Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channe...Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channel.Herein,we present a Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)Z-scheme heterojunction prepared with an in-situ growth method based on the Sb atomic pinning effect.As revealed by the analysis of experimental and theoretical calculation results,the introduction of Sb anchors on C_(3)N_(4)leads to the formation of an Sb–N charge transfer bridge between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4),promoting interfacial charge communication over Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)heterojunction.Moreover,it can induce the heterojunction interfacial charge transfer pathway between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4)to change from type II to the type Z-scheme,enabling the change of the catalytic site from C_(3)N_(4)to Cs_(3)Sb_(2)Br_(9),thus promoting the CO_(2)activation.As a result,Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)achieves efficient CO_(2)to CO photocatalytic conversion using water as the electron source under simulated solar light irradiation(100 mW·cm^(−2)),with the yield of 198.4μmol·g^(−1)·h^(−1),which is nearly 3-fold and 9-fold over the counterpart synthesized catalyst without Sb anchors(Cs_(3)Sb_(2)Br_(9)/g–C_(3)N_(4))and pure g–C_(3)N_(4),respectively.This work provides a new alternative solution for the design of highly efficient heterojunction photocatalysts.展开更多
Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative p...Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative photoredox and chiral hydrogenbonding catalysis to effectively address this challenge,as a variety of products are obtained in high yields(up to 85%)with good to excellent enantioselectivities(up to 98%ee).The formation of thermodynamically favorable enol intermediates after double single-electron reduction represents the center of the success.Additionally,the utility of the current method is validated by the convenient regio-specific and-diverse synthesis of various deuterated derivatives for these products using inexpensive D_(2)O as the deuterium source.展开更多
针对适用于焦化烟气的溴掺杂钒钛催化剂,为进一步探索其脱硝机理及动力学规律,研究采用浸渍法制备V/Br-Ti催化剂,从瞬态动力学和稳态动力学的角度对催化剂进行反应动力学研究。结果表明,在250℃时4V5Br-Ti催化剂的脱硝效率达到98%;在V/B...针对适用于焦化烟气的溴掺杂钒钛催化剂,为进一步探索其脱硝机理及动力学规律,研究采用浸渍法制备V/Br-Ti催化剂,从瞬态动力学和稳态动力学的角度对催化剂进行反应动力学研究。结果表明,在250℃时4V5Br-Ti催化剂的脱硝效率达到98%;在V/Br-Ti催化剂上进行的SCR反应机制是吸附态的NH_3与气态或弱吸附态的NO发生反应;O_2是以气态氧、表面吸附氧和晶格氧三种形态参与SCR反应的。在实验条件下,V/Br-Ti催化剂的NH_3、O_2、NO反应级数分别为0、0.5、1级。4V5Br-Ti催化剂SCR表观反应活化能为35.4 k J×mol^(-1),低于目前商用的钒钛基脱硝催化剂,表明该催化剂具有较高的反应活性,具有一定的实际工业应用潜力。展开更多
基金financially supported by the National Key R&D Program of China(2022YFA1502902)the National Natural Science Foundation of China(U21A20286 and 22305214)+2 种基金the Natural Science Foundation of Tianjin City(17JCJQJC43800)the 111 Project of Chinathe Jiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB616)。
文摘Developing highly efficient heterostructural photocatalysts for direct CO_(2)reduction coupled with water oxidation remains challenging,the key to which is to establish an efficient interfacial charge transport channel.Herein,we present a Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)Z-scheme heterojunction prepared with an in-situ growth method based on the Sb atomic pinning effect.As revealed by the analysis of experimental and theoretical calculation results,the introduction of Sb anchors on C_(3)N_(4)leads to the formation of an Sb–N charge transfer bridge between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4),promoting interfacial charge communication over Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)heterojunction.Moreover,it can induce the heterojunction interfacial charge transfer pathway between Cs_(3)Sb_(2)Br_(9)and C_(3)N_(4)to change from type II to the type Z-scheme,enabling the change of the catalytic site from C_(3)N_(4)to Cs_(3)Sb_(2)Br_(9),thus promoting the CO_(2)activation.As a result,Cs_(3)Sb_(2)Br_(9)/Sb–C_(3)N_(4)achieves efficient CO_(2)to CO photocatalytic conversion using water as the electron source under simulated solar light irradiation(100 mW·cm^(−2)),with the yield of 198.4μmol·g^(−1)·h^(−1),which is nearly 3-fold and 9-fold over the counterpart synthesized catalyst without Sb anchors(Cs_(3)Sb_(2)Br_(9)/g–C_(3)N_(4))and pure g–C_(3)N_(4),respectively.This work provides a new alternative solution for the design of highly efficient heterojunction photocatalysts.
基金supported by the National Natural Science Foundation of China(22171072,21925103,22301061)Henan Normal University。
文摘Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative photoredox and chiral hydrogenbonding catalysis to effectively address this challenge,as a variety of products are obtained in high yields(up to 85%)with good to excellent enantioselectivities(up to 98%ee).The formation of thermodynamically favorable enol intermediates after double single-electron reduction represents the center of the success.Additionally,the utility of the current method is validated by the convenient regio-specific and-diverse synthesis of various deuterated derivatives for these products using inexpensive D_(2)O as the deuterium source.
基金financially supported by the Key Science & Technology Specific Projects of Yangzhou, Jiangsu Province of China (YZ2010024)the Key Science & Technology Specific Projects of Guangxi Province of China (11107021-3-1)+1 种基金the Scientific Research Project of Guangxi Education Department (201010LX186)the Doctoral Foundation of Guilin University of Technology (002401003321)~~
文摘针对适用于焦化烟气的溴掺杂钒钛催化剂,为进一步探索其脱硝机理及动力学规律,研究采用浸渍法制备V/Br-Ti催化剂,从瞬态动力学和稳态动力学的角度对催化剂进行反应动力学研究。结果表明,在250℃时4V5Br-Ti催化剂的脱硝效率达到98%;在V/Br-Ti催化剂上进行的SCR反应机制是吸附态的NH_3与气态或弱吸附态的NO发生反应;O_2是以气态氧、表面吸附氧和晶格氧三种形态参与SCR反应的。在实验条件下,V/Br-Ti催化剂的NH_3、O_2、NO反应级数分别为0、0.5、1级。4V5Br-Ti催化剂SCR表观反应活化能为35.4 k J×mol^(-1),低于目前商用的钒钛基脱硝催化剂,表明该催化剂具有较高的反应活性,具有一定的实际工业应用潜力。
