An efficient acetic acid mediated metal-free oxidative C—H cross coupling of imidazo[1,2-a]pyridines with glyoxal hydrates has been developed under air atmosphere.The present protocol exhibits broad substrate scope,g...An efficient acetic acid mediated metal-free oxidative C—H cross coupling of imidazo[1,2-a]pyridines with glyoxal hydrates has been developed under air atmosphere.The present protocol exhibits broad substrate scope,good functional group tolerance,and enables the construction of a series of 1,2-dicarbonyl imidazo[1,2-a]pyridines in good yields.The reaction mechanism studies suggest that the reactions proceed through the electrophilic substitution and subsequent oxidation pathway.展开更多
Metal-free carbon catalysts have garnered significant attention since their inception.Despite substantial advancements,including widely adopted strategies such as heteroatom doping and defect engineering,their catalyt...Metal-free carbon catalysts have garnered significant attention since their inception.Despite substantial advancements,including widely adopted strategies such as heteroatom doping and defect engineering,their catalytic performance remains inferior to that of metal-based catalysts.In this study,we have predicted and demonstrated that the curvature of carbon plays a pivotal role in the adsorption of acetylene and the overall catalytic performance.First-principles calculations suggest that a tip-enhanced local electric field at the defect site on the curved carbon catalyst enhances the reaction kinetics for acetylene hydrochlorination.The experimental results highlight the structural advantages of the curved defect site,revealing that high-curvature defective carbon(HCDC)demonstrates an adsorption capacity for acetylene that is almost two orders of magnitude higher than that of defective carbon.Notably,HCDC achieves an acetylene conversion of up to 90%at 220℃under a gas hourly space velocity of 300 h^(-1),significantly surpassing the performance of the benchmark 0.25%Au/AC catalyst.This proof-of-concept study reveals the fundamental mechanisms driving the superior performance of carbon catalysts with curved nanostructures and presents a straightforward,environmentally friendly method for large-scale production of carbon materials with precisely controlled nanostructures.It highlights the potential for commercializing metal-free carbon catalysts in acetylene hydrochlorination and related heterogenous catalytic reactions.展开更多
The development of high-voltage tandem thin-film supercapacitors(TFSCs)has been limited by the issues such as expensive electrode materials,indispensable commercial separators and metal current collectors,and complex ...The development of high-voltage tandem thin-film supercapacitors(TFSCs)has been limited by the issues such as expensive electrode materials,indispensable commercial separators and metal current collectors,and complex manufacturing processes.Herein,we develop a potentially scalable approach to address all these issues by using CO_(2) laser pyrolysis of polyimide(PI)paper into the three-dimensional(3D)morphology of graphene paper in air.The formation process and mechanism of PI to graphene were clarified by microstructure and chemical characterizations and reaction molecular dynamics.The influences of laser scan density,power,defocus,and scan speed on the sheet resistance,longitudinal resistance,Raman spectra,and electrochemical performance of graphene papers were systematically investigated.Results indicate that high-quality graphene papers with ultralow sheet resistance(4.88Ω·square^(-1))and longitudinal resistance(3.46Ω)and extra-large crystalline size(96.1 nm)were achieved under optimized process parameters.The graphene papers can simultaneously serve as active electrode materials,current collectors,and interconnectors.The active area of electrodes is defined by a PI mask,with the help of which a hydrogel electrolyte functions as a separator.The assembled graphene paper-based TFSCs demonstrate outstanding electrochemical performance and mechanical flexibility,with the areal capacitance of 54.5 mF·cm^(-2),energy density of 10.9µWh·cm^(-2),and cycle stability retention of 86.9%over 15000 cycles.Moreover,all the tandem metal-free TFSCs,ranging from 1 to 160 cells,show excellent performance uniformity.The output voltage increases linearly from 1.2 V to 200 V.Significantly,the 160-tandem TFSCs exhibit a high voltage density within a compact volume of∼3.8 cm^(3).This work provides an avenue for achieving tandem metal-free TFSCs in a simple and efficient manner.展开更多
We report a general method for the synthesis of polymer-decorated metal-organic frameworks(MOFs)for the fabrication of superhy-drophobic materials through photoinduced metal-free atom transfer radical polymerization(A...We report a general method for the synthesis of polymer-decorated metal-organic frameworks(MOFs)for the fabrication of superhy-drophobic materials through photoinduced metal-free atom transfer radical polymerization(ATRP).Firstly,an MOF material,ZIF-8-NH_(2),was syn-thesized through the self-assembly of metal ions and organic ligands at room temperature.ZIF-8-NH_(2)was then reacted with glycidyl methacry-late(GMA)to form ZIF-8@GMA.Finally,ZIF-8@GMA-PHFBA was prepared by grafting fluorinated monomer 2,2,3,4,4,4-hexafluorobutyl acrylate(HFBA),from the ZIF-8@GMA surface via photoinduced ATRP under 365 nm UV light.The structural evolution during the metal-free ATRP modifi-cation of ZIF-8-NH_(2)was characterized by Fourier transform infrared spectroscopy(FTIR),X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and thermogravimetry analysis(TGA).The test results verified that ZIF-8-NH_(2)and ZIF-8@GMA-PHFBA were successfully synthesized,and that the surface graft polymerization did not change the structure and morphology of ZIF-8-NH_(2).After anchoring the ZIF-8@GMA-PHFBA hybrid material on the fabric surface,the water contact angle(WCA)of the ZIF-8@GMA-PHFBA hy-brid material-modified fabric surface reached 154.2,which achieved a superhydrophobic state.In addition,the oil-water separation experiment and self-cleaning test demonstrated that the ZIF-8@GMA-PHFBA hybrid material-modified fabric has an excellent oil-water separation effect and self-cleaning performance.This material shows promising potential for applications in self-cleaning and oil-water separation technologies.展开更多
The development of metal-free carbon catalysts has garnered significant attention as a promising approach to address the challenges of sustainable catalysis,particularly in the replacement of toxic and environmentally...The development of metal-free carbon catalysts has garnered significant attention as a promising approach to address the challenges of sustainable catalysis,particularly in the replacement of toxic and environmentally hazardous mercury-based systems for the coal-based PVC industry.Within a decade of development,the catalytic performance of carbon catalysts has been improved greatly and even shows superiorities over metal catalysts in some cases,which have demonstrated great potential as sustainable alternatives to mercury catalysts.This review provides a comprehensive summary of the recent advancements in carbon catalysts for acetylene hydrochlorination.It encompasses a wide range of aspects,including the identification of active sites from heteroatom doping to intrinsic carbon defects,the various synthetic strategies employed,the reaction and deactivation mechanisms of carbon catalysts,and the current insights into the key challenges that are encountered on the journey from laboratory research to scalable commercialization within the field of carbon catalysts.The review offers foundational insights and practical guidelines for designing green carbon catalysts systems,not only for acetylene hydrochlorination but also for other heterogeneous catalytic reactions.展开更多
Designing exceptional-performance and long-lasting oxygen reduction reaction(ORR)catalysts is a critical challenge for the development of rechargeable Zn-air batteries(ZABs).In this study,we introduce a metal-free ORR...Designing exceptional-performance and long-lasting oxygen reduction reaction(ORR)catalysts is a critical challenge for the development of rechargeable Zn-air batteries(ZABs).In this study,we introduce a metal-free ORR catalyst composed of F-N co-doped hollow carbon(FNC),specifically engineered to address the limitations of conventional catalysts.The FNC catalysts were synthesized using a template-assisted pyrolysis method,resulting in a hollow,porous architecture with a high specific surface area and numerous active sites.Concurrently,F doping optimized the electronic configuration of pyridinic nitrogen.The introduction of C-F bonds reduced the reaction energy barrier,and the resulting N-C-F configuration enhanced the stability of the nitrogen center.The catalyst exhibits outstanding ORR activity in alkaline media,exhibiting a half-wave potential(E_(1/2))of 0.87 V,surpassing that of commercial Pt/C(E_(1/2)=0.85 V).When applied to both aqueous and flexible ZAB configurations,the FNC catalyst achieved peak power densities of 172 and 85 mW cm^(-2),respectively,along with exceptional cycling stabilities exceeding 5300 and 302 h,respectively.This study establishes a novel approach for designing metal-free ORR catalysts and next-generation ZABs,particularly for use in flexible and wearable microelectronic devices.展开更多
A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible ...A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.展开更多
Tumor heterogeneity and diversity significantly undermine the effectiveness of monotherapy.Collaborative therapy emerges as a promising approach to mitigate tumor recurrence resulting from monotherapy.Combining chemod...Tumor heterogeneity and diversity significantly undermine the effectiveness of monotherapy.Collaborative therapy emerges as a promising approach to mitigate tumor recurrence resulting from monotherapy.Combining chemodynamic therapy(CDT)with photothermal therapy(PTT)offers a compelling solution for eradicating residual tumor cells post-PTT.In this study,we harness the Fenton-like response facilitated by glucose oxidase(GOD)and the mild hyperthermia induced by polyethyleneimine(PEI)functionalized nitrogen-containing graphene oxide to enhance tumor therapy through a metal-free bionic nanozyme.GOD catalyzes a substantial amount of hydrogen peroxide,and,with the carrier's involvement,triggers a Fenton-like reaction,yielding a wealth of hydroxyl radicals.These hydroxyl radicals effectively target tumor cells following photothermal action,bolstering CDT and culminating in a bidirectional amplification treatment that effectively prevents tumor recurrence and metastasis.This research amalgamates the physical and chemical attributes of nanomaterials with the unique characteristics of the tumor microenvironment,presenting a compelling and efficacious alternative for tumor treatment.展开更多
Zinc-ion batteries(ZIBs) are recognized as potential energy storage devices due to their advantages of low cost, high energy density, and environmental friendliness. However, zinc anodes are subject to unavoidable zin...Zinc-ion batteries(ZIBs) are recognized as potential energy storage devices due to their advantages of low cost, high energy density, and environmental friendliness. However, zinc anodes are subject to unavoidable zinc dendrites, passivation, corrosion, and hydrogen evolution reactions during the charging and discharging of batteries, becoming obstacles to the practical application of ZIBs. Appropriate zinc metal-free anodes provide a higher working potential than metallic zinc anodes, effectively solving the problems of zinc dendrites, hydrogen evolution, and side reactions during the operation of metallic zinc anodes. The improvement in the safety and cycle life of batteries creates conditions for further commercialization of ZIBs. Therefore, this work systematically introduces the research progress of zinc metal-free anodes in “rocking chair” ZIBs. Zinc metal-free anodes are mainly discussed in four categories: transition metal oxides,transition metal sulfides, MXene(two dimensional transition metal carbide) composites, and organic compounds, with discussions on their properties and zinc storage mechanisms. Finally, the outlook for the development of zinc metal-free anodes is proposed. This paper is expected to provide a reference for the further promotion of commercial rechargeable ZIBs.展开更多
At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organ...At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas (CO and H_(2)).Both electron donor (tris(4-aminophenyl)amine,TAPA) and acceptor (4,4',4'',4'''-((1 E,1'E,1''E,1'''E)-(ethene-1,1,2,2-tetrayltetrakis (benzene-4,1-diyl))tetrakis (ethene-2,1-diyl))tetrakis (1-(4-formylbenzyl)quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic activity.Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating DRM.After 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g^(-1)for CO and H_(2),respectively,which are significantly higher than those of TPE-CHO small molecules.This excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of COP.Overall,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.展开更多
The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both t...The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both type of reactions proceed under transition metal-free conditions.In addition,the conditions for the synthesis of 3-trifluoromethylsulfinyl chromones have also been found to be applicable for the synthesis of 3-alkyl/arylsulfinyl chromones.展开更多
Metal-free carbon,as the most representative heterogeneous metal-free catalysts,have received considerable interests in electro-and thermo-catalytic reac-tions due to their impressive performance and sustainability.Ov...Metal-free carbon,as the most representative heterogeneous metal-free catalysts,have received considerable interests in electro-and thermo-catalytic reac-tions due to their impressive performance and sustainability.Over the past decade,well-designed carbon catalysts with tunable structures and heteroatom groups coupled with various characterization techniques have proposed numerous reaction mechanisms.However,active sites,key intermediate species,precise structure-activity relationships and dynamic evolution processes of carbon catalysts are still rife with controversies due to the monotony and limitation of used experimental methods.In this Review,we sum-marize the extensive efforts on model catalysts since the 2000s,particularly in the past decade,to overcome the influences of material and structure limitations in metal-free carbon catalysis.Using both nanomolecule model and bulk model,the real contribution of each alien species,defect and edge configuration to a series of fundamentally important reactions,such as thermocatalytic reactions,electrocatalytic reactions,were systematically studied.Combined with in situ techniques,isotope labeling and size control,the detailed reaction mechanisms,the precise 2D structure-activity relationships and the rate-determining steps were revealed at a molecular level.Furthermore,the outlook of model carbon catalysis has also been proposed in this work.展开更多
X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of applica...X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of application contexts,a wealth of opportunities is entailed with the practical utilization of both organic and inorganic X-ray detection materials.A novel and promising contender in this realm is the emergence of metal-free organic halide perovskites(O-PVSKs),offering great opportunities and tremendous potential in X-ray detection.This potential can be attributed to the distinct crystalline configuration of O-PVSKs,where organic constituents are structured into an ABX3perovskite arrangement.Consequently,O-PVSKs exhibit captivating characteristics reminiscent of organic materials,such as lightweight nature and modifiability,all while retaining the distinctive traits associated with halide perovskites ranging from diverse structures to tunable optoelectronic properties.This review article delves into the intrinsic attributes of O-PVSKs and critically examines the viability of O-PVSKs in X-ray detection,through which key features that distinguish O-PVSKs from traditional organic semiconductors and perovskites are outlined.This is followed by a perspective given on their future avenues for exploration.展开更多
A new strategy for the metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid Boron has been first identified.Bis(pentafluorophenyl)(phenoxy)borane was used as a cat...A new strategy for the metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid Boron has been first identified.Bis(pentafluorophenyl)(phenoxy)borane was used as a catalyst for the polymerization reaction system.And polytetrahydrofuran with high molecular weight and narrow molecular weight distribution could be obtained.The proposed mechanism was studied by MALDI-TOF,ESI-MS and O-18 isotope labeling analyses as a metal-free coordination insertion mechanism.展开更多
Recently electrochemical synthesis of H_(2)O_(2)through oxygen reduction reaction(ORR)via 2e^(-)pathway is considered as a green and on-site route.However,it still remains a big challenge for fabricating novel metal-f...Recently electrochemical synthesis of H_(2)O_(2)through oxygen reduction reaction(ORR)via 2e^(-)pathway is considered as a green and on-site route.However,it still remains a big challenge for fabricating novel metal-free catalysts under acidic solutions,since it suffers from high overpotential due to the intrinsically week*OOH adsorption.Herein,a co-doped carbon nanosheet(O/N–C)catalyst toward regulating O and N content was synthesized for improving the selectivity and activity of H_(2)O_(2)electrosynthesis process.The O/N–C exhibits outstanding 2e-ORR performance with low onset potential of 0.4 V(vs.RHE)and a selectivity of 92.4%in 0.1 mol/L HClO_(4)solutions.The in situ electrochemical impedance spectroscopy(EIS)tests reveals that the N incorporation contributes to the fast ORR kinetics.The density functional theory(DFT)calculations demonstrate that the binding strength of*OOH was optimized by the co-doping of oxygen and nitrogen at certain content,and the O/N–C–COOH site exhibits a lower theoretical overpotential for H_(2)O_(2)formation than O–C–COOH site.Furthermore,the promoted kinetics for typical organic dye degradation in simultaneous electron-Fenton process on O/N–C catalyst was demonstrated particularly for broadening its environmental application.展开更多
The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts inclu...The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers and carbon materials for the synthesis of cyclic carbonates by the cycloaddition of carbon dioxide to epoxides are reviewed. Recent advances in the design of the catalysts and the understanding of the reaction mechanism are summarized and discussed. The synergistic effects of organic bases and hydrogen bond donors, organic bases and nucleophilic anions, hydrogen bond donors and nucleophilic anions and active components and supports are highlighted. The challenge is to develop metal-free catalysts suitable for carbon dioxide capture and fixation. The ultimate goal is to synthesize cyclic carbonates in a flow reactor directly using carbon dioxide from industrial flue gas at ambient temperature and atmospheric pressure. By using synergetic effects, a multi-functional approach can meet the design strategy of metal-free catalysts for carbon dioxide adsorption and activation as well as epoxide ring opening.展开更多
Electrochemical CO2 reduction to chemicals or fuels presents one of the most promising strategies for managing the global carbon balance, which yet poses a significant challenge due to lack of efficient and durable el...Electrochemical CO2 reduction to chemicals or fuels presents one of the most promising strategies for managing the global carbon balance, which yet poses a significant challenge due to lack of efficient and durable electrocatalyst as well as the understanding of the CO2 reduction reaction(CO2RR) mechanism.Benefiting from the large surface area, high electrical conductivity, and tunable structure, carbon-based metal-free materials(CMs) have been extensively studied as cost-effective electrocatalysts for CO2RR.The development of CMs with low cost, high activity and durability for CO2RR has been considered as one of the most active and competitive directions in electrochemistry and material science.In this review article,some up-to-date strategies in improving the CO2RR performance on CMs are summarized.Specifically, the approaches to optimize the adsorption of CO2RR intermediates, such as tuning the physical and electronic structure are introduced, which can enhance the electrocatalytic activity of CMs effectively.Finally, some design strategies are proposed to prepare CMs with high activity and selectivity for CO2RR.展开更多
Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity.In this study,boron phosphate crystals with a three-dimensionally ...Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity.In this study,boron phosphate crystals with a three-dimensionally interconnected ordered macroporous structure and a robust framework were fabricated and used as stable and selective catalysts in the oxidative dehydrogenation(ODH)of propane.Due to the improved mass diffusion and higher number of exposed active sites in the ordered macroporous structure,the catalyst exhibited a remarkable olefin productivity of^16 golefin gcat^-1 h^-1,which is up to 2–100 times higher than that of ODH catalysts reported to date.The selectivity for olefins was 91.5%(propene:82.5%,ethene:9.0%)at 515℃,with a propane conversion of 14.3%.At the same time,the selectivity for the unwanted deep-oxidized CO2 product remained less than 1.0%.The tri-coordinated surface boron species were identified as the active catalytic sites for the ODH of propane.This study provides a route for preparing a new type of metal-free catalyst with stable structure against oxidation and remarkable catalytic activity,which may represent a potential candidate to promote the industrialization of the ODH process.展开更多
Nanocarbon materials have been used as important metal-free catalysts for various reactions including alkane dehydrogenation.However,clarifying the active sites and tuning the nanocarbon structure for direct dehydroge...Nanocarbon materials have been used as important metal-free catalysts for various reactions including alkane dehydrogenation.However,clarifying the active sites and tuning the nanocarbon structure for direct dehydrogenation have always been significantly challenging owing to the lack of fundamental understanding of the structure and surface properties of carbon materials.Herein,mesoporous carbon materials with different pore ordering and surface properties were synthesized through a soft-templating method with different formaldehyde/resorcinol ratios and carbonization temperatures and used for catalytic dehydrogenation of propane to propylene.The highly ordered mesoporous carbons were found to have higher catalytic activities than disordered and ordered mesoporous carbons,mainly because the highly ordered mesopores favor mass transportation and provide more accessible active sites.Furthermore,mesoporous carbons can provide a large amount of surface active sites owing to their high surface areas,which is favorable for propane dehydrogenation reaction.To control the surface oxygenated functional groups,highly ordered mesoporous carbons were carbonized at different temperatures(600,700,and 800℃).The propylene formation rates exhibit an excellent linear relationship with the number of ketonic C=O groups,suggesting that C=O groups are the most possible active sites.展开更多
Two-dimensional(2D)carbon nitride(CN)photocatalysts are attracting extensive attention owing to their excellent photocatalytic properties.In this study,we successfully prepared CN materials with heterogeneous structur...Two-dimensional(2D)carbon nitride(CN)photocatalysts are attracting extensive attention owing to their excellent photocatalytic properties.In this study,we successfully prepared CN materials with heterogeneous structures via hydrothermal treatment,high-temperature roasting,ball milling,sintering,and other processes.Benefitting from interface interactions in hybrid architectures,the CN photocatalysts exhibited high photocatalytic activity.The rate of hydrogen production using these CN photocatalysts reached 17028.82μmol h^(−1)g^(−1),and the apparent quantum efficiency was 11.2%at 420 nm.The ns-level time-resolved photoluminescence(PL)spectra provided information about the time-averaged lifetime of fluorescence charge carriers;the lifetime of the charge carriers causing the fluorescence of CN reached 9.99 ns.Significantly,the CN photocatalysts displayed satisfactory results in overall water splitting without the addition of sacrificial agents.The average hydrogen and oxygen production rates were 270.95μmol h^(−1)g^(−1)and 115.21μmol h^(−1)g^(−1)in 7 h,respectively,which were promising results for the applications of the catalysts in overall water splitting processes.We investigated the high efficiency of the prepared CN photocatalysts via a series of tests(UV-vis diffuse reflectance spectroscopy,photocurrent response measurements,PL emission spectroscopy,time-resolved PL spectroscopy,and Brunauer-Emmett-Teller analysis).Furthermore,the Mott-Schottky plot and current-voltage curve were acquired via electrochemical tests.The fabricated CN photocatalyst had a small p-n junction in its heterogeneous structure,which further enhanced its photocatalytic efficiency.Therefore,this work can promote the development of CN photocatalysts.展开更多
文摘An efficient acetic acid mediated metal-free oxidative C—H cross coupling of imidazo[1,2-a]pyridines with glyoxal hydrates has been developed under air atmosphere.The present protocol exhibits broad substrate scope,good functional group tolerance,and enables the construction of a series of 1,2-dicarbonyl imidazo[1,2-a]pyridines in good yields.The reaction mechanism studies suggest that the reactions proceed through the electrophilic substitution and subsequent oxidation pathway.
文摘Metal-free carbon catalysts have garnered significant attention since their inception.Despite substantial advancements,including widely adopted strategies such as heteroatom doping and defect engineering,their catalytic performance remains inferior to that of metal-based catalysts.In this study,we have predicted and demonstrated that the curvature of carbon plays a pivotal role in the adsorption of acetylene and the overall catalytic performance.First-principles calculations suggest that a tip-enhanced local electric field at the defect site on the curved carbon catalyst enhances the reaction kinetics for acetylene hydrochlorination.The experimental results highlight the structural advantages of the curved defect site,revealing that high-curvature defective carbon(HCDC)demonstrates an adsorption capacity for acetylene that is almost two orders of magnitude higher than that of defective carbon.Notably,HCDC achieves an acetylene conversion of up to 90%at 220℃under a gas hourly space velocity of 300 h^(-1),significantly surpassing the performance of the benchmark 0.25%Au/AC catalyst.This proof-of-concept study reveals the fundamental mechanisms driving the superior performance of carbon catalysts with curved nanostructures and presents a straightforward,environmentally friendly method for large-scale production of carbon materials with precisely controlled nanostructures.It highlights the potential for commercializing metal-free carbon catalysts in acetylene hydrochlorination and related heterogenous catalytic reactions.
基金funded by the National Natural Science Foundation of China(Grant Nos.52205457 and 52422511)the National Key R&D Program of China(Grant No.2022YFB4701000)+3 种基金the Guangdong Basic and Applied Basic Research Foundation,China(Grant Nos.2024A1515010043,2025A1515010890 and 2022B1515120011)the Young Talent Support Project of Guangzhou Association for Science and Technology(Grant No.QT2024-010)the Guangzhou Basic and Applied Basic Research Foundation(Grant No.SL2024A04J01501)the State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment(Grant No.JMDZ202303).
文摘The development of high-voltage tandem thin-film supercapacitors(TFSCs)has been limited by the issues such as expensive electrode materials,indispensable commercial separators and metal current collectors,and complex manufacturing processes.Herein,we develop a potentially scalable approach to address all these issues by using CO_(2) laser pyrolysis of polyimide(PI)paper into the three-dimensional(3D)morphology of graphene paper in air.The formation process and mechanism of PI to graphene were clarified by microstructure and chemical characterizations and reaction molecular dynamics.The influences of laser scan density,power,defocus,and scan speed on the sheet resistance,longitudinal resistance,Raman spectra,and electrochemical performance of graphene papers were systematically investigated.Results indicate that high-quality graphene papers with ultralow sheet resistance(4.88Ω·square^(-1))and longitudinal resistance(3.46Ω)and extra-large crystalline size(96.1 nm)were achieved under optimized process parameters.The graphene papers can simultaneously serve as active electrode materials,current collectors,and interconnectors.The active area of electrodes is defined by a PI mask,with the help of which a hydrogel electrolyte functions as a separator.The assembled graphene paper-based TFSCs demonstrate outstanding electrochemical performance and mechanical flexibility,with the areal capacitance of 54.5 mF·cm^(-2),energy density of 10.9µWh·cm^(-2),and cycle stability retention of 86.9%over 15000 cycles.Moreover,all the tandem metal-free TFSCs,ranging from 1 to 160 cells,show excellent performance uniformity.The output voltage increases linearly from 1.2 V to 200 V.Significantly,the 160-tandem TFSCs exhibit a high voltage density within a compact volume of∼3.8 cm^(3).This work provides an avenue for achieving tandem metal-free TFSCs in a simple and efficient manner.
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2021ME126,ZR2022ME139,ZR2021ME149)the Key Research and Development Program of Shandong Province-Project for Enhancing the Innovation Capacity of Teschnology-based Small and Medium-sized Enterprises(No.2024TSGC0957)the Research Foundation of Liaocheng University(Nos.318012012 , 318011905).
文摘We report a general method for the synthesis of polymer-decorated metal-organic frameworks(MOFs)for the fabrication of superhy-drophobic materials through photoinduced metal-free atom transfer radical polymerization(ATRP).Firstly,an MOF material,ZIF-8-NH_(2),was syn-thesized through the self-assembly of metal ions and organic ligands at room temperature.ZIF-8-NH_(2)was then reacted with glycidyl methacry-late(GMA)to form ZIF-8@GMA.Finally,ZIF-8@GMA-PHFBA was prepared by grafting fluorinated monomer 2,2,3,4,4,4-hexafluorobutyl acrylate(HFBA),from the ZIF-8@GMA surface via photoinduced ATRP under 365 nm UV light.The structural evolution during the metal-free ATRP modifi-cation of ZIF-8-NH_(2)was characterized by Fourier transform infrared spectroscopy(FTIR),X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and thermogravimetry analysis(TGA).The test results verified that ZIF-8-NH_(2)and ZIF-8@GMA-PHFBA were successfully synthesized,and that the surface graft polymerization did not change the structure and morphology of ZIF-8-NH_(2).After anchoring the ZIF-8@GMA-PHFBA hybrid material on the fabric surface,the water contact angle(WCA)of the ZIF-8@GMA-PHFBA hy-brid material-modified fabric surface reached 154.2,which achieved a superhydrophobic state.In addition,the oil-water separation experiment and self-cleaning test demonstrated that the ZIF-8@GMA-PHFBA hybrid material-modified fabric has an excellent oil-water separation effect and self-cleaning performance.This material shows promising potential for applications in self-cleaning and oil-water separation technologies.
文摘The development of metal-free carbon catalysts has garnered significant attention as a promising approach to address the challenges of sustainable catalysis,particularly in the replacement of toxic and environmentally hazardous mercury-based systems for the coal-based PVC industry.Within a decade of development,the catalytic performance of carbon catalysts has been improved greatly and even shows superiorities over metal catalysts in some cases,which have demonstrated great potential as sustainable alternatives to mercury catalysts.This review provides a comprehensive summary of the recent advancements in carbon catalysts for acetylene hydrochlorination.It encompasses a wide range of aspects,including the identification of active sites from heteroatom doping to intrinsic carbon defects,the various synthetic strategies employed,the reaction and deactivation mechanisms of carbon catalysts,and the current insights into the key challenges that are encountered on the journey from laboratory research to scalable commercialization within the field of carbon catalysts.The review offers foundational insights and practical guidelines for designing green carbon catalysts systems,not only for acetylene hydrochlorination but also for other heterogeneous catalytic reactions.
文摘Designing exceptional-performance and long-lasting oxygen reduction reaction(ORR)catalysts is a critical challenge for the development of rechargeable Zn-air batteries(ZABs).In this study,we introduce a metal-free ORR catalyst composed of F-N co-doped hollow carbon(FNC),specifically engineered to address the limitations of conventional catalysts.The FNC catalysts were synthesized using a template-assisted pyrolysis method,resulting in a hollow,porous architecture with a high specific surface area and numerous active sites.Concurrently,F doping optimized the electronic configuration of pyridinic nitrogen.The introduction of C-F bonds reduced the reaction energy barrier,and the resulting N-C-F configuration enhanced the stability of the nitrogen center.The catalyst exhibits outstanding ORR activity in alkaline media,exhibiting a half-wave potential(E_(1/2))of 0.87 V,surpassing that of commercial Pt/C(E_(1/2)=0.85 V).When applied to both aqueous and flexible ZAB configurations,the FNC catalyst achieved peak power densities of 172 and 85 mW cm^(-2),respectively,along with exceptional cycling stabilities exceeding 5300 and 302 h,respectively.This study establishes a novel approach for designing metal-free ORR catalysts and next-generation ZABs,particularly for use in flexible and wearable microelectronic devices.
基金financial support from the National Natural Science Foundation of China(No.82003585)the Program for Science&Technology Innovation Talents in Universities of Henan Province(No.24HASTIT069)+5 种基金the Technical Innovation Team of Henan Normal University(No.2022TD03)the Special Project for Fundamental Research in University of Henan Province(No.23ZX009)the Henan Science and Technology Program(No.232102310364)the Key Project of Henan Educational Committee(No.22A150041)Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)the Young Core Instructor Training Program of Xinyang Agriculture and Forestry University(2023)。
文摘A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.
基金financial support from the National Natural Science Foundation of China(Nos.82202354,U20A20338,82201247)The Summit Advancement Disciplines of Zhejiang Province(Wenzhou Medical University-Pharmaceutics)the Key R&D Program of Zhejiang Province(No.2021C04019)。
文摘Tumor heterogeneity and diversity significantly undermine the effectiveness of monotherapy.Collaborative therapy emerges as a promising approach to mitigate tumor recurrence resulting from monotherapy.Combining chemodynamic therapy(CDT)with photothermal therapy(PTT)offers a compelling solution for eradicating residual tumor cells post-PTT.In this study,we harness the Fenton-like response facilitated by glucose oxidase(GOD)and the mild hyperthermia induced by polyethyleneimine(PEI)functionalized nitrogen-containing graphene oxide to enhance tumor therapy through a metal-free bionic nanozyme.GOD catalyzes a substantial amount of hydrogen peroxide,and,with the carrier's involvement,triggers a Fenton-like reaction,yielding a wealth of hydroxyl radicals.These hydroxyl radicals effectively target tumor cells following photothermal action,bolstering CDT and culminating in a bidirectional amplification treatment that effectively prevents tumor recurrence and metastasis.This research amalgamates the physical and chemical attributes of nanomaterials with the unique characteristics of the tumor microenvironment,presenting a compelling and efficacious alternative for tumor treatment.
基金financially supported by the National Natural Science Foundation of China (Nos.51872090 and51772097)the Hebei Natural Science Fund for Distinguished Young Scholar,China (No.E2019209433)+2 种基金the Youth Talent Program of Hebei Provincial Education Department,China (No.BJ2018020)the Natural Science Foundation of Hebei Province,China (No.E2020209151)the Science and Technology Project of Hebei Education Department,China (No.SLRC2019028)。
文摘Zinc-ion batteries(ZIBs) are recognized as potential energy storage devices due to their advantages of low cost, high energy density, and environmental friendliness. However, zinc anodes are subject to unavoidable zinc dendrites, passivation, corrosion, and hydrogen evolution reactions during the charging and discharging of batteries, becoming obstacles to the practical application of ZIBs. Appropriate zinc metal-free anodes provide a higher working potential than metallic zinc anodes, effectively solving the problems of zinc dendrites, hydrogen evolution, and side reactions during the operation of metallic zinc anodes. The improvement in the safety and cycle life of batteries creates conditions for further commercialization of ZIBs. Therefore, this work systematically introduces the research progress of zinc metal-free anodes in “rocking chair” ZIBs. Zinc metal-free anodes are mainly discussed in four categories: transition metal oxides,transition metal sulfides, MXene(two dimensional transition metal carbide) composites, and organic compounds, with discussions on their properties and zinc storage mechanisms. Finally, the outlook for the development of zinc metal-free anodes is proposed. This paper is expected to provide a reference for the further promotion of commercial rechargeable ZIBs.
基金supported by National Natural Science Foundation of China (Nos. 22274039 and 22178089)Hunan Provincial Innovation Foundation for Postgraduate (No.CX20220392)。
文摘At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas (CO and H_(2)).Both electron donor (tris(4-aminophenyl)amine,TAPA) and acceptor (4,4',4'',4'''-((1 E,1'E,1''E,1'''E)-(ethene-1,1,2,2-tetrayltetrakis (benzene-4,1-diyl))tetrakis (ethene-2,1-diyl))tetrakis (1-(4-formylbenzyl)quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic activity.Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating DRM.After 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g^(-1)for CO and H_(2),respectively,which are significantly higher than those of TPE-CHO small molecules.This excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of COP.Overall,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.
基金financially supported by National Natural Science Foundation of China(No.22161022)。
文摘The new reactions between o-hydroxyphenyl enaminones and Langlois reagent(CF_(3)SO_(2)Na)for the tunable synthesis of 3-(trifluoromethylthio)chromones and 3-trifluoromethylsulfinyl chromones are reported herein.Both type of reactions proceed under transition metal-free conditions.In addition,the conditions for the synthesis of 3-trifluoromethylsulfinyl chromones have also been found to be applicable for the synthesis of 3-alkyl/arylsulfinyl chromones.
基金We are grateful for financial support from the“Hundred Talents Program”of the Chinese Academy of Sciences and the“Young Talents Training Program”of the Shanghai Branch of the Chinese Academy of Sciences.We acknowledge the financial support from the National Science Youth Foundation of China(22202205)Xiamen City Natural Science Foundation of China(3502Z20227256)Fujian Provincial Natural Science Foundation of China(2022J01502).
文摘Metal-free carbon,as the most representative heterogeneous metal-free catalysts,have received considerable interests in electro-and thermo-catalytic reac-tions due to their impressive performance and sustainability.Over the past decade,well-designed carbon catalysts with tunable structures and heteroatom groups coupled with various characterization techniques have proposed numerous reaction mechanisms.However,active sites,key intermediate species,precise structure-activity relationships and dynamic evolution processes of carbon catalysts are still rife with controversies due to the monotony and limitation of used experimental methods.In this Review,we sum-marize the extensive efforts on model catalysts since the 2000s,particularly in the past decade,to overcome the influences of material and structure limitations in metal-free carbon catalysis.Using both nanomolecule model and bulk model,the real contribution of each alien species,defect and edge configuration to a series of fundamentally important reactions,such as thermocatalytic reactions,electrocatalytic reactions,were systematically studied.Combined with in situ techniques,isotope labeling and size control,the detailed reaction mechanisms,the precise 2D structure-activity relationships and the rate-determining steps were revealed at a molecular level.Furthermore,the outlook of model carbon catalysis has also been proposed in this work.
基金support from the National Natural Science Foundation of China(Nos.62205154 and 62205155)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(Nos.NY221112 and NY222104)。
文摘X-ray detection plays a crucial role across various aspects of our daily lives,encompassing medical diagnoses,security screenings,and non-destructive examinations in industrial settings.Given the wide array of application contexts,a wealth of opportunities is entailed with the practical utilization of both organic and inorganic X-ray detection materials.A novel and promising contender in this realm is the emergence of metal-free organic halide perovskites(O-PVSKs),offering great opportunities and tremendous potential in X-ray detection.This potential can be attributed to the distinct crystalline configuration of O-PVSKs,where organic constituents are structured into an ABX3perovskite arrangement.Consequently,O-PVSKs exhibit captivating characteristics reminiscent of organic materials,such as lightweight nature and modifiability,all while retaining the distinctive traits associated with halide perovskites ranging from diverse structures to tunable optoelectronic properties.This review article delves into the intrinsic attributes of O-PVSKs and critically examines the viability of O-PVSKs in X-ray detection,through which key features that distinguish O-PVSKs from traditional organic semiconductors and perovskites are outlined.This is followed by a perspective given on their future avenues for exploration.
基金funded by the National Key R&D Program of China(No.2021YFA1501700)the Science and Technology Development Plan of Jilin Province(Nos.20230101042JC,20210201059GX)+2 种基金the National Natural Science Foundation of China,Basic Science Center Program(No.51988102)the National Natural Science Foundation of China(Nos.52203017,52073272 and 22293062)Bureau of International Cooperation Chinese Academy of Sciences(No.029GJHZ2023017MI)。
文摘A new strategy for the metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid Boron has been first identified.Bis(pentafluorophenyl)(phenoxy)borane was used as a catalyst for the polymerization reaction system.And polytetrahydrofuran with high molecular weight and narrow molecular weight distribution could be obtained.The proposed mechanism was studied by MALDI-TOF,ESI-MS and O-18 isotope labeling analyses as a metal-free coordination insertion mechanism.
基金supported by the National Natural Science Foundation of China(Nos.U22A20432,22278364,22211530045,22178308)the Fundamental Research Funds for the Central Universities(Nos.226-2022-00044,226-2022-00055)+6 种基金the Research Funds of Institute of Zhejiang University-Quzhou(No.IZQ2021KJ2003)National Key Research and Development Program of China(No.2022YFB4002100)the development project of Zhejiang Province's"Jianbing"and"Lingyan"(No.2023C01226)the Startup Foundation for Hundred-Talent Program of Zhejiang Universitythe Science Foundation of Donghai Laboratory(No.DH_(2)022ZY0009)Zhejiang University Global Partnership Fundthe China Postdoctoral Science Foundation(No.2021M702813)。
文摘Recently electrochemical synthesis of H_(2)O_(2)through oxygen reduction reaction(ORR)via 2e^(-)pathway is considered as a green and on-site route.However,it still remains a big challenge for fabricating novel metal-free catalysts under acidic solutions,since it suffers from high overpotential due to the intrinsically week*OOH adsorption.Herein,a co-doped carbon nanosheet(O/N–C)catalyst toward regulating O and N content was synthesized for improving the selectivity and activity of H_(2)O_(2)electrosynthesis process.The O/N–C exhibits outstanding 2e-ORR performance with low onset potential of 0.4 V(vs.RHE)and a selectivity of 92.4%in 0.1 mol/L HClO_(4)solutions.The in situ electrochemical impedance spectroscopy(EIS)tests reveals that the N incorporation contributes to the fast ORR kinetics.The density functional theory(DFT)calculations demonstrate that the binding strength of*OOH was optimized by the co-doping of oxygen and nitrogen at certain content,and the O/N–C–COOH site exhibits a lower theoretical overpotential for H_(2)O_(2)formation than O–C–COOH site.Furthermore,the promoted kinetics for typical organic dye degradation in simultaneous electron-Fenton process on O/N–C catalyst was demonstrated particularly for broadening its environmental application.
基金supported by the National Science and Technology Support Project of China(2013BAC11B03)the National Natural Science Foundation of China(21401054,21476065,21273067)the Graduate Student Scientific Research Innovation Fund Project of Hunan Province(CX2015B082)~~
文摘The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers and carbon materials for the synthesis of cyclic carbonates by the cycloaddition of carbon dioxide to epoxides are reviewed. Recent advances in the design of the catalysts and the understanding of the reaction mechanism are summarized and discussed. The synergistic effects of organic bases and hydrogen bond donors, organic bases and nucleophilic anions, hydrogen bond donors and nucleophilic anions and active components and supports are highlighted. The challenge is to develop metal-free catalysts suitable for carbon dioxide capture and fixation. The ultimate goal is to synthesize cyclic carbonates in a flow reactor directly using carbon dioxide from industrial flue gas at ambient temperature and atmospheric pressure. By using synergetic effects, a multi-functional approach can meet the design strategy of metal-free catalysts for carbon dioxide adsorption and activation as well as epoxide ring opening.
基金supported by the National Key R&D Program of China (2016YFB0600902)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17000000)+2 种基金Dalian National Laboratory for Clean Energy (DNL180401)the Youth Innovation Promotion Association CASthe Singapore Ministry of Education Academic Research Fund (AcRF) Tier 1: RG9/17, RG115/17, RG115/18 and Tier 2: MOE2016-T2-2-004
文摘Electrochemical CO2 reduction to chemicals or fuels presents one of the most promising strategies for managing the global carbon balance, which yet poses a significant challenge due to lack of efficient and durable electrocatalyst as well as the understanding of the CO2 reduction reaction(CO2RR) mechanism.Benefiting from the large surface area, high electrical conductivity, and tunable structure, carbon-based metal-free materials(CMs) have been extensively studied as cost-effective electrocatalysts for CO2RR.The development of CMs with low cost, high activity and durability for CO2RR has been considered as one of the most active and competitive directions in electrochemistry and material science.In this review article,some up-to-date strategies in improving the CO2RR performance on CMs are summarized.Specifically, the approaches to optimize the adsorption of CO2RR intermediates, such as tuning the physical and electronic structure are introduced, which can enhance the electrocatalytic activity of CMs effectively.Finally, some design strategies are proposed to prepare CMs with high activity and selectivity for CO2RR.
文摘Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity.In this study,boron phosphate crystals with a three-dimensionally interconnected ordered macroporous structure and a robust framework were fabricated and used as stable and selective catalysts in the oxidative dehydrogenation(ODH)of propane.Due to the improved mass diffusion and higher number of exposed active sites in the ordered macroporous structure,the catalyst exhibited a remarkable olefin productivity of^16 golefin gcat^-1 h^-1,which is up to 2–100 times higher than that of ODH catalysts reported to date.The selectivity for olefins was 91.5%(propene:82.5%,ethene:9.0%)at 515℃,with a propane conversion of 14.3%.At the same time,the selectivity for the unwanted deep-oxidized CO2 product remained less than 1.0%.The tri-coordinated surface boron species were identified as the active catalytic sites for the ODH of propane.This study provides a route for preparing a new type of metal-free catalyst with stable structure against oxidation and remarkable catalytic activity,which may represent a potential candidate to promote the industrialization of the ODH process.
基金supported by the National Natural Science Foundation of China(21421001,21573115)the Fundamental Research Funds for the Central Universities(63185015)the Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(2017-K13)~~
文摘Nanocarbon materials have been used as important metal-free catalysts for various reactions including alkane dehydrogenation.However,clarifying the active sites and tuning the nanocarbon structure for direct dehydrogenation have always been significantly challenging owing to the lack of fundamental understanding of the structure and surface properties of carbon materials.Herein,mesoporous carbon materials with different pore ordering and surface properties were synthesized through a soft-templating method with different formaldehyde/resorcinol ratios and carbonization temperatures and used for catalytic dehydrogenation of propane to propylene.The highly ordered mesoporous carbons were found to have higher catalytic activities than disordered and ordered mesoporous carbons,mainly because the highly ordered mesopores favor mass transportation and provide more accessible active sites.Furthermore,mesoporous carbons can provide a large amount of surface active sites owing to their high surface areas,which is favorable for propane dehydrogenation reaction.To control the surface oxygenated functional groups,highly ordered mesoporous carbons were carbonized at different temperatures(600,700,and 800℃).The propylene formation rates exhibit an excellent linear relationship with the number of ketonic C=O groups,suggesting that C=O groups are the most possible active sites.
文摘Two-dimensional(2D)carbon nitride(CN)photocatalysts are attracting extensive attention owing to their excellent photocatalytic properties.In this study,we successfully prepared CN materials with heterogeneous structures via hydrothermal treatment,high-temperature roasting,ball milling,sintering,and other processes.Benefitting from interface interactions in hybrid architectures,the CN photocatalysts exhibited high photocatalytic activity.The rate of hydrogen production using these CN photocatalysts reached 17028.82μmol h^(−1)g^(−1),and the apparent quantum efficiency was 11.2%at 420 nm.The ns-level time-resolved photoluminescence(PL)spectra provided information about the time-averaged lifetime of fluorescence charge carriers;the lifetime of the charge carriers causing the fluorescence of CN reached 9.99 ns.Significantly,the CN photocatalysts displayed satisfactory results in overall water splitting without the addition of sacrificial agents.The average hydrogen and oxygen production rates were 270.95μmol h^(−1)g^(−1)and 115.21μmol h^(−1)g^(−1)in 7 h,respectively,which were promising results for the applications of the catalysts in overall water splitting processes.We investigated the high efficiency of the prepared CN photocatalysts via a series of tests(UV-vis diffuse reflectance spectroscopy,photocurrent response measurements,PL emission spectroscopy,time-resolved PL spectroscopy,and Brunauer-Emmett-Teller analysis).Furthermore,the Mott-Schottky plot and current-voltage curve were acquired via electrochemical tests.The fabricated CN photocatalyst had a small p-n junction in its heterogeneous structure,which further enhanced its photocatalytic efficiency.Therefore,this work can promote the development of CN photocatalysts.
