-dissociative adsorption activity due to the electron doping effect from underlying nickel. In this report, iron oxide loaded on the CN/Ni/Al2O3 was synthesized and investigated by Fischer-Tropsch (F-T) synthesis to test the special effect of electron-rich support on the catalytic activity of iron oxide. The Fe/CN/Al2O3 and CN/Ni/Al2O3 samples were accordingly synthesized for comparison. In Fe/CN/Ni/Al2O3, the iron oxide was reduced to magnetite by syngas as evidenced by the in-situ XPS measurements and XRD pattern of used catalyst. Compared with Fe/CN/Al2O3, more light hydrocarbons over Fe/CN/Ni/Al2O3 were observed. It should be understood by the interaction between iron oxide and support mainly due to the effect of electron-rich state and thus enhanced H-2 adsorption ability. In addition, such a novel support facilitated the CO conversion and retarded the water-gas shift reaction and CO2 formation. The new type of adjustment on electronic state should be useful for novel catalyst design. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金the Renmin University of China and the National Natural Science Foundation of China(Nos.20542009 and 20672139)for financial support.
文摘Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.
文摘The ground state spins coupled through electron-rich rings of bicarbenes and binitreneshave been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic couplingexists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.
文摘The characters of coupling between two doublet NO radicals linked through electron-rich rings have been studied. The results demonstrate that the molecules have triplet ground states, and ferromagnetic coupling exists in these molecules.
基金the National Natural Science Foundation of China(Nos.52302272 and 22376110)the Taishan Scholars Program(No.tsqn202211124)+2 种基金the Natural Science Foundation of Shandong Province(No.ZR2022QB023)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Marine Polysaccharides Fibers-based Energy Materials)the State Key Laboratory of Bio-Fibers and Eco-Textiles,Qingdao University(Nos.ZKT10,GZRC202006,ZFZ201809,and ZDKT202105).
文摘Rationally constructed new catalyst can promote carbon dioxide reduction reaction(CO_(2)RR)to valuable carbo-naceous fuels such as formate and CO,providing a promising strategy for low CO_(2)emissions.Herein,the syn-thesized Ni_(3)S_(2)@C as a highly efficient electro-catalyst exhibits remarkable selectivity for formate with 73.9%faradaic efficiency(FE)at-0.7 V vs.RHE.At high applied potential,it shows a high syngas evolution with CO/H_(2)ratios(0.54-3.15)that are suitable for typical downstream thermochemical reactions.The experimental and theoretical analyses demonstrate that the electron-rich Ni^(2+)in Ni_(3)S_(2)enhances the adsorption behavior of*OCHO intermediate,reduces the energy barrier of the formation of intermediates,and improves the selectivity of the formate product.Attenuated total reflection surface-enhanced infrared absorption spectra conducted in situ show that*OCHO intermediate is more likely to be generated and adsorbed on Ni_(3)S_(2),enhancing the selectivity and activity of the formate product.
基金the National Key R&D Program of China(No.2021YFA1500104)the National Natural Science Foundation of China(No.22031008)the Science Foundation of Wuhan(No.2020010601012192)。
文摘The arylation of C(sp^(3))-H bonds has been a priority research topic in organic synthesis.Minsici reactions have been the powerful methods for C(sp^(3))-C(sp^(2))bonds formation.Despite its mature development,the scopes of arenes are usually suitable for elec-tron-deficient heterocyclic compounds,rather than electron-rich arenes.Herein,we report an electrooxidation-induced alkylation of electron-rich arenes with H_(2) evolution under exogenous oxidant-free conditions,avoiding the utilization of metal catalysts.This pro-tocol is well performed with various electron-rich aniline derivatives and nitrogen-containing heterocyclic compounds.We anticipate that this electro-oxidative C(sp^(3))-H arylation represents an important expansion for the classic arenes alkylation,thereby proving an attractive strategy for the developments of radical cross-coupling chemistry.
基金the National Natural Science Foundation of China (21002075 and 21034006) for financial support
文摘A series of V-type chromophores with electron-rich heterocyclevinylene bridges have been synthesized via Wittig-Horner-Emmons and Vilsmeier reactions.All the target chromophores showed strong one-photon and two-photon excited emission,and their electron properties could be tuned by using different heterocycles such as furan,thiophene and pyrrole moieties in I-III.The maximum two-photon absorption (TPA) cross sections occurred at 760 nm and were measured to be in the range of 400-800 GM.
基金the National Natural Science Foundation of China.Part ⅩⅩⅢ in this series,see Huang,W.-Y.Zhuang,J.-L.,Chinese J.Chem.,9,270 (1991).
文摘The application ot the sulfinatodehalogenation reaction system for the perfluoroalkylation of electron-rich aromatics is further studied.It was shown that perfluoroalkyl iodides reacted with polyhydric phenols,N,N-dialkylanilines,2,5-dimethylpyrrole,N-methylpyrrole initiated by Na_2S_2O_4- NaHCO_3 gave the corresponding perfluoroalkylated products in moderate to good yields.
基金supported by Basic Science Research through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2017R1D1A1B03035077)also supported by Research Program(2018R1A2B2006708)+1 种基金Technology Development Program to Solve Climate Changes(2015M1A2A2057062)funded by the National Research Foundation under the Ministry of Science and ICT,Republic of Koreasupported by the Defense Challengeable Future Technology Program of the Agency for Defense Development,Republic of Korea。
文摘Herein,we examine the performance of dye-sensitized solar cells containing five D-π-A organic dyes designed by systematic modification of π-bridge size and geometric structure.Each dye has a simple push-pull structure with a triarylamino group as an electron donor,bithiophene-4,4-dimethyl-4 H-cyclopenta 1,2-b:5,4-b’]dithiophene(M11),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophenethiophene(M12),thiophene-4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M13),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene-benzene(M14),and 4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M15)units asπ-bridges,and cyanoacrylic acid as an electron acceptor/anchor.The extension of theπ-bridge linkage favors wide-range absorption but,because of the concomitant molecular volume increase,hinders the efficient adsorption of dyes on the TiO_(2) film surface.Hence,higher loadings are achieved for smaller dye molecules,resulting in(i)a shift of the TiO_(2) conduction band edge to more negative values,(ii)a greater photocurrent,and(iii)suppressed charge recombination between the photoanode and the redox couple in the electrolyte.Consequently,under one-sun equivalent illumination(AM 1.5 G,100 mW/cm^(2)),the highest photovoltage,photocurrent,and conversion efficiency(η=7.19%)are observed for M15,which has the smallest molecular volume among M series dyes.
文摘Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as alternatives to Pt-based catalysts for the oxygen reduction reaction(ORR).In this study,commercial silicon carbide(SiC)was modified through surface oxidization(O-SiC)to support the use of Pd nanoparticles(Pd NPs)as electrocatalysts for ORR.The obtained Pd/O-SiC catalysts exhibited better ORR activity,stronger durability,and higher resistance to methanol poisoning than that exhibited by commercial Pt/C.The role of the support in enhancing the ORR performance,especially the oxidization of SiC surfaces,was discussed in detail based on the experimental characterizations and density functional theory calculations.The underlying mechanism of the superior ORR performance of Pd/O-SiC catalysts was attributed to the charge transfer from SiC_(x)O_(y)to Pd NPs on the surfaces of SiC and the strong metal–support interactions(SMSIs)between Pd and SiC_(x)O_(y).The charge transfer enhanced the ORR activity by inducing electron-rich Pd,increased the adsorption of the key intermediate OOH,and decreased the Gibbs free energy of the critical ORR step.Furthermore,SMSIs enhanced the ORR stability of the Pd/O-SiC catalyst.This study provided a facile route for designing and developing highly active Pd-based ORR electrocatalysts.
