We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while...We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.展开更多
Aiming at assessing the ecological stress of land urbanization comprehensively,three perspectives are considered and combined,i.e.the amount effect with the proportion of construction lands as the indicator,the intens...Aiming at assessing the ecological stress of land urbanization comprehensively,three perspectives are considered and combined,i.e.the amount effect with the proportion of construction lands as the indicator,the intensity effect per the density of environmental pollutant emissions,and the location effect based on their spatial distribution in the heterogeneous landscape.The quantitative results of Southern Jiangsu case in Eastern China show the single-perspective ecological stress are spatially different;the proportion effect is higher in city propers which are more densely populated and industrialized.However,the intensity effect is more significant for units along the Yangtze river where heavy industries are gathered,while the location effect is higher in“ecologically suitable”regions.As the integration of proportion,intensity,and location effects,the comprehensive stress differs across Southern Jiangsu and are also different with the single-perspective results.Dominant stressors of each unit are spatially distinct,which benefits policymakers in targeting their objectives as per primary influencing factors.It is concluded that the comprehensive assessment could efficiently reveal the spatial differentiation of the ecological effects of land urbanization and also the differentiated role of different factors for each unit.展开更多
基金the National Key Research and Development Program on Nano Science and Technology of the Ministry of Science and Technology of China(No.2016YFA0200602 and No.2018YFA0208702)the National Natural Science Foundation of China(No.21573211 and No.21633007)the Anhui Initiative in Quantum Information Technologies(No.AHY090200)。
文摘We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.
基金The work was sponsored by the National Natural Science Foundation of China(41871209,41701193 and 41401187).
文摘Aiming at assessing the ecological stress of land urbanization comprehensively,three perspectives are considered and combined,i.e.the amount effect with the proportion of construction lands as the indicator,the intensity effect per the density of environmental pollutant emissions,and the location effect based on their spatial distribution in the heterogeneous landscape.The quantitative results of Southern Jiangsu case in Eastern China show the single-perspective ecological stress are spatially different;the proportion effect is higher in city propers which are more densely populated and industrialized.However,the intensity effect is more significant for units along the Yangtze river where heavy industries are gathered,while the location effect is higher in“ecologically suitable”regions.As the integration of proportion,intensity,and location effects,the comprehensive stress differs across Southern Jiangsu and are also different with the single-perspective results.Dominant stressors of each unit are spatially distinct,which benefits policymakers in targeting their objectives as per primary influencing factors.It is concluded that the comprehensive assessment could efficiently reveal the spatial differentiation of the ecological effects of land urbanization and also the differentiated role of different factors for each unit.
