Pt-(Sn,Re)/HZSM5-HMS catalysts were evaluated for n-heptane isomerization at 200–350 ℃.To characterize the catalyst,X-ray diffraction,X-ray fluorescene,Fourier transform infrared spectroscopy,ultraviolet-visible d...Pt-(Sn,Re)/HZSM5-HMS catalysts were evaluated for n-heptane isomerization at 200–350 ℃.To characterize the catalyst,X-ray diffraction,X-ray fluorescene,Fourier transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,temperature-programmed reduction of H2,temperature-programmed desorption of NH3,infrared spectroscopy of adsorbed pyridine,H2 chemisorption,nitrogen adsorption-desorption,scanning electron microscopy and thermogravimetric analysis were performed.Kinetics of n-C7 isomerization were investigated under various hydrogen and n-C7 pressures,and the effects of reaction conditions on catalytic performance were studied.The results showed that bi-and trimetallic catalysts exhibit better performance than monometallic catalysts for this reaction.For example,a maximum i-C7 selectivity( 〉74%) and multibranched isomer selectivity(40%) were observed for Pt-Sn/HZSM5-HMS at 200 ℃.展开更多
An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high r...An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.展开更多
Fast migration and efficient spatial separation of photogenerated charges in photocatalytic materials are indispensable to efficient solar water splitting reactions.Here,we construct a three-phase heterostructure of C...Fast migration and efficient spatial separation of photogenerated charges in photocatalytic materials are indispensable to efficient solar water splitting reactions.Here,we construct a three-phase heterostructure of CdS/PbTiO_(3)/TiO_(2)by selectively depositing CdS and TiO_(2)at oppositely poled crystal facets of PbTiO_(3)using single-domain ferroelectric PbTiO_(3).The heterostructure has matching band edge alignments and strong interfacial connections at different moieties.The heterostructure combines the interfacial electrical and ferroelectric fields because of their peculiar microstructures,which provide a strong driving force throughout the whole bulk to separate photogenerated charges.Almost two orders of magnitude improvement of visible-light-driven photocatalytic H_(2) production has been realized in CdS/PbTiO_(3)/TiO_(2)compared with bare PbTiO_(3)/TiO_(2),showing the efficiency of charge separation in the heterostructure.The idea of combining ferroelectrics with potential light capture semiconductor provides a paradigm to accurately design charge migration pathways,bringing a step closer to efficient solar water splitting.展开更多
Heterogeneous molecular catalysts,such as metal phthalocyanines,are efficient electrocatalysts for CO_(2) reduction reaction(CO_(2)RR).However,the rational design and synthesis of a molecular catalyst-based heterostru...Heterogeneous molecular catalysts,such as metal phthalocyanines,are efficient electrocatalysts for CO_(2) reduction reaction(CO_(2)RR).However,the rational design and synthesis of a molecular catalyst-based heterostructure for CO_(2)RR remains challenging.Herein,we developed a crystalline bimetallic phthalocyanine heterostructure electrocatalyst(CoPc/FePc HS),which achieved an excellent CO_(2)-to-CO conversion efficiency(99%)and outstanding long-term stability after 10 h of electrocatalysis.Density functional theory calculations revealed that the enhancement of CO_(2)RR performance could be attributed to the distinct electron transfer pattern between FePc and CoPc.The heterostructural engineering in molecular catalysts would inspire a unique approach for improving CO_(2)RR performance.展开更多
The BINOL-amino alcohol enantiomeric pair (S)-I and (R)-I are discovered to conduct both enantioselective and diastereose- lective fluorescent discrimination of the four stereoisomers of threonine derivatives. Thi...The BINOL-amino alcohol enantiomeric pair (S)-I and (R)-I are discovered to conduct both enantioselective and diastereose- lective fluorescent discrimination of the four stereoisomers of threonine derivatives. This study utilizes different fluorescence responses of one sensor at two emission wavelengths toward the stereoisomeric substrates which expands the capability of the sensor in chiral recognition. In addition, the sensor pair also allows visual recognition of the N-protected L-allo-threonine and D-allo-threonine by enantioselective precipitation.展开更多
文摘Pt-(Sn,Re)/HZSM5-HMS catalysts were evaluated for n-heptane isomerization at 200–350 ℃.To characterize the catalyst,X-ray diffraction,X-ray fluorescene,Fourier transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,temperature-programmed reduction of H2,temperature-programmed desorption of NH3,infrared spectroscopy of adsorbed pyridine,H2 chemisorption,nitrogen adsorption-desorption,scanning electron microscopy and thermogravimetric analysis were performed.Kinetics of n-C7 isomerization were investigated under various hydrogen and n-C7 pressures,and the effects of reaction conditions on catalytic performance were studied.The results showed that bi-and trimetallic catalysts exhibit better performance than monometallic catalysts for this reaction.For example,a maximum i-C7 selectivity( 〉74%) and multibranched isomer selectivity(40%) were observed for Pt-Sn/HZSM5-HMS at 200 ℃.
文摘An efficient and E-selective monoisomerization of 1-alkenes is developed with a bis(phosphine)-based PCP-type Co complex as the catalyst.The protocol provides an atom-economical approach to trans-2-alkenes with high regio-and stereoselectivity,featuring mild conditions and wide substrate scope.Mechanistic investigation supports a cobalt-hydride pathway involving reversible alkene insertion/β-H elimination,and the step ofβ-H elimination at the allylic position is likely the rate-determining step.
基金the National Key R&D Program of China(2021YFA1500800)the National Natural Science Foundation of China(51825204,52120105003,and 52072379).
文摘Fast migration and efficient spatial separation of photogenerated charges in photocatalytic materials are indispensable to efficient solar water splitting reactions.Here,we construct a three-phase heterostructure of CdS/PbTiO_(3)/TiO_(2)by selectively depositing CdS and TiO_(2)at oppositely poled crystal facets of PbTiO_(3)using single-domain ferroelectric PbTiO_(3).The heterostructure has matching band edge alignments and strong interfacial connections at different moieties.The heterostructure combines the interfacial electrical and ferroelectric fields because of their peculiar microstructures,which provide a strong driving force throughout the whole bulk to separate photogenerated charges.Almost two orders of magnitude improvement of visible-light-driven photocatalytic H_(2) production has been realized in CdS/PbTiO_(3)/TiO_(2)compared with bare PbTiO_(3)/TiO_(2),showing the efficiency of charge separation in the heterostructure.The idea of combining ferroelectrics with potential light capture semiconductor provides a paradigm to accurately design charge migration pathways,bringing a step closer to efficient solar water splitting.
基金supported by the National Natural Science Foundation of China(22071172,91833306,21875158,51633006,and 51733004).
文摘Heterogeneous molecular catalysts,such as metal phthalocyanines,are efficient electrocatalysts for CO_(2) reduction reaction(CO_(2)RR).However,the rational design and synthesis of a molecular catalyst-based heterostructure for CO_(2)RR remains challenging.Herein,we developed a crystalline bimetallic phthalocyanine heterostructure electrocatalyst(CoPc/FePc HS),which achieved an excellent CO_(2)-to-CO conversion efficiency(99%)and outstanding long-term stability after 10 h of electrocatalysis.Density functional theory calculations revealed that the enhancement of CO_(2)RR performance could be attributed to the distinct electron transfer pattern between FePc and CoPc.The heterostructural engineering in molecular catalysts would inspire a unique approach for improving CO_(2)RR performance.
文摘The BINOL-amino alcohol enantiomeric pair (S)-I and (R)-I are discovered to conduct both enantioselective and diastereose- lective fluorescent discrimination of the four stereoisomers of threonine derivatives. This study utilizes different fluorescence responses of one sensor at two emission wavelengths toward the stereoisomeric substrates which expands the capability of the sensor in chiral recognition. In addition, the sensor pair also allows visual recognition of the N-protected L-allo-threonine and D-allo-threonine by enantioselective precipitation.