Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has...Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.展开更多
A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potenti...A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.展开更多
Electrochemical CO_(2)reduction to value-added fuels and chemicals is recognized as a promising strategy to alleviate energy shortages and global warming owing to its high efficiency and economic feasibility.Recently,...Electrochemical CO_(2)reduction to value-added fuels and chemicals is recognized as a promising strategy to alleviate energy shortages and global warming owing to its high efficiency and economic feasibility.Recently,understanding the activity origin,selectivity regulation,and reaction mechanisms of CO_(2)reduction reactions(CO_(2)RRs)has become the focus of efficient electrocatalyst design.Polyoxometalates(POMs),a unique class of nanosized metal-oxo clusters,are promising candidates for the development of efficient CO_(2)RR electrocatalysts and,owing to their well-defined structure,remarkable electron/proton storage and transfer ability,and capacities for adsorption and activation of CO_(2),are ideal models for investigating the activity origin and reaction mechanisms of CO_(2)RR electrocatalysts.In this review,we focus on the activity origin and mechanism of CO_(2)RRs and survey recent advances that were achieved by employing POMs in electrocatalytic CO_(2)RRs.We highlight the significant roles of POMs in the electrocatalytic CO_(2)RR process and the main factors influencing selectivity regulation and catalytic CO_(2)RR performance,including the electrolyte,electron-transfer process,and surface characteristics.Finally,we offer a perspective of the advantages and future challenges of POM-based materials in electrocatalytic CO_(2)reduction that could inform new advancements in this promising research field.展开更多
In the present review, we summarize the progress for thermal reductive transformations of CO2 catalyzed by small homogeneous catalysts using earth-abundant elements. Three main types of transformations categorized by ...In the present review, we summarize the progress for thermal reductive transformations of CO2 catalyzed by small homogeneous catalysts using earth-abundant elements. Three main types of transformations categorized by the use of different reductants(hydrogen, hydrosilanes, and boranes), in which no C–C bond formation is involved, are surveyed.展开更多
文摘Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.
基金This work is supported by the National Natural Science Foundation of China （No.51372248, No.51432009 and No.51502297）, Instrument Developing Project of the Chinese Academy of Sciences （No.yz201421）, the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, China.
文摘A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.
文摘Electrochemical CO_(2)reduction to value-added fuels and chemicals is recognized as a promising strategy to alleviate energy shortages and global warming owing to its high efficiency and economic feasibility.Recently,understanding the activity origin,selectivity regulation,and reaction mechanisms of CO_(2)reduction reactions(CO_(2)RRs)has become the focus of efficient electrocatalyst design.Polyoxometalates(POMs),a unique class of nanosized metal-oxo clusters,are promising candidates for the development of efficient CO_(2)RR electrocatalysts and,owing to their well-defined structure,remarkable electron/proton storage and transfer ability,and capacities for adsorption and activation of CO_(2),are ideal models for investigating the activity origin and reaction mechanisms of CO_(2)RR electrocatalysts.In this review,we focus on the activity origin and mechanism of CO_(2)RRs and survey recent advances that were achieved by employing POMs in electrocatalytic CO_(2)RRs.We highlight the significant roles of POMs in the electrocatalytic CO_(2)RR process and the main factors influencing selectivity regulation and catalytic CO_(2)RR performance,including the electrolyte,electron-transfer process,and surface characteristics.Finally,we offer a perspective of the advantages and future challenges of POM-based materials in electrocatalytic CO_(2)reduction that could inform new advancements in this promising research field.
文摘In the present review, we summarize the progress for thermal reductive transformations of CO2 catalyzed by small homogeneous catalysts using earth-abundant elements. Three main types of transformations categorized by the use of different reductants(hydrogen, hydrosilanes, and boranes), in which no C–C bond formation is involved, are surveyed.
