In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiti...In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiting from the molecularly precise backbones,regular and homogeneous porosity,lightelement composition,nitrogen-rich system with unique electronic band structure of two-dimensional(2D)covalent triazine framework(CTF),as well as the huge specific surface area,superior thermal conductivity,excellent carrier mobility and mechanical properties of 2D graphene,CTF/graphene hybrid-based photocatalysts show great application potential in the field of photocatalysis.In this review,the recent development in synthesis of CTF/graphene hybrid-based photocatalysts,and their applications in photocatalytic water splitting for hydrogen production and photocatalytic degradation of pollutants are summarized.Firstly,we briefly describe the molecular structures,physicochemical properties,and synthetic strategies for CTF/graphene hybrid-based photocatalysts including solution mixing method,in-situ polymerization method and sol-gel method.We further assess the impact of different preparation methods on the structure,morphology,and interacting model between CTF and graphene in CTF/graphene hybrids.Following the various preparation process for CTF/graphene hybrid-based photocatalysts,these methods are analyzed and compared regarding their merits and demerits.Secondly,the functions of CTF/graphene hybrid-based photocatalysts obtained from different synthesis approaches that enhance the catalytic activity for photocataLytic hydrogen evolution and photocatalytic degradation of pollutants are discussed from the three aspects of light harvesting,charge separation and transfer,and surface catalysis.Particular focus has been placed on the catalytic mechanisms of CTF/graphene hybridbased photocatalysts for enhanced photocatalytic hydrogen evolution and improved photocatalytic degradation of pollutants.Then the rational manipulation of 展开更多
The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazin...The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.展开更多
The development of efficient photocatalysts for hydrogen production is crucial in sustainable energy research.In this study,we designed and prepared a Covalent Triazine Framework(CTF)-Cu_(2)O@NC composite featuring an...The development of efficient photocatalysts for hydrogen production is crucial in sustainable energy research.In this study,we designed and prepared a Covalent Triazine Framework(CTF)-Cu_(2)O@NC composite featuring an S-scheme heterojunction structure aimed at enhancing the photocatalytic hydrogen production.The light absorption capacity,electron-hole separation efficiency and H_(2)-evolution activity of the composite were significantly enhanced due to the synergistic effects of the nitrogen-doped carbon(NC)layer and the S-scheme heterojunction.Structural and photoelectrochemical characterization of the system reveal that the S-scheme heterojunctions not only enhance the separation efficiency of photogenerated carriers but also maintain the strong redox capabilities to further promote the photocatalytic reactions.Moreover,the NC layer could simultaneously reduce the photocorrosion of Cu_(2)O and promote the electron transfer.Experimental results demonstrate that the CTF-7%Cu_(2)O@NC composite shows outstanding hydrogen-production performance under visible light,achieving 15645μmol∙g^(−1)∙h^(−1),significantly surpassing the photocatalytic activity of pure CTF(2673μmol∙g^(−1)∙h^(−1)).This study introduces a novel approach to the development of efficient and innovative photocatalytic materials,strongly supporting the advancement of sustainable hydrogen energy.展开更多
The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability.In this study,we demonstrate an efficient catalytic syste...The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability.In this study,we demonstrate an efficient catalytic system formed by integrating Co single sites,which act as the active sites,in covalent triazine frameworks(CTFs),which act as the photoabsorber,for the photocatalytic production of syngas from CO2 in aqueous solution.The enhanced light absorption of the CTFs,which contain intramolecular heterojunctions,in conjunction with 0.8 mmol L^‒1 of the Co complex enables excellent syngas production with a yield of 3303μmol g‒1(CO:H2=1.4:1)in 10 h,which is about three times greater than that achieved using CTF without a heterojunction.In the photocatalytic reaction,the coordinated single Co centers accept the photogenerated electrons from the CTF,and serve as active sites for CO2 conversion through an adsorption-activation-reaction mechanism.Theoretical calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation,thus boosting photocatalytic syngas production.This work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.展开更多
文摘In recent years,photocatalysis with efficient,low-cost and stable metal-free catalysts is one of the most promising technologies for non-polluting energy production and resource-economic environment purifying.Benefiting from the molecularly precise backbones,regular and homogeneous porosity,lightelement composition,nitrogen-rich system with unique electronic band structure of two-dimensional(2D)covalent triazine framework(CTF),as well as the huge specific surface area,superior thermal conductivity,excellent carrier mobility and mechanical properties of 2D graphene,CTF/graphene hybrid-based photocatalysts show great application potential in the field of photocatalysis.In this review,the recent development in synthesis of CTF/graphene hybrid-based photocatalysts,and their applications in photocatalytic water splitting for hydrogen production and photocatalytic degradation of pollutants are summarized.Firstly,we briefly describe the molecular structures,physicochemical properties,and synthetic strategies for CTF/graphene hybrid-based photocatalysts including solution mixing method,in-situ polymerization method and sol-gel method.We further assess the impact of different preparation methods on the structure,morphology,and interacting model between CTF and graphene in CTF/graphene hybrids.Following the various preparation process for CTF/graphene hybrid-based photocatalysts,these methods are analyzed and compared regarding their merits and demerits.Secondly,the functions of CTF/graphene hybrid-based photocatalysts obtained from different synthesis approaches that enhance the catalytic activity for photocataLytic hydrogen evolution and photocatalytic degradation of pollutants are discussed from the three aspects of light harvesting,charge separation and transfer,and surface catalysis.Particular focus has been placed on the catalytic mechanisms of CTF/graphene hybridbased photocatalysts for enhanced photocatalytic hydrogen evolution and improved photocatalytic degradation of pollutants.Then the rational manipulation of
基金The National Natural Science Foundation of China(22078349,22005319,52170109)Self-deployment Program from Lanzhou Institute of Chemical Physics(E30159SQ).
文摘The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.
文摘The development of efficient photocatalysts for hydrogen production is crucial in sustainable energy research.In this study,we designed and prepared a Covalent Triazine Framework(CTF)-Cu_(2)O@NC composite featuring an S-scheme heterojunction structure aimed at enhancing the photocatalytic hydrogen production.The light absorption capacity,electron-hole separation efficiency and H_(2)-evolution activity of the composite were significantly enhanced due to the synergistic effects of the nitrogen-doped carbon(NC)layer and the S-scheme heterojunction.Structural and photoelectrochemical characterization of the system reveal that the S-scheme heterojunctions not only enhance the separation efficiency of photogenerated carriers but also maintain the strong redox capabilities to further promote the photocatalytic reactions.Moreover,the NC layer could simultaneously reduce the photocorrosion of Cu_(2)O and promote the electron transfer.Experimental results demonstrate that the CTF-7%Cu_(2)O@NC composite shows outstanding hydrogen-production performance under visible light,achieving 15645μmol∙g^(−1)∙h^(−1),significantly surpassing the photocatalytic activity of pure CTF(2673μmol∙g^(−1)∙h^(−1)).This study introduces a novel approach to the development of efficient and innovative photocatalytic materials,strongly supporting the advancement of sustainable hydrogen energy.
文摘The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability.In this study,we demonstrate an efficient catalytic system formed by integrating Co single sites,which act as the active sites,in covalent triazine frameworks(CTFs),which act as the photoabsorber,for the photocatalytic production of syngas from CO2 in aqueous solution.The enhanced light absorption of the CTFs,which contain intramolecular heterojunctions,in conjunction with 0.8 mmol L^‒1 of the Co complex enables excellent syngas production with a yield of 3303μmol g‒1(CO:H2=1.4:1)in 10 h,which is about three times greater than that achieved using CTF without a heterojunction.In the photocatalytic reaction,the coordinated single Co centers accept the photogenerated electrons from the CTF,and serve as active sites for CO2 conversion through an adsorption-activation-reaction mechanism.Theoretical calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation,thus boosting photocatalytic syngas production.This work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.
