The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c...The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.展开更多
An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described. Eight 2-heteroaryl- and 2,7-diheteroaryl-1,8-naphthyridine derivatives were obtained through palladium-catalyzed...An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described. Eight 2-heteroaryl- and 2,7-diheteroaryl-1,8-naphthyridine derivatives were obtained through palladium-catalyzed C-N-coupling reactions of chloronaphthyridines with imidazole, benzimidazole, morpholine, 3,5-dimethylpyrazole, and phthalimide in moderate to good yields.展开更多
The complex reaction system of the coal gasification coupling C1 reaction was analyzed based on the principles of thermodynamics. The results show that an increase in the temperature is beneficial to the generation of...The complex reaction system of the coal gasification coupling C1 reaction was analyzed based on the principles of thermodynamics. The results show that an increase in the temperature is beneficial to the generation of hydrocarbons with high carbon-atom contents, in which the alkane yield is higher than the alkene yield. The complex reaction system consisting of C, H20, CO, CO2, H2, C2H4, C3H6 and C4Hs was studied, and the obtained results indicated that when the maximum mole fraction content of C2-C4 olefins was regarded as the optimized objective function, the optimum temperature was approximately 648 K, the pressure was 0.1 MPa, the feed ratio was approximately 0.6, and the maximum mole fraction content of C2-C4 olefins was approximately 28.24%. The thermodynamic simulation and calculation of the complex reaction system can provide a basis for the determination and optimization of actual process conditions and are therefore of great theoretical and practical significance.展开更多
The coupled reaction of methyl acetate and n‐hexane was carried out over a HZSM‐5 catalyst.In addition to a thermal coupling effect,systematic variations in the product distribution were also observed in the coupled...The coupled reaction of methyl acetate and n‐hexane was carried out over a HZSM‐5 catalyst.In addition to a thermal coupling effect,systematic variations in the product distribution were also observed in the coupled system.The bezene‐toluene‐xylene(BTX)selectivity was remarkably improved while the H2,CO,and CO2 selectivity decreased.Rapid deactivation of the catalyst was observed,caused by the extremely high reactivity of methyl acetate,which was alleviated after adding n‐hexane.These results indicated that a coupling effect exists in this system.A detailed pathway for the coupled system is suggested based on the analysis of the surface species,carbonaceous species deposited on the catalyst,as well as the product selectivity changes.The good match between the"hydrogen deficiency"of methyl acetate and the"hydrogen richness"of n‐hexane is consistent with the observed coupling effect.展开更多
Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized ...Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized and subse- quently used as macroinitiators for atom transfer radial polymerization (ATRP) of n-butyl acrylate (n-BA) and ethyl acrylate (EA). Both the polymerization processes were controlled and the polymers were characterized by 1H NMR, gel permeation chromatography (GPC) and thermal properties, which confirmed the successful synthesis of all the poly-mers. The microphase separated behaviors of the poly (4-butyltriarylamine)-block-poly (butyl acrylate) (PBTPA-b-PBA) were examined by AFM in the film showing phase separation structures for all the polymers. The photorefractive property of the composite based on PBTPA-b-PBA block copolymer was evaluated by two-beam coupling experiment. A relative high gain coefficient of 42.7 cm?1 was obtained at the electric field of 31 V/?m.展开更多
The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoreti...The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoretical understanding of reaction mechanism was relative illusive,which is indispensable to rationally design of efficient catalysts.Besides,tuning the reaction microenvironment along with the scale-up device development is essential to promote the industrial deployment of electrocatalytic nitrate conversion,while relative research was overlooked.In this regard,recent advances in ammonia synthesis are firstly summarized,including the identification of active sites,exploration of the underlying reaction mechanisms,electrolyzer design and technical-economic analysis.Furthermore,electrocatalytic C–N coupling based on NO_(3)RR to produce higher-value products such as urea and amino acids are also reviewed,to extend the application potential and economic feasibility.Finally,we highlight the existing challenges and the demand of future research for NO_(3)RR.This review anticipates to provide insights into synthesis of high-value products via NO_(3)RR,bridging the gap from laboratory research to industrial fabrication.展开更多
Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic pr...Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.展开更多
Herein,we for the first time demonstrate the synthesis of exfoliated C4N nanosheets via a top-down approach and exploit their use as a new class of organic polymeric catalyst for the oxygen reduction reaction(ORR).The...Herein,we for the first time demonstrate the synthesis of exfoliated C4N nanosheets via a top-down approach and exploit their use as a new class of organic polymeric catalyst for the oxygen reduction reaction(ORR).The obtained C4N nanosheets are semi-conductive with a small band gap of 1.41 eV and contain abundant pyrazine-nitrogen moieties uniformly distributed throughout C4N.Density function theory calculations reveal that the intramolecular charge transfer induced by pyrazine-nitrogen in C4N enables effective charge redistribution to activate the conjugated structure and facilitate the oxygen adsorption,while the exfoliated sheet-like C4N formation renders improved electrochemical active surface area and results in high exposure of active sites.As a result,despite the bulk C4N is not active,the sheet-like C4N yield markedly improved ORR performance,even on a par with the commercial Pt/C catalyst.Our recent findings not only enrich the family members of two-dimensional conjugated polymer nanosheets but also open up new opportunity to explore new metal-free organic polymeric materials for efficient oxygen reduction catalysis and beyond.展开更多
Fe/N/C catalysts,synthesized through the pyrolysis of Fe-doped metal–organic framework (MOF) precursors,have attracted extensive attention owing to their promising oxygen reduction reaction (ORR) catalytic activity i...Fe/N/C catalysts,synthesized through the pyrolysis of Fe-doped metal–organic framework (MOF) precursors,have attracted extensive attention owing to their promising oxygen reduction reaction (ORR) catalytic activity in fuel cells and/or metal-air batteries.However,post-treatments (acid washing,second pyrolysis,and so on) are unavoidable to improve ORR catalytic activity and stability.The method for introducing Fe^(3+) sources (anhydrous Fe Cl_(3)) into the MOF structure,in particular,is a critical step that can avoid time-consuming post-treatments and result in more exposed Fe-N_(x) active sites.Herein,three different Fe doping strategies were systematically investigated to explore their influence on the types of active sites formed and ORR performance.Fe-NC(Zn^(2+)),synthesized by one-step pyrolysis of Fe doped ZIF-8 (Zn^(2+)) precursor which was obtained by adding the anhydrous Fe Cl_(3)source into the Zn(NO_(3))_(2)·6H_(2)O/methanol solution before mixing,possessed the highest Fe-N_(x)active sites due to the high-efficiency substitution of Zn^(2+)ions with Fe^(3+) ions during ZIF-8 growth,the strong interaction between Fe^(3+) ions and N atoms of 2-Methylimidazole (2-MIm),and ZIF-8’s micropore confinement effect.As a result,Fe-NC(Zn^(2+)) presented high ORR activity in the entire p H range (p H=1,7,and 13).At p H=13,Fe-NC(Zn^(2+)) exhibited a half-wave potential (E1/2) of 0.95 V (vs.reversible hydrogen electrode),which was 70 m V higher than that of commercial Pt/C.More importantly,Fe-NC(Zn^(2+)) showed superior ORR stability in neutral media without performance loss after 5,000 cycles.A record-high open-circuit voltage(1.9 V) was obtained when Fe-NC(Zn^(2+)) was used as a cathodic catalyst in assembled Mg-air batteries in neutral media.The assembled liquid and all-solid Mg-air batteries with high performance indicated that Fe-NC(Zn^(2+)) has enormous potential for use in flexible and wearable Mg-air batteries.展开更多
High resolution electron energy loss spectroscopy (HREELS) has been used to investigate the adsorption and reaction of CO on the Mo(100)-c(2×2)N surface. CO directly adsorbed on the N atoms from the c(2×2) l...High resolution electron energy loss spectroscopy (HREELS) has been used to investigate the adsorption and reaction of CO on the Mo(100)-c(2×2)N surface. CO directly adsorbed on the N atoms from the c(2×2) layer to form isocyanate (NCO) surface species was found in addition to CO adsorbed on the molybdenum atoms at 120 K. indicating that both Mo and N atoms of the Mo(100)-c(2×2)-N surface are of high reactivities for CO adsorption.展开更多
Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki r...Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki reaction.The structures of the new compounds synthesized were confirmed by elemental analysis,IR,1H NMR and MS.This new method makes a feature of low cost and readily available starting material,fewer steps,mild condition,easiness to operate and higher yield.展开更多
基金supported by Shanxi Province Science Foundation for Youths(202203021212300)Taiyuan University of Science and Technology Scientific Research Initial Funding(20212064)Outstanding Doctoral Award Fund in Shanxi Province(20222060).
文摘The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
基金the National Natural Science Foundation of China （no. 20572096） the Zhejiang Provincial Science Foundation （Grant R405066）.
文摘An efficient route to synthesize the heteroaryl-substituted 1,8-naphthyridine derivatives was described. Eight 2-heteroaryl- and 2,7-diheteroaryl-1,8-naphthyridine derivatives were obtained through palladium-catalyzed C-N-coupling reactions of chloronaphthyridines with imidazole, benzimidazole, morpholine, 3,5-dimethylpyrazole, and phthalimide in moderate to good yields.
基金supported by the National Natural Science Foundation of China(NSFC Grant No. 51706168)
文摘The complex reaction system of the coal gasification coupling C1 reaction was analyzed based on the principles of thermodynamics. The results show that an increase in the temperature is beneficial to the generation of hydrocarbons with high carbon-atom contents, in which the alkane yield is higher than the alkene yield. The complex reaction system consisting of C, H20, CO, CO2, H2, C2H4, C3H6 and C4Hs was studied, and the obtained results indicated that when the maximum mole fraction content of C2-C4 olefins was regarded as the optimized objective function, the optimum temperature was approximately 648 K, the pressure was 0.1 MPa, the feed ratio was approximately 0.6, and the maximum mole fraction content of C2-C4 olefins was approximately 28.24%. The thermodynamic simulation and calculation of the complex reaction system can provide a basis for the determination and optimization of actual process conditions and are therefore of great theoretical and practical significance.
文摘The coupled reaction of methyl acetate and n‐hexane was carried out over a HZSM‐5 catalyst.In addition to a thermal coupling effect,systematic variations in the product distribution were also observed in the coupled system.The bezene‐toluene‐xylene(BTX)selectivity was remarkably improved while the H2,CO,and CO2 selectivity decreased.Rapid deactivation of the catalyst was observed,caused by the extremely high reactivity of methyl acetate,which was alleviated after adding n‐hexane.These results indicated that a coupling effect exists in this system.A detailed pathway for the coupled system is suggested based on the analysis of the surface species,carbonaceous species deposited on the catalyst,as well as the product selectivity changes.The good match between the"hydrogen deficiency"of methyl acetate and the"hydrogen richness"of n‐hexane is consistent with the observed coupling effect.
文摘Poly(4-butyltriarylamine)s with t-butyldimethylsilyl terminal protecting group (PBTPA-TBS) with various molecular weights were prepared by C-N coupling polymerization. The resulting precursors were postfunctionalized and subse- quently used as macroinitiators for atom transfer radial polymerization (ATRP) of n-butyl acrylate (n-BA) and ethyl acrylate (EA). Both the polymerization processes were controlled and the polymers were characterized by 1H NMR, gel permeation chromatography (GPC) and thermal properties, which confirmed the successful synthesis of all the poly-mers. The microphase separated behaviors of the poly (4-butyltriarylamine)-block-poly (butyl acrylate) (PBTPA-b-PBA) were examined by AFM in the film showing phase separation structures for all the polymers. The photorefractive property of the composite based on PBTPA-b-PBA block copolymer was evaluated by two-beam coupling experiment. A relative high gain coefficient of 42.7 cm?1 was obtained at the electric field of 31 V/?m.
基金the support from Key R&D Program of Zhejiang(2024SSYS0064)the Fundamental Research Funds for the Central Universities (2022ZFJH04)。
文摘The electrocatalytic nitrate reduction reaction (NO_(3)RR) powered by renewable energy offers a promising approach for simultaneously reutilization of nitrate and synthesizing high-value products.Nevertheless,theoretical understanding of reaction mechanism was relative illusive,which is indispensable to rationally design of efficient catalysts.Besides,tuning the reaction microenvironment along with the scale-up device development is essential to promote the industrial deployment of electrocatalytic nitrate conversion,while relative research was overlooked.In this regard,recent advances in ammonia synthesis are firstly summarized,including the identification of active sites,exploration of the underlying reaction mechanisms,electrolyzer design and technical-economic analysis.Furthermore,electrocatalytic C–N coupling based on NO_(3)RR to produce higher-value products such as urea and amino acids are also reviewed,to extend the application potential and economic feasibility.Finally,we highlight the existing challenges and the demand of future research for NO_(3)RR.This review anticipates to provide insights into synthesis of high-value products via NO_(3)RR,bridging the gap from laboratory research to industrial fabrication.
基金funded by National Natural Science Foundation of China (21975129)Natural Science Foundation of Jiangsu Province (BK20190759)+1 种基金Nanjing Forestry UniversityPostgraduate Research & Practice Innovation Program of Jiangsu Province (SJCX21_0337)。
文摘Developing high efficient Pd-based electrocatalysts for oxygen reduction reaction(ORR) is still challenging for alkaline membrane fuel cell,since the strong oxygen adsorption energy and easy agglomerative intrinsic properties. In order to simultaneously solve these problems, Pd/Co_(3)O_(4)–N–C multidimensional materials with porous structures is designed as the ORR catalysts. In details, the ZIF-67 with polyhedral structure was firstly synthesized and then annealed at high-temperature to prepare the N-doped Co_(3)O_(4)carbon-based material, which was used to homogeneously confine Pd nanoparticles and obtained the Pd/Co_(3)O_(4)–N–C series catalysts. The formation of Co–N and C–N bond could provide efficient active sites for ORR. Simultaneously, the strong electronic interaction in the interface between the Pd and N-doped Co_(3)O_(4)could disperse and avoid the agglomeration of Pd nanoparticles and ensure the exposure of active sites, which is crucial to lower the energy barrier toward ORR and substantially enhance the ORR kinetics. Hence, the Pd/Co_(3)O_(4)–N–C nanocompounds exhibited excellent ORR catalytic performance, ideal Pd mass activity, and durability in 0.1 mol L-1KOH solution compared with Co_(3)O_(4)–N–C and Pd/C. The scalable synthesis method, relatively low cost, and excellent electrochemical ORR performance indicated that the obtained Pd/Co_(3)O_(4)–N–C electrocatalyst had the potential for application on fuel cells.
基金financial support from the National Natural Science Foundation of China(No.51973240)the Fundamental Research Funds for the Central Universities(Grant No.19lgzd19 and 19lgpy117)+1 种基金China Postdoctoral Science Foundation(No.2019M653176)the Guangdong Yang Fan Innovative&Entepreneurial Research Team Program(Grant No.2016YT03C077)。
文摘Herein,we for the first time demonstrate the synthesis of exfoliated C4N nanosheets via a top-down approach and exploit their use as a new class of organic polymeric catalyst for the oxygen reduction reaction(ORR).The obtained C4N nanosheets are semi-conductive with a small band gap of 1.41 eV and contain abundant pyrazine-nitrogen moieties uniformly distributed throughout C4N.Density function theory calculations reveal that the intramolecular charge transfer induced by pyrazine-nitrogen in C4N enables effective charge redistribution to activate the conjugated structure and facilitate the oxygen adsorption,while the exfoliated sheet-like C4N formation renders improved electrochemical active surface area and results in high exposure of active sites.As a result,despite the bulk C4N is not active,the sheet-like C4N yield markedly improved ORR performance,even on a par with the commercial Pt/C catalyst.Our recent findings not only enrich the family members of two-dimensional conjugated polymer nanosheets but also open up new opportunity to explore new metal-free organic polymeric materials for efficient oxygen reduction catalysis and beyond.
基金supported by the National Natural Science Foundation of China(22171266)the FJIRSM&IUE Joint Research Fund(RHZX-2019-002)+2 种基金the STS Project(KFJ-STS-QYZD-2021-09002)the National Key Basic Research Program of China(2017YFA0403402)the Project of the National Natural Science Foundation of China(U1932119)。
文摘Fe/N/C catalysts,synthesized through the pyrolysis of Fe-doped metal–organic framework (MOF) precursors,have attracted extensive attention owing to their promising oxygen reduction reaction (ORR) catalytic activity in fuel cells and/or metal-air batteries.However,post-treatments (acid washing,second pyrolysis,and so on) are unavoidable to improve ORR catalytic activity and stability.The method for introducing Fe^(3+) sources (anhydrous Fe Cl_(3)) into the MOF structure,in particular,is a critical step that can avoid time-consuming post-treatments and result in more exposed Fe-N_(x) active sites.Herein,three different Fe doping strategies were systematically investigated to explore their influence on the types of active sites formed and ORR performance.Fe-NC(Zn^(2+)),synthesized by one-step pyrolysis of Fe doped ZIF-8 (Zn^(2+)) precursor which was obtained by adding the anhydrous Fe Cl_(3)source into the Zn(NO_(3))_(2)·6H_(2)O/methanol solution before mixing,possessed the highest Fe-N_(x)active sites due to the high-efficiency substitution of Zn^(2+)ions with Fe^(3+) ions during ZIF-8 growth,the strong interaction between Fe^(3+) ions and N atoms of 2-Methylimidazole (2-MIm),and ZIF-8’s micropore confinement effect.As a result,Fe-NC(Zn^(2+)) presented high ORR activity in the entire p H range (p H=1,7,and 13).At p H=13,Fe-NC(Zn^(2+)) exhibited a half-wave potential (E1/2) of 0.95 V (vs.reversible hydrogen electrode),which was 70 m V higher than that of commercial Pt/C.More importantly,Fe-NC(Zn^(2+)) showed superior ORR stability in neutral media without performance loss after 5,000 cycles.A record-high open-circuit voltage(1.9 V) was obtained when Fe-NC(Zn^(2+)) was used as a cathodic catalyst in assembled Mg-air batteries in neutral media.The assembled liquid and all-solid Mg-air batteries with high performance indicated that Fe-NC(Zn^(2+)) has enormous potential for use in flexible and wearable Mg-air batteries.
基金the financial support of this work by the National Natural Science Foundation of China!29873048 ,29873042
文摘High resolution electron energy loss spectroscopy (HREELS) has been used to investigate the adsorption and reaction of CO on the Mo(100)-c(2×2)N surface. CO directly adsorbed on the N atoms from the c(2×2) layer to form isocyanate (NCO) surface species was found in addition to CO adsorbed on the molybdenum atoms at 120 K. indicating that both Mo and N atoms of the Mo(100)-c(2×2)-N surface are of high reactivities for CO adsorption.
文摘Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki reaction.The structures of the new compounds synthesized were confirmed by elemental analysis,IR,1H NMR and MS.This new method makes a feature of low cost and readily available starting material,fewer steps,mild condition,easiness to operate and higher yield.
