Emerging as lamellar materials,covalent triazine frameworks(CTFs)exhibited great potential for photocatalysis,but their photocatalytic performance is always hindered by the prone recombination of photogenerated carrie...Emerging as lamellar materials,covalent triazine frameworks(CTFs)exhibited great potential for photocatalysis,but their photocatalytic performance is always hindered by the prone recombination of photogenerated carriers.To overcome this obstacle,a 1D/2D step-scheme(S-scheme)heterojunction is constructed for photocatalytic synthesis of H_(2)O_(2).The S-scheme heterojunction fabricated with CTF and ZnO effectively enhances light absorption,redox capabilities,and charge carrier separation and transfer.In particular,the CTF is decorated with benzothiadiazole and triazine groups as dual O2 reduction active centers,boosting photocatalytic H_(2)O_(2) production.The optimal ZC-10 hybrid delivers a maximum H2O2 generation rate of 12000μmol g^(–1) h^(–1),10.3 and 164 times higher than those of zinc oxide nanorods and CTFs,respectively.Moreover,the charge transfer mechanism in the S-scheme heterojunction is well investigated with in situ spectroscopic measurements and theoretical calculations.展开更多
Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))using covalent organic frameworks(COFs)as photocatalysts holds promise for future applications.However,the influence of linkage chemistry on the photoelectroch...Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))using covalent organic frameworks(COFs)as photocatalysts holds promise for future applications.However,the influence of linkage chemistry on the photoelectrochemical properties and photocatalytic performance of COFs remains a significant challenge.Herein,we designed and synthesized a model system with different linkages,including imine-,amine-,azo-linked COFs,then investigated their photocatalytic activity of overall H_(2)O_(2)production.The photocatalytic results revealed varying activities for H_(2)O_(2)synthesis among these COFs,with the azo-linked TTA-Azo-COF(COF synthesized by 4,4’,4’’-(1,3,5-triazine-2,4,6-triyl)-trianiline and terephthalaldehyde)demonstrating the highest overall H2O2 photosynthesis activity of 2516μmol g^(–1)h^(–1)in an O2 atmosphere without any sacrificial agents,which is 6.72 and 2.85 times higher than that of imine-linked TTA-COF and amine-linked TTA-COF-AR,respectively.Furthermore,TTA-Azo-COF maintained a high photosynthesis H2O2 activity of 2116μmol g^(–1)h^(–1)under an air atmosphere,outperforming most COF-based photocatalytic systems under similar reaction conditions.Further characterizations and density functional theory calculations reveal these various linkages in different COFs result in distinct visible-light absorption,charge transfer capacities and formation energy barriers of key intermediates.This work revealed the significant impact of linkages on COFs and provided comprehensive guidance for the rational design of COFs with tailored linkages to fulfill specific requirements for future applications.展开更多
The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven ...H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven conversion of earth-abundant H_(2)O and O_(2)is the most ideal method for producing H_(2)O_(2).Due to poor separation of photogenerated charge carriers in semiconductors,sacrificial reagents such as ethanol are typically added to consume photogenerated holes,but this is not an energy storage process.Therefore,developing efficient photocatalysts for direct H_(2)O_(2)production from H_(2)O and O_(2)without sacrificial agents is crucial for sustainable energy conversion.Organic framework materials,due to their customizable structures,have gained traction in the photosynthesis of H_(2)O_(2)from pure H_(2)O and O_(2).A series of functionalized molecules have been introduced as building blocks into organic frameworks to enhance the H_(2)O_(2)production performance,but their key roles in performance and reaction pathways have not been summarized in detail so far.This review aims to address this gap and elucidate the relationship between the structure and performance of organic framework photocatalysts,providing insights and guidance for the development of efficient photocatalysts.展开更多
文摘Emerging as lamellar materials,covalent triazine frameworks(CTFs)exhibited great potential for photocatalysis,but their photocatalytic performance is always hindered by the prone recombination of photogenerated carriers.To overcome this obstacle,a 1D/2D step-scheme(S-scheme)heterojunction is constructed for photocatalytic synthesis of H_(2)O_(2).The S-scheme heterojunction fabricated with CTF and ZnO effectively enhances light absorption,redox capabilities,and charge carrier separation and transfer.In particular,the CTF is decorated with benzothiadiazole and triazine groups as dual O2 reduction active centers,boosting photocatalytic H_(2)O_(2) production.The optimal ZC-10 hybrid delivers a maximum H2O2 generation rate of 12000μmol g^(–1) h^(–1),10.3 and 164 times higher than those of zinc oxide nanorods and CTFs,respectively.Moreover,the charge transfer mechanism in the S-scheme heterojunction is well investigated with in situ spectroscopic measurements and theoretical calculations.
文摘Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))using covalent organic frameworks(COFs)as photocatalysts holds promise for future applications.However,the influence of linkage chemistry on the photoelectrochemical properties and photocatalytic performance of COFs remains a significant challenge.Herein,we designed and synthesized a model system with different linkages,including imine-,amine-,azo-linked COFs,then investigated their photocatalytic activity of overall H_(2)O_(2)production.The photocatalytic results revealed varying activities for H_(2)O_(2)synthesis among these COFs,with the azo-linked TTA-Azo-COF(COF synthesized by 4,4’,4’’-(1,3,5-triazine-2,4,6-triyl)-trianiline and terephthalaldehyde)demonstrating the highest overall H2O2 photosynthesis activity of 2516μmol g^(–1)h^(–1)in an O2 atmosphere without any sacrificial agents,which is 6.72 and 2.85 times higher than that of imine-linked TTA-COF and amine-linked TTA-COF-AR,respectively.Furthermore,TTA-Azo-COF maintained a high photosynthesis H2O2 activity of 2116μmol g^(–1)h^(–1)under an air atmosphere,outperforming most COF-based photocatalytic systems under similar reaction conditions.Further characterizations and density functional theory calculations reveal these various linkages in different COFs result in distinct visible-light absorption,charge transfer capacities and formation energy barriers of key intermediates.This work revealed the significant impact of linkages on COFs and provided comprehensive guidance for the rational design of COFs with tailored linkages to fulfill specific requirements for future applications.
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
文摘H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven conversion of earth-abundant H_(2)O and O_(2)is the most ideal method for producing H_(2)O_(2).Due to poor separation of photogenerated charge carriers in semiconductors,sacrificial reagents such as ethanol are typically added to consume photogenerated holes,but this is not an energy storage process.Therefore,developing efficient photocatalysts for direct H_(2)O_(2)production from H_(2)O and O_(2)without sacrificial agents is crucial for sustainable energy conversion.Organic framework materials,due to their customizable structures,have gained traction in the photosynthesis of H_(2)O_(2)from pure H_(2)O and O_(2).A series of functionalized molecules have been introduced as building blocks into organic frameworks to enhance the H_(2)O_(2)production performance,but their key roles in performance and reaction pathways have not been summarized in detail so far.This review aims to address this gap and elucidate the relationship between the structure and performance of organic framework photocatalysts,providing insights and guidance for the development of efficient photocatalysts.
