Porous polymer(pyrrolopyrrole)was successfully prepared via domino-ring-formation reaction.The chemical-physical properties of cyanided covalent triazine frameworks(CTF-CN)were characteriazed by fourier transform infr...Porous polymer(pyrrolopyrrole)was successfully prepared via domino-ring-formation reaction.The chemical-physical properties of cyanided covalent triazine frameworks(CTF-CN)were characteriazed by fourier transform infrared spectra(FT-IR),scanning electron microscopy(SEM),nuclear magnetic resonance(NMR),specific surface area analyzer(BET)and thermogravimetric analysis(TGA),respectively.The experimental results of adsorption of chloranil(TCBQ)in aqueous solution indicated that CTF-CN exhibited distinctive adsorption capacity toward TCBQ owing to its large specific surface area.Specifically,the adsorption equilibrium of as-prepared polymer was executed within 5 h and the calculated adsorption capacity was 499.76 mg/g.Furthermore,the adsorption kinetics could be well defined with the linear pseudo-second-order model,which implies that the chemical interaction are relative important in the course of TCBQ removal.Finally,the current studies verify that CTF-CN has unique rigid and nano-porous framework structure,which can be employed for the treatment of a series of harmful aromatic substances.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
Covalent triazine frameworks(CTFs)are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures,rich porosity,good stability and excellent semiconductivity,w...Covalent triazine frameworks(CTFs)are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures,rich porosity,good stability and excellent semiconductivity,which enable great various applications in efficient gas/molecular adsorption and separation,energy storage and conversion,especially photo-and electrocatalysis.Different synthesis strategies strongly affect the morphology of CTFs and play an important role in their structure and properties.In this concept,we provide a comprehensive and systematic review of the synthesis methods such as ionothermal synthesis,phosphorus pentoxide catalytic method,polycondensation and ultra-strong acid catalyzed method,and applications of CTFs in photo-and electro-catalysis.Finally we offer some insights into the future development progress of CTFs materials for catalytic applications.展开更多
Crystallization is an unsolved challenge in the chemistry of covalent triazine frameworks(CTFs) due to the poorly controlled simultaneous polymerization and crystallization processes. Herein, the synthesis of crystall...Crystallization is an unsolved challenge in the chemistry of covalent triazine frameworks(CTFs) due to the poorly controlled simultaneous polymerization and crystallization processes. Herein, the synthesis of crystalline CTFs via the introduction of aliphatic amine as a dynamic modulator is reported. By optimizing the amount of aliphatic amine, the crystallization process can be controlled in an open system, resulting in the synthesis of crystalline CTFs. These crystalline CTFs exhibit much better photocatalytic hydrogen evolution performance, with highly ordered CTF-1-C3 demonstrating superior performance(10 mmol g^(-1)h^(-1)) compared with most reported CTF-1. This approach also allows for the preparation of various crystalline CTFs.展开更多
A highly conjugated network of covalent triazine frameworks(CTFs)on the one hand promotes light-harvesting,but on the other hand,also results in high carrier recombination which eventually limits their photocatalytic ...A highly conjugated network of covalent triazine frameworks(CTFs)on the one hand promotes light-harvesting,but on the other hand,also results in high carrier recombination which eventually limits their photocatalytic hydrogen evolution reaction(HER)rates.Thus,strategies to favorably tune the electronic configuration of CTFs for efficient photocatalytic HERs need to be developed,but still remain challenging.Herein,a simple in-situ defect strategy involving element doping is developed for the first time to introduce a heteroatom including S and Se into CTF-1 via the condensation of aldehydes with the mixture of the terephthalimidamide and the S-or Se-substituted terephthalimidamide under mild conditions.The doping content(X)is varied,resulting in a series of S-and Se-doped CTFs,named CTFS-1-X and CTFSe-1-X,respectively.Interestingly,for the S-doped CTFs,CTFS-1-10 shows the most excellent HER rate(4,992.3μmol g^(-1)h^(-1))from water splitting,while for the Se-doped ones,CTFSe-1-10 exhibits a photocatalytic HER rate of 5,792.8μmol g^(-1)h^(-1),both of which far surpass undoped CTFs(693.3μmol g^(-1)h^(-1)).In-depth studies indicate that the introduction of S or Se atoms into CTFs could extend the light absorption and promote photo-generated electron-hole pairs migration.Meanwhile,S-or Se-doping could create heterogeneous electronic configuration in CTFs,which can help to suppress carrier recombination.展开更多
Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ord...Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.展开更多
Electroreduction of CO_(2)into chemicals is of great importance in the global carbon balance.Although noble-metal based catalysts and single-atom catalysts(SACs)are known to be active for CO_(2)electroreduction reacti...Electroreduction of CO_(2)into chemicals is of great importance in the global carbon balance.Although noble-metal based catalysts and single-atom catalysts(SACs)are known to be active for CO_(2)electroreduction reaction(CO_(2)RR),the high cost of noble-metal and the lack of effective synthesis approaches to prepare SACs have tremendously hindered the application.Non-metal doped carbon materials have attracted great interest because of their reasonable cost,chemical stability and excellent electrical conductivity.Nevertheless,the design and fabrication of highly efficient non-metal doped carbon electrocatalysts for CO_(2)RR to meet industry demands still remains a big challenge.Herein,triphenylphosphine@covalent triazine frameworks(CTFs)composites were employed as precursors to fabricate N,P dual-doped porous carbon catalysts PCTF-X-Y(X represents the carbonization temperature,and Y represents the mass ratio of CTF to triphenylphosphine)for CO_(2)RR.Due to the high specific surface areas and synergistic effect between N and P,the obtained PCTF-1000-5 exhibited high selectivity for CO production up to 84.3%at–0.7 V versus the reversible hydrogen electrode(vs.RHE)and long-term durability over 16 h,which are better than the reported N,P dual-doped carbon catalysts in aqueous media.This work provides a new way to design and fabricate non-metal catalysts for electrocatalysis.展开更多
Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction(ORR).However,it is still a great challenge to develop a costeffective,ultrastable and efficent single-atom cob...Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction(ORR).However,it is still a great challenge to develop a costeffective,ultrastable and efficent single-atom cobalt catalyst for ORR,requiring efficient fabrication strategies and robust support to stabilize the single cobalt atom.Here,we prepared a highly active and stable atomically isolated cobalt catalyst via covalent triazine framework(CTF)support with Ketjen Black(KB)hybridization in scale.The prepared single Co catalyst(Co-CTF/KB)possesses high metal loading over 4 wt%and shows superior ORR performance with a half-wave potential(E1/2)of 0.830 V and a limiting current density of 6.14 mA cm-2 as well as high tolerance of methanol in an alkaline medium,which outperforms commercial Pt/C and most non-precious-metal catalysts reported to date.Benefiting from strong stabilization of Co atoms on CTF,Co-CTF/KB shows outstanding stability with only 5 mV negative shifts after 10,000 cycles.Moreover,it also displays high catalytic activity for oxygen evolution reaction(OER),suggesting it is an efficient ORR/OER bifunctional catalyst.The present work provides a facile strategy for preparing single-atom catalysts in bulk quantity and contributes to development of catalysts for electrochemical conversion and storage devices.展开更多
Tandem catalytic reactions have attracted extensive interest because of their ability to reduce reaction steps,energy consumption,and waste.However,the construction of highly efficient tandem catalytic systems is stil...Tandem catalytic reactions have attracted extensive interest because of their ability to reduce reaction steps,energy consumption,and waste.However,the construction of highly efficient tandem catalytic systems is still a significant challenge due to the problematic integration of multiple active sites in one reaction system and the incompatibility of different reaction conditions.Although metal nanoparticles(MNPs)supported on porous framework materials have shown excellent catalytic performances in various reactions,their cooperative catalysis for tandem reactions is rarely reported.展开更多
Covalent triazine frameworks(CTFs) as a new type of porous organic polymers(POPs) with nitrogen-rich content, high chemical stability, visible light sensitive, metal-free and fully conjugated structure, have gained co...Covalent triazine frameworks(CTFs) as a new type of porous organic polymers(POPs) with nitrogen-rich content, high chemical stability, visible light sensitive, metal-free and fully conjugated structure, have gained considerable attention in the last ten years owing to their great potential in extensive applications, especially for photocatalysis systems. In this review, we propose to provide current progress in the design and synthesis of CTFs, along with an emphasis on their photocatalytic applications. Firstly, a brief background including the development of photocatalytic areas is provided. Then, synthetic strategies of CTFs are described and compared. Furthermore, the evolution of CTF materials in photocatalysis fields and strategies for enhancing photocatalytic performance is presented. Finally, some perspectives and challenges on synthesizing high crystalline CTFs and designing excellent catalytic performance of CTF materials are discussed, inspiring the development of CTF materials in photocatalytic applications.展开更多
Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation...Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.展开更多
Covalent triazine framework nanosheets (CTF NSs),an emerging class of two-dimensional nanomaterials,have received great attention due to their abundant active sites,permanent porosity,molecular structural diversity,su...Covalent triazine framework nanosheets (CTF NSs),an emerging class of two-dimensional nanomaterials,have received great attention due to their abundant active sites,permanent porosity,molecular structural diversity,superior chemical/thermal stability,and short charge diffusion path,enabling technological breakthroughs in a myriad of applications. The forefront developments and applications of CTF NSs as photocatalysts and electrochemical electrodes have conferred superior performance and made great impact in the field of energy and advanced catalysis. This forward-looking review aims to summarize the research trends,synthesis,properties of CTF NSs and their CTF counterpart,and highlight their progress in applications with respect to energy storage and conversion devices. Finally,the current challenges and future perspectives for CTF NSs are also presented.展开更多
Research on water-splitting electrocatalysts is crucial to establishing a solution to the energy crisis.Herein,we report a facile bottom-up strategy for the preparation of high performance supported electrocatalysts f...Research on water-splitting electrocatalysts is crucial to establishing a solution to the energy crisis.Herein,we report a facile bottom-up strategy for the preparation of high performance supported electrocatalysts for overall water-splitting reaction via a rationally designed defect covalent triazine frameworks(CTFs)support.Specifically,defect CTFs are obtained via binary-precursor polymerization,followed by loading Ru nanoparticles(Ru/D-CTFs-900)with high HER performance at a current density of 10 mA cm-2.The overpotential is only 17 mV.Calcination of the resultant Ru–RuO2/D-CTFs-300 in air,produces excellent OER performance with 190 mV overpotential(at 10 mA cm-2).Furthermore,overall water splitting measurements reveal the potential of 1.47 V,which is better than the majority of the reported Ru-based catalysts.Moreover,density functional theory calculation results show that excellent electrocatalytic properties are attributed to the synergistic effect of Ru nanoparticles and carbon support.展开更多
Porous organic polymers(POPs)are an emerging class of porous materials,having many promising applications in a variety of areas.Among them,covalent triazine frameworks(CTFs)featuring conjugated and porous structures c...Porous organic polymers(POPs)are an emerging class of porous materials,having many promising applications in a variety of areas.Among them,covalent triazine frameworks(CTFs)featuring conjugated and porous structures can be well applied in optoelectronics.To achieve high optoelectronic performance,usually the design and synthesis of CTFs based on appropriate building blocks is critical.Here we report the synthesis of two fluorescent CTFs based on typical fluorescent building blocks,in which CTF-Py constructed from a pyrene(Py)building block was reported for the first time,showing prospective applications in the sensing of nitroaromatics with high sensitivity,and photocatalytic water splitting and carbon dioxide reduction with high performance in comparison with other porous organic materials.展开更多
Photocatalysis using the abundant solar energy is an environmentally friendly and efficient way to degrade organic matter.Covalent triazine frameworks(CTFs),a new class of metal-free organic semiconductors responsive ...Photocatalysis using the abundant solar energy is an environmentally friendly and efficient way to degrade organic matter.Covalent triazine frameworks(CTFs),a new class of metal-free organic semiconductors responsive to visible light,are promising materials for water treatment.In this study,an original CTF,namely CTF-1,was modified by S-doping to form CTFSx,which were used as metal-free catalysts for degradation of methyl orange(MO)and bisphenol A(BPA).The outcomes demonstrated that the photocatalytic degradation of MO and BPA by CTFSxwas superior to that by CTF-1,with better stability and reusability.Within 6 h,53.2%MO and 84.7%BPA were degraded by CTFS5,and the degradation rate constants were 0.145 h-1and 0.29 h-1,respectively,which were 3.6 and 5.8 times higher than those of CTF-1.Further investigation revealed that enhanced visible light absorption,a reduced degree of free carrier recombination,rapid separation and transfer of photogenerated electrons and holes,and improved·OH oxidation capacity were important factors contributing to the significantly enhanced photocatalytic activity.The S-doping method effectively improved the light absorption performance,electronic structure,and modulation band structure of CTF-1.This work highlights the potential application of low-cost metal-free catalysts driven by visible light for the removal of organic pollutants from wastewater.展开更多
Two-dimensional crystalline covalent triazine frameworks(CTFs)have received much attention because oftheir unique triazine structure,which endows CIFs with high thernal and chemical stability,high proportion of nitrog...Two-dimensional crystalline covalent triazine frameworks(CTFs)have received much attention because oftheir unique triazine structure,which endows CIFs with high thernal and chemical stability,high proportion of nitrogen and permanent porosity.Based on this unique structure characteristic.CTFs have shown great potential in energy storage and conversion due to the intrinsically strong conjugated structure.delocalized electron and rich active sites.However.charge carrier(electron,hole or ion)transport can't reach the deep active sites and charge diffusion was impeded by defects in bulk CTFs.Hence,to break through this barrier,increasing attention has been paid to get few lavered CTFs or CTFs nanosheets in order to shorten the pathways of charge diffiusion and expose more active sites.This review summarizes the synthetic methodologies of CTFs nanosheets and the potential application in photocatalvtic and electrochemical energy storage and conversion.展开更多
Electroreduction of CO_(2)(CO_(2) RR)to value-added chemicals offers a promising approach to balance the global carbon emission,but still remains a signifi-cantchallengeduetohighoverpotential,lowfaradaic efficiency,an...Electroreduction of CO_(2)(CO_(2) RR)to value-added chemicals offers a promising approach to balance the global carbon emission,but still remains a signifi-cantchallengeduetohighoverpotential,lowfaradaic efficiency,and poor selectivity of electrocatalysts systems.展开更多
Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and env...Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO_(2) electroreduction reactions(CO_(2)RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.展开更多
Covalent triazine frameworks(CTFs)have been recently employed for visible light-driven photocatalysis due to their unique optical and electronic properties.However,the usually highly hydrophobic nature of CTFs,which o...Covalent triazine frameworks(CTFs)have been recently employed for visible light-driven photocatalysis due to their unique optical and electronic properties.However,the usually highly hydrophobic nature of CTFs,which originates from their overall aromatic backbone,leads to limitations of CTFs for applications in aqueous media.In this study,we aim to extend the range of the application media of CTFs and design hybrid material of a CTF and mesoporous silica(SBA-15)for efficient photocatalysis in aqueous medium.A thiophene-containing CTF was directly synthesized in mesopores of SBA-15.Due to the high surface area and the added hydrophilic properties by silica,the hybrid material demonstrated excellent adsorption of organic molecules in water.This leads not only to high photocatalytic performance of the hybrid material for the degradation of organic dyes in water,but also for efficient photocatalysis in solvent-free and solid state.Furthermore,the reusability,stability and easy recovery of the hybrid material offers promising metal-free heterogeneous photocatalyst for broader applications in different reaction media.展开更多
基金the National Natural Science Foundation of China(Nos.21976069,21677062,21507155)。
文摘Porous polymer(pyrrolopyrrole)was successfully prepared via domino-ring-formation reaction.The chemical-physical properties of cyanided covalent triazine frameworks(CTF-CN)were characteriazed by fourier transform infrared spectra(FT-IR),scanning electron microscopy(SEM),nuclear magnetic resonance(NMR),specific surface area analyzer(BET)and thermogravimetric analysis(TGA),respectively.The experimental results of adsorption of chloranil(TCBQ)in aqueous solution indicated that CTF-CN exhibited distinctive adsorption capacity toward TCBQ owing to its large specific surface area.Specifically,the adsorption equilibrium of as-prepared polymer was executed within 5 h and the calculated adsorption capacity was 499.76 mg/g.Furthermore,the adsorption kinetics could be well defined with the linear pseudo-second-order model,which implies that the chemical interaction are relative important in the course of TCBQ removal.Finally,the current studies verify that CTF-CN has unique rigid and nano-porous framework structure,which can be employed for the treatment of a series of harmful aromatic substances.
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.
基金the National Natural Science Foundation of China(Nos.42167068 and 22269020)Gansu Province Higher Education Industry Support Plan Project(No.2023CYZC-68)the Hubei Province Outstanding Youth Fund Project(No.2023AFA108).
文摘Covalent triazine frameworks(CTFs)are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures,rich porosity,good stability and excellent semiconductivity,which enable great various applications in efficient gas/molecular adsorption and separation,energy storage and conversion,especially photo-and electrocatalysis.Different synthesis strategies strongly affect the morphology of CTFs and play an important role in their structure and properties.In this concept,we provide a comprehensive and systematic review of the synthesis methods such as ionothermal synthesis,phosphorus pentoxide catalytic method,polycondensation and ultra-strong acid catalyzed method,and applications of CTFs in photo-and electro-catalysis.Finally we offer some insights into the future development progress of CTFs materials for catalytic applications.
基金supported by the National Natural Science Foundation of China (21975086, 52203259)the International S&T Cooperation Program of China (22161142005, 2018YFE0117300)。
文摘Crystallization is an unsolved challenge in the chemistry of covalent triazine frameworks(CTFs) due to the poorly controlled simultaneous polymerization and crystallization processes. Herein, the synthesis of crystalline CTFs via the introduction of aliphatic amine as a dynamic modulator is reported. By optimizing the amount of aliphatic amine, the crystallization process can be controlled in an open system, resulting in the synthesis of crystalline CTFs. These crystalline CTFs exhibit much better photocatalytic hydrogen evolution performance, with highly ordered CTF-1-C3 demonstrating superior performance(10 mmol g^(-1)h^(-1)) compared with most reported CTF-1. This approach also allows for the preparation of various crystalline CTFs.
基金supported by the National Natural Science Foundation of China(22078241)the Fundamental Research Funds for the Central Universitiesthe Haihe Laboratory of Sustainable Chemical Transformations。
文摘A highly conjugated network of covalent triazine frameworks(CTFs)on the one hand promotes light-harvesting,but on the other hand,also results in high carrier recombination which eventually limits their photocatalytic hydrogen evolution reaction(HER)rates.Thus,strategies to favorably tune the electronic configuration of CTFs for efficient photocatalytic HERs need to be developed,but still remain challenging.Herein,a simple in-situ defect strategy involving element doping is developed for the first time to introduce a heteroatom including S and Se into CTF-1 via the condensation of aldehydes with the mixture of the terephthalimidamide and the S-or Se-substituted terephthalimidamide under mild conditions.The doping content(X)is varied,resulting in a series of S-and Se-doped CTFs,named CTFS-1-X and CTFSe-1-X,respectively.Interestingly,for the S-doped CTFs,CTFS-1-10 shows the most excellent HER rate(4,992.3μmol g^(-1)h^(-1))from water splitting,while for the Se-doped ones,CTFSe-1-10 exhibits a photocatalytic HER rate of 5,792.8μmol g^(-1)h^(-1),both of which far surpass undoped CTFs(693.3μmol g^(-1)h^(-1)).In-depth studies indicate that the introduction of S or Se atoms into CTFs could extend the light absorption and promote photo-generated electron-hole pairs migration.Meanwhile,S-or Se-doping could create heterogeneous electronic configuration in CTFs,which can help to suppress carrier recombination.
基金Ministry of Trade,Industry&Energy of Korea,Grant/Award Number:RS‐2022‐00155717National Research Foundation of Korea,Grant/Award Numbers:2020H1D3A1A04081472,2022M3J1A1054323。
文摘Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.
基金the National Key Research and Development Program of China(2018YFA0208600,2018YFA0704502)NSFC(21871263,22071245,22033008)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)the Youth Innovation Promotion Association,CAS(Y201850)。
文摘Electroreduction of CO_(2)into chemicals is of great importance in the global carbon balance.Although noble-metal based catalysts and single-atom catalysts(SACs)are known to be active for CO_(2)electroreduction reaction(CO_(2)RR),the high cost of noble-metal and the lack of effective synthesis approaches to prepare SACs have tremendously hindered the application.Non-metal doped carbon materials have attracted great interest because of their reasonable cost,chemical stability and excellent electrical conductivity.Nevertheless,the design and fabrication of highly efficient non-metal doped carbon electrocatalysts for CO_(2)RR to meet industry demands still remains a big challenge.Herein,triphenylphosphine@covalent triazine frameworks(CTFs)composites were employed as precursors to fabricate N,P dual-doped porous carbon catalysts PCTF-X-Y(X represents the carbonization temperature,and Y represents the mass ratio of CTF to triphenylphosphine)for CO_(2)RR.Due to the high specific surface areas and synergistic effect between N and P,the obtained PCTF-1000-5 exhibited high selectivity for CO production up to 84.3%at–0.7 V versus the reversible hydrogen electrode(vs.RHE)and long-term durability over 16 h,which are better than the reported N,P dual-doped carbon catalysts in aqueous media.This work provides a new way to design and fabricate non-metal catalysts for electrocatalysis.
基金supported by the Ministry of Science and Technology of China (2012CB933403)the National Natural Science Foundation of China (51425302 and 51302045)the Chinese Academy of Sciences
文摘Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction(ORR).However,it is still a great challenge to develop a costeffective,ultrastable and efficent single-atom cobalt catalyst for ORR,requiring efficient fabrication strategies and robust support to stabilize the single cobalt atom.Here,we prepared a highly active and stable atomically isolated cobalt catalyst via covalent triazine framework(CTF)support with Ketjen Black(KB)hybridization in scale.The prepared single Co catalyst(Co-CTF/KB)possesses high metal loading over 4 wt%and shows superior ORR performance with a half-wave potential(E1/2)of 0.830 V and a limiting current density of 6.14 mA cm-2 as well as high tolerance of methanol in an alkaline medium,which outperforms commercial Pt/C and most non-precious-metal catalysts reported to date.Benefiting from strong stabilization of Co atoms on CTF,Co-CTF/KB shows outstanding stability with only 5 mV negative shifts after 10,000 cycles.Moreover,it also displays high catalytic activity for oxygen evolution reaction(OER),suggesting it is an efficient ORR/OER bifunctional catalyst.The present work provides a facile strategy for preparing single-atom catalysts in bulk quantity and contributes to development of catalysts for electrochemical conversion and storage devices.
基金support from the National Key Research and Development Program of China(nos.2018YFA0208600 and 2018YFA0704502)NSFC(nos.22071245,21671188,21871263,and 21520102001)+2 种基金Key Research Program of Frontier Science,CAS(no.QYZDJ-SSW-SLH045)Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB20000000)and Youth Innovation Promotion Association,CAS(no.Y201850).
文摘Tandem catalytic reactions have attracted extensive interest because of their ability to reduce reaction steps,energy consumption,and waste.However,the construction of highly efficient tandem catalytic systems is still a significant challenge due to the problematic integration of multiple active sites in one reaction system and the incompatibility of different reaction conditions.Although metal nanoparticles(MNPs)supported on porous framework materials have shown excellent catalytic performances in various reactions,their cooperative catalysis for tandem reactions is rarely reported.
基金supported by the National Natural Science Foundation of China (Nos.22161142005,21975086).
文摘Covalent triazine frameworks(CTFs) as a new type of porous organic polymers(POPs) with nitrogen-rich content, high chemical stability, visible light sensitive, metal-free and fully conjugated structure, have gained considerable attention in the last ten years owing to their great potential in extensive applications, especially for photocatalysis systems. In this review, we propose to provide current progress in the design and synthesis of CTFs, along with an emphasis on their photocatalytic applications. Firstly, a brief background including the development of photocatalytic areas is provided. Then, synthetic strategies of CTFs are described and compared. Furthermore, the evolution of CTF materials in photocatalysis fields and strategies for enhancing photocatalytic performance is presented. Finally, some perspectives and challenges on synthesizing high crystalline CTFs and designing excellent catalytic performance of CTF materials are discussed, inspiring the development of CTF materials in photocatalytic applications.
文摘Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.
文摘Covalent triazine framework nanosheets (CTF NSs),an emerging class of two-dimensional nanomaterials,have received great attention due to their abundant active sites,permanent porosity,molecular structural diversity,superior chemical/thermal stability,and short charge diffusion path,enabling technological breakthroughs in a myriad of applications. The forefront developments and applications of CTF NSs as photocatalysts and electrochemical electrodes have conferred superior performance and made great impact in the field of energy and advanced catalysis. This forward-looking review aims to summarize the research trends,synthesis,properties of CTF NSs and their CTF counterpart,and highlight their progress in applications with respect to energy storage and conversion devices. Finally,the current challenges and future perspectives for CTF NSs are also presented.
基金National Natural Science Foundation of China(Grant nos.21671172,21625604,21706229,21776251)Zhejiang Provincial Natural Science Foundation of China(Grant no.LR19B010001)open fund of State Key Laboratory of Structural Chemistry(No.20170036)。
文摘Research on water-splitting electrocatalysts is crucial to establishing a solution to the energy crisis.Herein,we report a facile bottom-up strategy for the preparation of high performance supported electrocatalysts for overall water-splitting reaction via a rationally designed defect covalent triazine frameworks(CTFs)support.Specifically,defect CTFs are obtained via binary-precursor polymerization,followed by loading Ru nanoparticles(Ru/D-CTFs-900)with high HER performance at a current density of 10 mA cm-2.The overpotential is only 17 mV.Calcination of the resultant Ru–RuO2/D-CTFs-300 in air,produces excellent OER performance with 190 mV overpotential(at 10 mA cm-2).Furthermore,overall water splitting measurements reveal the potential of 1.47 V,which is better than the majority of the reported Ru-based catalysts.Moreover,density functional theory calculation results show that excellent electrocatalytic properties are attributed to the synergistic effect of Ru nanoparticles and carbon support.
基金supported by the National Natural Science Foundation of China(21875078 and 21975146)。
文摘Porous organic polymers(POPs)are an emerging class of porous materials,having many promising applications in a variety of areas.Among them,covalent triazine frameworks(CTFs)featuring conjugated and porous structures can be well applied in optoelectronics.To achieve high optoelectronic performance,usually the design and synthesis of CTFs based on appropriate building blocks is critical.Here we report the synthesis of two fluorescent CTFs based on typical fluorescent building blocks,in which CTF-Py constructed from a pyrene(Py)building block was reported for the first time,showing prospective applications in the sensing of nitroaromatics with high sensitivity,and photocatalytic water splitting and carbon dioxide reduction with high performance in comparison with other porous organic materials.
基金supported by the National Natural Science Foundation of China(Nos.22006131 and 22276171)the Zhejiang Provincial Natural Science Foundation of China(No.LQ20B070010)+1 种基金the China Postdoctoral Science Foundation(Nos.2020T130598 and 2019M662106)the Fund of Zhuhai Science and Technology Bureau,China(No.ZH22017003210025PWC)。
文摘Photocatalysis using the abundant solar energy is an environmentally friendly and efficient way to degrade organic matter.Covalent triazine frameworks(CTFs),a new class of metal-free organic semiconductors responsive to visible light,are promising materials for water treatment.In this study,an original CTF,namely CTF-1,was modified by S-doping to form CTFSx,which were used as metal-free catalysts for degradation of methyl orange(MO)and bisphenol A(BPA).The outcomes demonstrated that the photocatalytic degradation of MO and BPA by CTFSxwas superior to that by CTF-1,with better stability and reusability.Within 6 h,53.2%MO and 84.7%BPA were degraded by CTFS5,and the degradation rate constants were 0.145 h-1and 0.29 h-1,respectively,which were 3.6 and 5.8 times higher than those of CTF-1.Further investigation revealed that enhanced visible light absorption,a reduced degree of free carrier recombination,rapid separation and transfer of photogenerated electrons and holes,and improved·OH oxidation capacity were important factors contributing to the significantly enhanced photocatalytic activity.The S-doping method effectively improved the light absorption performance,electronic structure,and modulation band structure of CTF-1.This work highlights the potential application of low-cost metal-free catalysts driven by visible light for the removal of organic pollutants from wastewater.
基金Supported by the National Natural Science Foundation of China(Nos 51873039,51673042)the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(CAST)(No.2017QNRCO01).
文摘Two-dimensional crystalline covalent triazine frameworks(CTFs)have received much attention because oftheir unique triazine structure,which endows CIFs with high thernal and chemical stability,high proportion of nitrogen and permanent porosity.Based on this unique structure characteristic.CTFs have shown great potential in energy storage and conversion due to the intrinsically strong conjugated structure.delocalized electron and rich active sites.However.charge carrier(electron,hole or ion)transport can't reach the deep active sites and charge diffusion was impeded by defects in bulk CTFs.Hence,to break through this barrier,increasing attention has been paid to get few lavered CTFs or CTFs nanosheets in order to shorten the pathways of charge diffiusion and expose more active sites.This review summarizes the synthetic methodologies of CTFs nanosheets and the potential application in photocatalvtic and electrochemical energy storage and conversion.
基金We acknowledge the financial support received from the National Key Research and Development Program of China(2018YFA0208600 and 2017YFA0700100)Key Research Program of Frontier Science,CAS(QYZDJ-SSW-SLH045)+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)NSFC(21671188,21871263 and 21520102001)Youth Innovation Promotion Association,CAS(2014265).
文摘Electroreduction of CO_(2)(CO_(2) RR)to value-added chemicals offers a promising approach to balance the global carbon emission,but still remains a signifi-cantchallengeduetohighoverpotential,lowfaradaic efficiency,and poor selectivity of electrocatalysts systems.
基金This work was supported by the National Key Research and Development Program of China(Nos.2018YFA0208600,2018YFA0704502)the National Natural Science Foundation of China(Nos.21871263,22071245,22033008)+1 种基金the Fund of the Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103)the Project of the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y201850).
文摘Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO_(2) electroreduction reactions(CO_(2)RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.
基金K.A.I.Z.acknowledges the Max Planck Society for financial support.C.A.is a recipient of a fellowship through funding of the Excellence Initiative(DFG/GSC 266)of the Graduate School of Excellence“MAINZ”(Materials Science in Mainz).
文摘Covalent triazine frameworks(CTFs)have been recently employed for visible light-driven photocatalysis due to their unique optical and electronic properties.However,the usually highly hydrophobic nature of CTFs,which originates from their overall aromatic backbone,leads to limitations of CTFs for applications in aqueous media.In this study,we aim to extend the range of the application media of CTFs and design hybrid material of a CTF and mesoporous silica(SBA-15)for efficient photocatalysis in aqueous medium.A thiophene-containing CTF was directly synthesized in mesopores of SBA-15.Due to the high surface area and the added hydrophilic properties by silica,the hybrid material demonstrated excellent adsorption of organic molecules in water.This leads not only to high photocatalytic performance of the hybrid material for the degradation of organic dyes in water,but also for efficient photocatalysis in solvent-free and solid state.Furthermore,the reusability,stability and easy recovery of the hybrid material offers promising metal-free heterogeneous photocatalyst for broader applications in different reaction media.
基金financially supported by the National Natural Science Foundation of China(22161142005,21975086)the Science and Technology Department of Hubei Province(2019CFA008)。
