In conjugated polymers(CPs)photocatalytic system,the generation of reactive oxygen species(ROS)is regulated by cross-scale factors involving active site,excitonic behavior,and O_(2)activation process on the surface.Ho...In conjugated polymers(CPs)photocatalytic system,the generation of reactive oxygen species(ROS)is regulated by cross-scale factors involving active site,excitonic behavior,and O_(2)activation process on the surface.However,research on exploring the domino effect of“structure→excitonic behavior→O_(2)activation→photocatalytic reaction”through structural modification at the atomic scale remains at its early stages.Herein,two heptazine-based CPs,CP-DPA,and CP-CZ were successfully prepared by polymerization of precursors formed by reacting diphenylamine(DPA)and carbazole(CZ)with cyameluric chloride,respectively.The minute difference in single bond between DPA and CZ endows the polymers with distinct physicochemical properties.Owing to the rotation between benzene rings,CP-DPA exhibits relatively lower conjugation,resulting in increased exciton binding energy(Eb)and inhibited exciton dissociation.Meanwhile,its more triplet state excitons facilitate energy transfer to generate singlet oxygen.Therefore,CP-DPA shows excellent activity for phenylboronic acid oxidation.Conversely,CP-CZ possesses relatively higher conjugation,minimal Eb and intensified exciton dissociation,which promotes charge transfer to produce superoxide radical.Consequently,CP-CZ displays optimal activity for phe-nylacetylene oxidation and[3+2]cycloaddition.This work provides new insights into regulating ROS gener-ation by modulating the composition and structure of photocatalysts at the atomic scale.展开更多
With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-T...With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-Tianjin-Hebei area,in order to provide reference for Beijing-Tianjin-Hebei joint development. The results show that in terms of industrial structure competitiveness,Beijing > Tianjin > Hebei; in terms of agricultural competitiveness,Tianjin > Beijing > Hebei; in terms of industrial competitiveness,Tianjin > Beijing > Hebei; in terms of service industry competitiveness,Tianjin > Beijing > Hebei; in terms of high-tech industry competitiveness,Beijing > Tianjin > Hebei. It is suggested that Beijing-Tianjin-Hebei should further optimize industrial structure,and develop modern service industry. In the Beijing-TianjinHebei joint development,Hebei should focus on the development of agriculture,Tianjin should focus on the development of industry,and Beijing should focus on the development of high-tech industry.展开更多
基金supported by National Natural Science Foundation of China(22171041,22071020,52130101)National Key R&D Program of China(2023YFB3003001)+2 种基金Natural Science Foundation of Jilin Province Science and Technology Department(discipline layout project)(grant no.20230508094RC)the Fundamental Research Funds for the Central Universities(grant no.2412021QD008)the Fundamental Research Funds for the Central Universities-Excellent Youth Team Program(2412023YQ001).
文摘In conjugated polymers(CPs)photocatalytic system,the generation of reactive oxygen species(ROS)is regulated by cross-scale factors involving active site,excitonic behavior,and O_(2)activation process on the surface.However,research on exploring the domino effect of“structure→excitonic behavior→O_(2)activation→photocatalytic reaction”through structural modification at the atomic scale remains at its early stages.Herein,two heptazine-based CPs,CP-DPA,and CP-CZ were successfully prepared by polymerization of precursors formed by reacting diphenylamine(DPA)and carbazole(CZ)with cyameluric chloride,respectively.The minute difference in single bond between DPA and CZ endows the polymers with distinct physicochemical properties.Owing to the rotation between benzene rings,CP-DPA exhibits relatively lower conjugation,resulting in increased exciton binding energy(Eb)and inhibited exciton dissociation.Meanwhile,its more triplet state excitons facilitate energy transfer to generate singlet oxygen.Therefore,CP-DPA shows excellent activity for phenylboronic acid oxidation.Conversely,CP-CZ possesses relatively higher conjugation,minimal Eb and intensified exciton dissociation,which promotes charge transfer to produce superoxide radical.Consequently,CP-CZ displays optimal activity for phe-nylacetylene oxidation and[3+2]cycloaddition.This work provides new insights into regulating ROS gener-ation by modulating the composition and structure of photocatalysts at the atomic scale.
文摘With the industrial competitiveness in the Beijing-Tianjin-Hebei area in 2013 as the object of study,this paper uses principal component analysis to evaluate and compare the industrial competitiveness in the Beijing-Tianjin-Hebei area,in order to provide reference for Beijing-Tianjin-Hebei joint development. The results show that in terms of industrial structure competitiveness,Beijing > Tianjin > Hebei; in terms of agricultural competitiveness,Tianjin > Beijing > Hebei; in terms of industrial competitiveness,Tianjin > Beijing > Hebei; in terms of service industry competitiveness,Tianjin > Beijing > Hebei; in terms of high-tech industry competitiveness,Beijing > Tianjin > Hebei. It is suggested that Beijing-Tianjin-Hebei should further optimize industrial structure,and develop modern service industry. In the Beijing-TianjinHebei joint development,Hebei should focus on the development of agriculture,Tianjin should focus on the development of industry,and Beijing should focus on the development of high-tech industry.
