The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clos...The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.展开更多
Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization effici...Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster(the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2C-1s-1 at 400 ℃ with a superior selectivity toward CO(> 99.5%). This work 2 highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.展开更多
The research results of processes proceeding in supersonic jets of light hydrocarbons, activated by an electron beam are presented. It is shown, that condensation suppressed at activation by electrons in the initial s...The research results of processes proceeding in supersonic jets of light hydrocarbons, activated by an electron beam are presented. It is shown, that condensation suppressed at activation by electrons in the initial stage of condensation. The developed condensation conditions mode leads to increasing of a part of heavy corpuscles in activated stream and not only owing to stimulation of condensation but because of formation of heavy hydrocarbonic molecules.展开更多
A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-...A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-shaped Ln_(6)topology with the approximate diameter and thickness of 1.5 and 0.7 nm,respectively.All of them show high thermal stability.In the aspect of the catalytic capacities for the cycloaddition reactions of CO_(2)and epoxide,the reaction conditions,the substrate scope,and possible catalytic mechanism were investigated.The highest yield for clusters 1-4 is up to 99%at 333 K for 12 h.In particular,cluster 1 can be reused at least three times with no obvious loss of catalytic performance and keep the integrity of the crystal structure.Magnetic investigations reveal that cluster 1 exhibits a relatively large magnetocaloric effect with-ΔS_(m)=41.43 J/(kg·K)(T=3.0 K,7.0 T);while cluster 3 displays slow magnetic relaxation behavior under zero dc field with U_(eff)=0.51 K andτ_(0)=2.54×10^(-5)s.展开更多
Granular information has emerged as a potent tool for data represen-tation and processing across various domains.However,existing time series data granulation techniques often overlook the influence of external factors...Granular information has emerged as a potent tool for data represen-tation and processing across various domains.However,existing time series data granulation techniques often overlook the influence of external factors.In this study,a multisource time series data granularity conversion model is proposed that achieves granularity conversion effectively while maintaining result consis-tency and stability.The model incorporates the impact of external source data using a multivariate linear regression model,and the entropy weighting method is employed to allocate weights andfinalize the granularity conversion.Through experimental analysis using Beijing’s 2022 air quality dataset,our proposed method outperforms traditional information granulation approaches,providing valuable decision-making insights for industrial system optimization and research.展开更多
基金support from the National Key Research and Development Program of China (No.2020YFA0907300)the National Natural Science Foundation of China (No.22077069)+1 种基金the Natural Science Foundation of Tianjin (19JCZDJC33400)the Fundamental Research Funds for the Central Universities,Nankai University (63201111).
文摘The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.
基金the National Natural Science Foundation of China(21872144,21972140 and 91645117)Liaoning Revitalization Talents Program(XLYC1907053)+2 种基金CAS Youth Innovation Promotion Association(2018220)Talents Innovation Project of Dalian City(2017RQ032 and 2016RD04)China Postdoctoral Science Foundation(2019TQ0314,2018M641726 and 2019M661146)。
文摘Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster(the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2C-1s-1 at 400 ℃ with a superior selectivity toward CO(> 99.5%). This work 2 highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.
文摘The research results of processes proceeding in supersonic jets of light hydrocarbons, activated by an electron beam are presented. It is shown, that condensation suppressed at activation by electrons in the initial stage of condensation. The developed condensation conditions mode leads to increasing of a part of heavy corpuscles in activated stream and not only owing to stimulation of condensation but because of formation of heavy hydrocarbonic molecules.
基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2021L404)。
文摘A series of novel hexanuclear lanthanide dusters,namely,[Ln_(6)(HL)_(6)(NO_(3))_(6)]·3CH_(3)CN(Ln=Gd(1),Tb(2),Dy(3)and Er(4))was assembled using a multidentate ligand H3L(trolamine).The clusters 1-4 show a wheel-shaped Ln_(6)topology with the approximate diameter and thickness of 1.5 and 0.7 nm,respectively.All of them show high thermal stability.In the aspect of the catalytic capacities for the cycloaddition reactions of CO_(2)and epoxide,the reaction conditions,the substrate scope,and possible catalytic mechanism were investigated.The highest yield for clusters 1-4 is up to 99%at 333 K for 12 h.In particular,cluster 1 can be reused at least three times with no obvious loss of catalytic performance and keep the integrity of the crystal structure.Magnetic investigations reveal that cluster 1 exhibits a relatively large magnetocaloric effect with-ΔS_(m)=41.43 J/(kg·K)(T=3.0 K,7.0 T);while cluster 3 displays slow magnetic relaxation behavior under zero dc field with U_(eff)=0.51 K andτ_(0)=2.54×10^(-5)s.
基金This work was supported by the National Key R&D Program of China under Grant No.2020YFB1710200.
文摘Granular information has emerged as a potent tool for data represen-tation and processing across various domains.However,existing time series data granulation techniques often overlook the influence of external factors.In this study,a multisource time series data granularity conversion model is proposed that achieves granularity conversion effectively while maintaining result consis-tency and stability.The model incorporates the impact of external source data using a multivariate linear regression model,and the entropy weighting method is employed to allocate weights andfinalize the granularity conversion.Through experimental analysis using Beijing’s 2022 air quality dataset,our proposed method outperforms traditional information granulation approaches,providing valuable decision-making insights for industrial system optimization and research.
