Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic com...Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C_(3)N_(4) in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C_(3)N_(4).It highlights the recent progress of g-C_(3)N_(4) nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C_(3)N_(4) nanostructures for a variety of applications might find our review paper to be a useful resource.展开更多
Ionogels,generally formed by immobilizing ionic liquids(ILs)with polymer gelators,hold considerable promise as quasi-solid-state electrolytes(QSSEs)for lithium metal batteries(LMBs)due to their high safety and electro...Ionogels,generally formed by immobilizing ionic liquids(ILs)with polymer gelators,hold considerable promise as quasi-solid-state electrolytes(QSSEs)for lithium metal batteries(LMBs)due to their high safety and electrode compatibility.However,their practical use in high-temperature LMBs suffers from the softened polymer chains of gelator at high temperatures,leading to liquid leakage and severe growth of Li dendrite.Here,a novel inorganic ionogel(PCNIL)combining lithium salt-containing IL with porous graphitic carbon nitride nanosheets(PCN)is developed through direct physical mixing.PCNIL exhibits a superior ionic conductivity(0.75 mS cm^(-1))at room temperature similar to that of neat IL electrolyte(LiIL)and a Li^(+)transference number(0.56)greatly higher than that of Li-IL(0.20).Furthermore,PCNIL maintains a temperature-independent shear storage modulus of up to 5 MPa from room temperature to 150℃.Consequently,the Li|PCNIL|Li symmetrical cell demonstrates extended reversible lithium plating/stripping over 1200 h without dendritic growth.The robust mechanical strength,excellent thermal stability,and electrochemical stability of PCNIL allow Li|PCNIL|LiFePO_(4)cells to operate stably in a wide temperature range of 25–150℃.展开更多
Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various discipline...Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various disciplines,particularly in energy conversion and storage.Its recent demonstrations of high potential in supercapacitor applications mark it as a promising alternative to graphene within the realm of materials science.Numerous favorable features,such as chemical and thermal stability,abundant nitrogen content,eco-friendly attributes,and gentle conditions for synthesis,are shown.This review summarizes recent advancements in the use of g-C_(3)N_(4)and its composites as electrodes for supercapacitors,highlighting the advantages and issues associated with g-C_(3)N_(4)in these applications.This emphasizes situations where the composition of g-C_(3)N_(4)with other materials,such as metal oxides,metal chalcogenides,carbon materials,and conducting polymers,overcomes its limitations,leading to composite materials with improved functionalities.This review discusses the challenges that still need to be addressed and the possible future roles of g-C_(3)N_(4)in the research of advanced supercapacitor technology,such as battery-hybrid supercapacitors,flexible supercapacitors,and photo-supercapacitors.展开更多
Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping...Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.展开更多
Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assist...Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assisted method to induce graphitic nanodomains and micro-mesopores into nitrogen-doped carbons.This study elucidates that these graphitic nanodomains are beneficial for Na+storage.The obtained N-doped carbon(As8Mg)electrode achieved a reversible capacity of 254 mA h g^(-1)at 0.1 A g^(-1).Moreover,the As8Mg-based SIC device achieves high combinations of power/energy densities(53 W kg^(-1)at 224 Wh kg^(-1)and 10410 W kg^(-1)at 51 Wh kg^(-1))with outstanding cycle stability(99.7%retention over 600 cycles at 0.2 A g^(-1)).Our findings provide insights into optimizing carbon’s microstructure to boost sodium storage in the pseudocapacitive mode.展开更多
The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived fro...The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).展开更多
Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme altern...Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.展开更多
Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hy...Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hydrogen(H_(2))and oxygen(O_(2)),and electrochemical methods,photocatalysis has the characteristics of low energy consumption,easy operation and less pollution,and broad application prospects in H_(2)O_(2) generation.Various photocatalysts,such as titanium dioxide(TiO_(2)),graphitic carbon nitride(g-C_(3)N_(4)),metal-organic materials,and nonmetallic materials,have been studied for H_(2)O_(2) production.Among them,g-C_(3)N_(4) materials,which are simple to synthesize and functionalize,have attracted wide attention.The electronic band structure of g-C_(3)N_(4) shows a bandgap of 2.77 eV,a valence band maximum of 1.44 V,and a conduction band minimum of−1.33 V,which theoretically meets the requirements for hydrogen peroxide production.In comparison to semiconductor materials like TiO_(2)(3.2 eV),this material has a smaller bandgap,which results in a more efficient response to visible light.However,the photocatalytic activity of g-C_(3)N_(4) and the yield of H_(2)O_(2) were severely inhibited by the electron-hole pair with high recombination rate,low utilization rate of visible light,and poor selectivity of products.Although previous reviews also presented various strategies to improve photocatalytic H_(2)O_(2) production,they did not systematically elaborate the inherent relationship between the control strategies and their energy band structure.From this point of view,this article focuses on energy band engineering and reviews the latest research progress of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production.On this basis,a strategy to improve the H_(2)O_(2) production by g-C_(3)N_(4) photocatalysis is proposed through morphology control,crystallinity and defect,and doping,combined with other materials and other strategies.Finally,the challenges and prospects of industrialization of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production are discussed and envisioned.展开更多
K-ion batteries(KIBs)have drawn much attention due to the abundant potassium reserves and wide accessibility as well as high energy density,which can be designed for large-scale energy storage systems.As the most prom...K-ion batteries(KIBs)have drawn much attention due to the abundant potassium reserves and wide accessibility as well as high energy density,which can be designed for large-scale energy storage systems.As the most promising anode materials for KIBs,graphitic carbons,especially those with an intermediate structure between the crystalline graphite and amorphous carbons become a hot research focus because of the improved rate capability and enhanced diffusion-controlled capacity at low voltage regions.Herein,we first review the structures of graphitic carbons in the view of graphitic domains and the structure changes in their K-ion intercalation compounds.Then,we summarize the preparation mechanisms and characterizations of graphitic carbons and the influence factors in their degree of graphitization.Furtherly,we illustrate the strategies to optimize their K-ion storage properties from four aspects,namely graphitic domain design,microstructure engineering,electrochemical active component regulation,and defect engineering.Finally,we propose the issues that urgently need to be solved in graphitic carbons and the possible solutions.We hope that this view could offer some inspiration for the further designing and optimizing of graphitic carbons for practical KIBs.展开更多
The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The ...The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The protective properties of mild steel coated with this nanocomposite in a marine environment were assessedusing electrochemical techniques.Thermogravimetric analysis(TGA)and Cone calorimetry tests demonstrated thatGCN/EAMS-TiO_(2)significantly enhanced the flame retardancy of the epoxy coating,reducing peak heat release rate(PHRR)and total heat release(THR)values by 88%and 70%,respectively,compared to pure EP.Salt spray testsindicated reduced water absorption and improved corrosion resistance.The optimal concentration of 0.6 wt%GCNEAMS/TiO_(2)yielded the highest resistance,with the nanocomposite achieving a coating resistance of 7.50×10^(10)Ω·cm^(2)after 28 d in seawater.The surface resistance of EP-GCN/EAMS-TiO_(2)was over 99.9 times higher than pure EP after onehour in seawater.SECM analysis showed the lowest ferrous ion dissipation(1.0 nA)for EP-GCN/EAMS-TiO_(2)coatedsteel.FE-SEM and EDX analyses revealed improved breakdown products and a durable inert nanolayered covering.Thenanocomposite exhibited excellent water resistance(water contact angle of 167°)and strong mechanical properties,withadhesive strength increasing to 18.3 MPa after 28 d in seawater.EP-GCN/EAMS-TiO_(2)shows potential as a coatingmaterial for the shipping industry.展开更多
In recent years,sodium-ion batteries(SIBs)have emerged as a promising technology for energy storage systems(ESSs)because of the abundance and affordability of sodium.Recently,metal selenides have been studied as promi...In recent years,sodium-ion batteries(SIBs)have emerged as a promising technology for energy storage systems(ESSs)because of the abundance and affordability of sodium.Recently,metal selenides have been studied as promising high-performance conversion-type anode materials in SIBs.Among them,nickel se-lenide(NiSe_(2))has received considerable attention due to its high theoretical capacity of 495 mAh g^(-1)and conductivity.However,it still suffers from poor cycling stability because of the low electrochemical reactivity,large volume expansion,and structural instability during cycles.To address these challenges,NiSe_(2)nanoparticles encapsulated in N-doped graphitic carbon fibers(NiSe_(2)@NGCF)were synthesized by using ZIF-8 as a template.NiSe_(2)@NGCF showed a high discharge capacity of 558.3 mAh g^(-1)with a fading rate of 0.14%per cycle after 200 cycles at 0.5 A g^(-1)in 0.01-3.0 V.At a very high current density of 5 A g^(-1),the capacity still displayed excellent long-term cycle life with a discharge capacity of 406.1 mAh g^(-1)with a fading rate of 0.016%per cycle after 3000 cycles.The mechanism of the excellent electrochem-ical performance of NiSe_(2)@NGCF was thoroughly investigated by ex-situ XRD,TEM,and SEM analyses.Furthermore,NiSe_(2)@NGCF//Na_(3)V_(2)(PO_(4))_(3)full-cell also delivered an excellent reversible capacity of 378.7 mAh g^(−1)at 0.1 A g^(−1)after 50 cycles,demonstrating its potential for practical application in SIBs.展开更多
Covalently bonded bridging between different semiconductors is a remarkable approach to improve the transfer of charge carriers at interfaces.In this study,we designed a ternary heterojunction(MBG)combining of molybde...Covalently bonded bridging between different semiconductors is a remarkable approach to improve the transfer of charge carriers at interfaces.In this study,we designed a ternary heterojunction(MBG)combining of molybdenum diselenide(Mo Se_(2)),black phosphorus nanosheets(Bpn)and graphitic carbon nitride(GCN).Among this MBG of Mo Se_(2)/Bpn/GCN,(i)the covalently bonded bridging effect between Bpn/GCN facilitates directional charge carrier transfer,meanwhile(ii)a Z-scheme heterojunction is formed between Mo Se_(2)/GCN to enhance the separation of photogenerated carriers.Furthermore,(iii)this composite exhibits an increased absorption for visible light.Using this MBG,photocatalytic degradation of over 98%of moxifloxacin is achieved within 20 min,with O_(2)·-confirmed as the primary photocatalytic active species.These findings provide novel insights into the construction of efficient heterojunction by covalently bonded bridging.展开更多
Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PS...Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PSDs operating at high temperatures can be found up to now.Herein,we design a new 2D/3D graphitic carbon nitride(g-C_(3)N_(4))/gallium nitride(GaN)hybrid heterojunction to construct the ultraviolet high-temperature-resistant PSD.The g-C_(3)N_(4)/GaN PSD exhibits a high position sensitivity of 355 mV mm^(-1),a rise/fall response time of 1.7/2.3 ms,and a nonlinearity of 0.5%at room temperature.The ultralow formation energy of-0.917 eV atom^(-1)has been obtained via the thermodynamic phase stability calculations,which endows g-C_(3)N_(4)with robust stability against heat.By merits of the strong built-in electric field of the 2D/3D hybrid heterojunction and robust thermo-stability of g-C_(3)N_(4),the g-C_(3)N_(4)/GaN PSD delivers an excellent position sensitivity and angle detection nonlinearity of 315 mV mm^(-1)and 1.4%,respectively,with high repeatability at a high temperature up to 700 K,outperforming most of the other counterparts and even commercial silicon-based devices.This work unveils the high-temperature PSD,and pioneers a new path to constructing g-C_(3)N_(4)-based harsh-environment-tolerant optoelectronic devices.展开更多
Graphitic carbon nitride with nanorod structure(Nr-GCN)was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment method.XRD,FTIR,SEM,N_(2)adsorption-desorption from BET,UV-V...Graphitic carbon nitride with nanorod structure(Nr-GCN)was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment method.XRD,FTIR,SEM,N_(2)adsorption-desorption from BET,UV-Vis DRS spectroscopy,and photoluminescence were used to characterize the prepared samples.Also,the photoelectrochemical behavior of nanoparticles was studied by photocurrent transient response and cyclic voltammetry analysis.Polystyrene(PS)fibrous mat was fabricated by electrospinning technique and used as a support for the stabilization of the nanoparticles.The performance of the synthesized nanoparticles and photocatalytic fibers(PS/Nr-GCN)was evaluated in oilfield-produced water treatment under visible light irradiation.During this process,oil contaminants were adsorbed by hydrophobic polystyrene fibers and simultaneously degraded by Nr-GCN.The removal efficiency of chemical oxygen demand(COD)has been obtained 96.6%and 98.4%by Nr-GCN and PS/Nr-GCN,respectively,at the optimum conditions of pH4,photocatalyst dosage 0.5 g/L,COD initial concentration 550 mg/L,and illumination time 150 min.The gas chromatography-mass spectroscopy analysis results showed 99.3%removal of total petroleum hydrocarbons using photocatalytic fibers of PS/Nr-GCN.The results demonstrated that the GCN has outstanding features like controllable morphology,visible-light-driven,and showing high potential in oily wastewater remediation.Moreover,the synergistic effect of adsorption and photocatalytic degradation is an effective technique in oilfield-produced water treatment.展开更多
With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4...With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.展开更多
A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling t...A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling time in hour） catalysts was studied using ammonia synthesis as a probe reaction. The graphitic degree and pore structure of HSGC-x supports could be successfully tuned via the variation of ball-milling time. Ru nanoparticles of different Ba-Ru-K/HSGC-x catalysts are homogeneously distributed on the supports with the particle sizes ranging from 1.6 to 2.0 nm. The graphitic degree of the support is closely related to its facile electron transfer capability and so plays an important role in improving the intrinsic catalytic performance of Ba-Ru-K/HSGC-x catalyst.展开更多
N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial ...N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial Coulombic efficiency(ICE).In this study,high N-doped and low graphitic-N carbons(LGNCs)with enhanced ICE were synthesized by taking advantage of a denitrification strategy for graphitic carbon nitride(g-C_(3)N_(4)).In brief,more than 14.5 at%of N from g-C_(3)N_(4)(55.1 at%N)was retained by reacting graphitic-N with lithium,which was subsequently removed.As graphitic-N is largely responsible for the irreversible capacity,the anode's performance was significantly increased.Compared to general N-doped carbons with high graphitic-N proportion(>50%)and low N content(<15 at%),LGNCs delivered a low proportion of 10.8%-17.2% within the high N-doping content of 14.5-42.7 at%,leading to an enhanced specific capacity of 1499.9mAh g^(-1) at an ICE of 93.7% for the optimal sample of LGNC(4:1).This study provides a facile strategy to control the N content and speciation,achieving both high Li+storage capacity and high ICE,and thus promoting research and application of N-doped carbon materials.展开更多
Pure bismuth（Bi） metal-modified graphitic carbon nitride（g-C3N4） composites（Bi-CN） with a pomegranate-like structure were prepared by an in situ method.The Bi-CN composites were used as photocatalysts for the ox...Pure bismuth（Bi） metal-modified graphitic carbon nitride（g-C3N4） composites（Bi-CN） with a pomegranate-like structure were prepared by an in situ method.The Bi-CN composites were used as photocatalysts for the oxidation of nitric oxide（NO） under visible-light irradiation.The inclusion of pure Bi metal in the g-C3N4 layers markedly improved the light absorption of the Bi-CN composites from the ultraviolet to the near-infrared region because of the typical surface plasmon resonance of Bi metal.The separation and transfer of photogenerated charge carriers were greatly accelerated by the presence of built-in Mott-Schottky effects at the interface between Bi metal and g-C3N4.As a result,the Bi-CN composite photocatalysts exhibited considerably enhanced efficiency in the photocatalytic removal of NO compared with that of Bi metal or g-C3N4 alone.The pomegranate-like structure of the Bi-CN composites and an explanation for their improved photocatalytic activity were proposed.This work not only provides a design for highly efficient g-C3N4-based photocatalysts through modification with Bi metal,but also offers new insights into the mechanistic understanding of g-C3N4-based photo catalysis.展开更多
As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemic...As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.展开更多
基金M Tahir is funded by EU H2020 Marie Skłodows-ka-Curie Fellowship(1439425).
文摘Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C_(3)N_(4) in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C_(3)N_(4).It highlights the recent progress of g-C_(3)N_(4) nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C_(3)N_(4) nanostructures for a variety of applications might find our review paper to be a useful resource.
基金support from National Natural Science Foundation of China(52072118 and 52373206)the Open Foundation of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(72275002)+2 种基金Research fund of Yue Lu Mountain Industrial Innovation Center(2023YCII0137)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(2024Z04)Natural Science Foundation of Hunan Province(2024JJ5076)。
文摘Ionogels,generally formed by immobilizing ionic liquids(ILs)with polymer gelators,hold considerable promise as quasi-solid-state electrolytes(QSSEs)for lithium metal batteries(LMBs)due to their high safety and electrode compatibility.However,their practical use in high-temperature LMBs suffers from the softened polymer chains of gelator at high temperatures,leading to liquid leakage and severe growth of Li dendrite.Here,a novel inorganic ionogel(PCNIL)combining lithium salt-containing IL with porous graphitic carbon nitride nanosheets(PCN)is developed through direct physical mixing.PCNIL exhibits a superior ionic conductivity(0.75 mS cm^(-1))at room temperature similar to that of neat IL electrolyte(LiIL)and a Li^(+)transference number(0.56)greatly higher than that of Li-IL(0.20).Furthermore,PCNIL maintains a temperature-independent shear storage modulus of up to 5 MPa from room temperature to 150℃.Consequently,the Li|PCNIL|Li symmetrical cell demonstrates extended reversible lithium plating/stripping over 1200 h without dendritic growth.The robust mechanical strength,excellent thermal stability,and electrochemical stability of PCNIL allow Li|PCNIL|LiFePO_(4)cells to operate stably in a wide temperature range of 25–150℃.
基金financial support of the TMA pai scholarship from the Manipal Institute of Technology,Manipal Academy of Higher Education,Manipal,in achieving this milestone。
文摘Graphitic carbon nitride(g-C_(3)N_(4)),known for its green and abundant nature and composed of carbon and nitrogen in a two-dimensional structure,has emerged as a significant area of interest across various disciplines,particularly in energy conversion and storage.Its recent demonstrations of high potential in supercapacitor applications mark it as a promising alternative to graphene within the realm of materials science.Numerous favorable features,such as chemical and thermal stability,abundant nitrogen content,eco-friendly attributes,and gentle conditions for synthesis,are shown.This review summarizes recent advancements in the use of g-C_(3)N_(4)and its composites as electrodes for supercapacitors,highlighting the advantages and issues associated with g-C_(3)N_(4)in these applications.This emphasizes situations where the composition of g-C_(3)N_(4)with other materials,such as metal oxides,metal chalcogenides,carbon materials,and conducting polymers,overcomes its limitations,leading to composite materials with improved functionalities.This review discusses the challenges that still need to be addressed and the possible future roles of g-C_(3)N_(4)in the research of advanced supercapacitor technology,such as battery-hybrid supercapacitors,flexible supercapacitors,and photo-supercapacitors.
基金supported by the National Natural Science Foundation of China(22262010,22062005,22165005,U20A20128)Guangxi Science and Technology Fund for Distinguished HighTalent Introduction Program(AC22035091)Guangxi Science Fund for Distinguished Young Scholars(2019GXNSFFA245016)。
文摘Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.
基金the China Scholarship Council for financial supportthe Max Planck Society for financial supportOpen Access funding enabled and organized by Projekt DEAL
文摘Sodium-ion capacitors(SICs)have great potential in energy storage due to their low cost,the abundance of Na,and the potential to deliver high energy and power simultaneously.This article demonstrates a template-assisted method to induce graphitic nanodomains and micro-mesopores into nitrogen-doped carbons.This study elucidates that these graphitic nanodomains are beneficial for Na+storage.The obtained N-doped carbon(As8Mg)electrode achieved a reversible capacity of 254 mA h g^(-1)at 0.1 A g^(-1).Moreover,the As8Mg-based SIC device achieves high combinations of power/energy densities(53 W kg^(-1)at 224 Wh kg^(-1)and 10410 W kg^(-1)at 51 Wh kg^(-1))with outstanding cycle stability(99.7%retention over 600 cycles at 0.2 A g^(-1)).Our findings provide insights into optimizing carbon’s microstructure to boost sodium storage in the pseudocapacitive mode.
基金the National Natural Science Foundation of China(No.52004179)the Natural Nat-ural Science Foundation of Guangxi Province,China(No.2020GXNSFAA159015)Shanxi Water and Wood New Carbon Materials Technology Co.,Ltd.,China,and Shanxi Wote Haimer New Materials Technology Co.,Ltd,China.
文摘The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl solu-tion.The as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion storage.Additionally,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).
基金the National Natural Science Foundation of China(Nos.52272046,52090030,52090031,52122301,51973191)the Natural Science Foundation of Zhejiang Province(LR23E020003)+4 种基金Shanxi-Zheda Institute of New Materials and Chemical Engineering(2021SZ-FR004,2022SZ-TD011,2022SZ-TD012,2022SZ-TD014)Hundred Talents Program of Zhejiang University(188020*194231701/113,112300+1944223R3/003,112300+1944223R3/004)the Fundamental Research Funds for the Central Universities(Nos.226-2023-00023,226-2023-00082,2021FZZX001-17,K20200060)National Key R&D Program of China(NO.2022YFA1205300,NO.2022YFA1205301,NO.2020YFF0204400,NO.2022YFF0609801)“Pioneer”and“Leading Goose”R&D Program of Zhejiang 2023C01190.
文摘Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.
基金This work was supported by the National Natural Science Foundation of China(42307566,22205084)China Postdoctoral Science Foundation(2023M742199,2023M741039)+1 种基金This project was fundedby the National&Local Joint Engineering Research Center for Mineral Salt Deep Utilization(SF202303)the State Key Laboratory of Efficient Utilization for LowGrade Phosphate Rock and Its Associated ResourcesWFKF(2023)013.
文摘Hydrogen peroxide(H_(2)O_(2))is one of the 100 most important chemicals in the world with high energy density and environmental friendliness.Compared with anthraquinone oxidation,direct synthesis of H_(2)O_(2) with hydrogen(H_(2))and oxygen(O_(2)),and electrochemical methods,photocatalysis has the characteristics of low energy consumption,easy operation and less pollution,and broad application prospects in H_(2)O_(2) generation.Various photocatalysts,such as titanium dioxide(TiO_(2)),graphitic carbon nitride(g-C_(3)N_(4)),metal-organic materials,and nonmetallic materials,have been studied for H_(2)O_(2) production.Among them,g-C_(3)N_(4) materials,which are simple to synthesize and functionalize,have attracted wide attention.The electronic band structure of g-C_(3)N_(4) shows a bandgap of 2.77 eV,a valence band maximum of 1.44 V,and a conduction band minimum of−1.33 V,which theoretically meets the requirements for hydrogen peroxide production.In comparison to semiconductor materials like TiO_(2)(3.2 eV),this material has a smaller bandgap,which results in a more efficient response to visible light.However,the photocatalytic activity of g-C_(3)N_(4) and the yield of H_(2)O_(2) were severely inhibited by the electron-hole pair with high recombination rate,low utilization rate of visible light,and poor selectivity of products.Although previous reviews also presented various strategies to improve photocatalytic H_(2)O_(2) production,they did not systematically elaborate the inherent relationship between the control strategies and their energy band structure.From this point of view,this article focuses on energy band engineering and reviews the latest research progress of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production.On this basis,a strategy to improve the H_(2)O_(2) production by g-C_(3)N_(4) photocatalysis is proposed through morphology control,crystallinity and defect,and doping,combined with other materials and other strategies.Finally,the challenges and prospects of industrialization of g-C_(3)N_(4) photocatalytic H_(2)O_(2) production are discussed and envisioned.
基金supported by the National Natural Science Foundation of China(No.62105277)the Natural Science Foundation of Henan Province(No.232300420139)+4 种基金the International Science and Technology Cooperation Program of Henan Province(No.242102520019)the Internationalization Training of High-Level Talents of Henan ProvinceNanhu Scholars Program for Young Scholars of XYNUGerman Research Foundation(DFG:LE2249/15-1)the Sino-German Center for Research Promotion(No.GZ1579)。
文摘K-ion batteries(KIBs)have drawn much attention due to the abundant potassium reserves and wide accessibility as well as high energy density,which can be designed for large-scale energy storage systems.As the most promising anode materials for KIBs,graphitic carbons,especially those with an intermediate structure between the crystalline graphite and amorphous carbons become a hot research focus because of the improved rate capability and enhanced diffusion-controlled capacity at low voltage regions.Herein,we first review the structures of graphitic carbons in the view of graphitic domains and the structure changes in their K-ion intercalation compounds.Then,we summarize the preparation mechanisms and characterizations of graphitic carbons and the influence factors in their degree of graphitization.Furtherly,we illustrate the strategies to optimize their K-ion storage properties from four aspects,namely graphitic domain design,microstructure engineering,electrochemical active component regulation,and defect engineering.Finally,we propose the issues that urgently need to be solved in graphitic carbons and the possible solutions.We hope that this view could offer some inspiration for the further designing and optimizing of graphitic carbons for practical KIBs.
文摘The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The protective properties of mild steel coated with this nanocomposite in a marine environment were assessedusing electrochemical techniques.Thermogravimetric analysis(TGA)and Cone calorimetry tests demonstrated thatGCN/EAMS-TiO_(2)significantly enhanced the flame retardancy of the epoxy coating,reducing peak heat release rate(PHRR)and total heat release(THR)values by 88%and 70%,respectively,compared to pure EP.Salt spray testsindicated reduced water absorption and improved corrosion resistance.The optimal concentration of 0.6 wt%GCNEAMS/TiO_(2)yielded the highest resistance,with the nanocomposite achieving a coating resistance of 7.50×10^(10)Ω·cm^(2)after 28 d in seawater.The surface resistance of EP-GCN/EAMS-TiO_(2)was over 99.9 times higher than pure EP after onehour in seawater.SECM analysis showed the lowest ferrous ion dissipation(1.0 nA)for EP-GCN/EAMS-TiO_(2)coatedsteel.FE-SEM and EDX analyses revealed improved breakdown products and a durable inert nanolayered covering.Thenanocomposite exhibited excellent water resistance(water contact angle of 167°)and strong mechanical properties,withadhesive strength increasing to 18.3 MPa after 28 d in seawater.EP-GCN/EAMS-TiO_(2)shows potential as a coatingmaterial for the shipping industry.
基金supported by the Dong-A University research fund.
文摘In recent years,sodium-ion batteries(SIBs)have emerged as a promising technology for energy storage systems(ESSs)because of the abundance and affordability of sodium.Recently,metal selenides have been studied as promising high-performance conversion-type anode materials in SIBs.Among them,nickel se-lenide(NiSe_(2))has received considerable attention due to its high theoretical capacity of 495 mAh g^(-1)and conductivity.However,it still suffers from poor cycling stability because of the low electrochemical reactivity,large volume expansion,and structural instability during cycles.To address these challenges,NiSe_(2)nanoparticles encapsulated in N-doped graphitic carbon fibers(NiSe_(2)@NGCF)were synthesized by using ZIF-8 as a template.NiSe_(2)@NGCF showed a high discharge capacity of 558.3 mAh g^(-1)with a fading rate of 0.14%per cycle after 200 cycles at 0.5 A g^(-1)in 0.01-3.0 V.At a very high current density of 5 A g^(-1),the capacity still displayed excellent long-term cycle life with a discharge capacity of 406.1 mAh g^(-1)with a fading rate of 0.016%per cycle after 3000 cycles.The mechanism of the excellent electrochem-ical performance of NiSe_(2)@NGCF was thoroughly investigated by ex-situ XRD,TEM,and SEM analyses.Furthermore,NiSe_(2)@NGCF//Na_(3)V_(2)(PO_(4))_(3)full-cell also delivered an excellent reversible capacity of 378.7 mAh g^(−1)at 0.1 A g^(−1)after 50 cycles,demonstrating its potential for practical application in SIBs.
基金financially supported by the National Natural Science Foundation of China(No.52100076)the Fundamental Research Funds for the Central Universities(No.2023MS064)。
文摘Covalently bonded bridging between different semiconductors is a remarkable approach to improve the transfer of charge carriers at interfaces.In this study,we designed a ternary heterojunction(MBG)combining of molybdenum diselenide(Mo Se_(2)),black phosphorus nanosheets(Bpn)and graphitic carbon nitride(GCN).Among this MBG of Mo Se_(2)/Bpn/GCN,(i)the covalently bonded bridging effect between Bpn/GCN facilitates directional charge carrier transfer,meanwhile(ii)a Z-scheme heterojunction is formed between Mo Se_(2)/GCN to enhance the separation of photogenerated carriers.Furthermore,(iii)this composite exhibits an increased absorption for visible light.Using this MBG,photocatalytic degradation of over 98%of moxifloxacin is achieved within 20 min,with O_(2)·-confirmed as the primary photocatalytic active species.These findings provide novel insights into the construction of efficient heterojunction by covalently bonded bridging.
基金financially supported by the National Natural Science Foundation of China(No.61804136,U1804155,11974317,62027816,12074348,and U2004168)Henan Science Fund for Distinguished Young Scholars(No.212300410020)+2 种基金Natural Science Foundation of Henan Province(No.212300410020 and 212300410078)Key Project of Henan Higher Education(No.21A140001)the Zhengzhou University Physics Discipline Improvement Program and China Postdoctoral Science Foundation(No.2018M630829 and 2019 T120630)
文摘Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PSDs operating at high temperatures can be found up to now.Herein,we design a new 2D/3D graphitic carbon nitride(g-C_(3)N_(4))/gallium nitride(GaN)hybrid heterojunction to construct the ultraviolet high-temperature-resistant PSD.The g-C_(3)N_(4)/GaN PSD exhibits a high position sensitivity of 355 mV mm^(-1),a rise/fall response time of 1.7/2.3 ms,and a nonlinearity of 0.5%at room temperature.The ultralow formation energy of-0.917 eV atom^(-1)has been obtained via the thermodynamic phase stability calculations,which endows g-C_(3)N_(4)with robust stability against heat.By merits of the strong built-in electric field of the 2D/3D hybrid heterojunction and robust thermo-stability of g-C_(3)N_(4),the g-C_(3)N_(4)/GaN PSD delivers an excellent position sensitivity and angle detection nonlinearity of 315 mV mm^(-1)and 1.4%,respectively,with high repeatability at a high temperature up to 700 K,outperforming most of the other counterparts and even commercial silicon-based devices.This work unveils the high-temperature PSD,and pioneers a new path to constructing g-C_(3)N_(4)-based harsh-environment-tolerant optoelectronic devices.
文摘Graphitic carbon nitride with nanorod structure(Nr-GCN)was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment method.XRD,FTIR,SEM,N_(2)adsorption-desorption from BET,UV-Vis DRS spectroscopy,and photoluminescence were used to characterize the prepared samples.Also,the photoelectrochemical behavior of nanoparticles was studied by photocurrent transient response and cyclic voltammetry analysis.Polystyrene(PS)fibrous mat was fabricated by electrospinning technique and used as a support for the stabilization of the nanoparticles.The performance of the synthesized nanoparticles and photocatalytic fibers(PS/Nr-GCN)was evaluated in oilfield-produced water treatment under visible light irradiation.During this process,oil contaminants were adsorbed by hydrophobic polystyrene fibers and simultaneously degraded by Nr-GCN.The removal efficiency of chemical oxygen demand(COD)has been obtained 96.6%and 98.4%by Nr-GCN and PS/Nr-GCN,respectively,at the optimum conditions of pH4,photocatalyst dosage 0.5 g/L,COD initial concentration 550 mg/L,and illumination time 150 min.The gas chromatography-mass spectroscopy analysis results showed 99.3%removal of total petroleum hydrocarbons using photocatalytic fibers of PS/Nr-GCN.The results demonstrated that the GCN has outstanding features like controllable morphology,visible-light-driven,and showing high potential in oily wastewater remediation.Moreover,the synergistic effect of adsorption and photocatalytic degradation is an effective technique in oilfield-produced water treatment.
基金supported by the National Basic Research Program of China(2011CB933700)the National Natural Science Foundation of China(21271165)~~
文摘With the objectives of enhancing the stability,optical properties and visible-light photocatalytic activity of photocatalysts,we modified oxygen vacancy-rich zinc oxide（Vo-ZnO） with graphitic carbon nitride（g-C3N4）. The resulting g-C3N4/Vo-ZnO hybrid photocatalysts showed higher visible-light photocatalytic activity than pure Vo-ZnO and g-C3N4. The hybrid photocatalyst with a g-C3N4 content of 1 wt% exhibited the highest photocatalytic degradation activity under visible-light irradiation（λ≥ 400 nm）. In addition,the g-C3N4/Vo-ZnO photocatalyst was not deactivated after five cycles of methyl orange degradation,indicating that it is stable under light irradiation. Finally,a Z-scheme mechanism for the enhanced photocatalytic activity and stability of the g-C3N4/Vo-ZnO hybrid photocatalyst was proposed. The fast charge separation and transport within the g-C3N4/Vo-ZnO hybrid photocatalyst were attributed as the origins of its enhanced photocatalytic performance.
基金supported by the Natural Science Foundation of China(NSFC Grant No.20803064)the Natural Science Foundation of Zhejiang Provence(Y4090348 and LY12B03007)Qianjiang Talent Project in Zhejiang Province(2010R10039 and 2013R10056)
文摘A series of high surface area graphitic carbon materials （HSGCs） were prepared by ball-milling method. Effect of the graphitic degree of HSGCs on the catalytic performance of Ba-Ru-K/HSGC-x （x is the ball-milling time in hour） catalysts was studied using ammonia synthesis as a probe reaction. The graphitic degree and pore structure of HSGC-x supports could be successfully tuned via the variation of ball-milling time. Ru nanoparticles of different Ba-Ru-K/HSGC-x catalysts are homogeneously distributed on the supports with the particle sizes ranging from 1.6 to 2.0 nm. The graphitic degree of the support is closely related to its facile electron transfer capability and so plays an important role in improving the intrinsic catalytic performance of Ba-Ru-K/HSGC-x catalyst.
基金National Natural Science Foundation of China,Grant/Award Number:51777138Deutsche Forschungsgemeinschaft(DFG,German Research Foundation),Grant/Award Number:491183248Open Access Publishing Fund of the University of Bayreuth。
文摘N-doped carbons as one of the most prominent anode materials to replace standard graphite exhibit outstanding Li+storage performance.However,N-doped carbon anodes still suffer from low N-doping levels and low initial Coulombic efficiency(ICE).In this study,high N-doped and low graphitic-N carbons(LGNCs)with enhanced ICE were synthesized by taking advantage of a denitrification strategy for graphitic carbon nitride(g-C_(3)N_(4)).In brief,more than 14.5 at%of N from g-C_(3)N_(4)(55.1 at%N)was retained by reacting graphitic-N with lithium,which was subsequently removed.As graphitic-N is largely responsible for the irreversible capacity,the anode's performance was significantly increased.Compared to general N-doped carbons with high graphitic-N proportion(>50%)and low N content(<15 at%),LGNCs delivered a low proportion of 10.8%-17.2% within the high N-doping content of 14.5-42.7 at%,leading to an enhanced specific capacity of 1499.9mAh g^(-1) at an ICE of 93.7% for the optimal sample of LGNC(4:1).This study provides a facile strategy to control the N content and speciation,achieving both high Li+storage capacity and high ICE,and thus promoting research and application of N-doped carbon materials.
基金supported by the National Program on Key Basic Research Project (2016YFA0203000)the Early Career Scheme (ECS 809813) from the Research Grant Council, Hong Kong SAR Government+2 种基金the Croucher Foundation Visitorship for PRC Scholars 2015/16 at The Education University of Hong Kongthe National Natural Science Foundation of China (51672312, 21373275)the Program for New Century Excellent Talents in University (NCET-12-0668)~~
文摘Pure bismuth（Bi） metal-modified graphitic carbon nitride（g-C3N4） composites（Bi-CN） with a pomegranate-like structure were prepared by an in situ method.The Bi-CN composites were used as photocatalysts for the oxidation of nitric oxide（NO） under visible-light irradiation.The inclusion of pure Bi metal in the g-C3N4 layers markedly improved the light absorption of the Bi-CN composites from the ultraviolet to the near-infrared region because of the typical surface plasmon resonance of Bi metal.The separation and transfer of photogenerated charge carriers were greatly accelerated by the presence of built-in Mott-Schottky effects at the interface between Bi metal and g-C3N4.As a result,the Bi-CN composite photocatalysts exhibited considerably enhanced efficiency in the photocatalytic removal of NO compared with that of Bi metal or g-C3N4 alone.The pomegranate-like structure of the Bi-CN composites and an explanation for their improved photocatalytic activity were proposed.This work not only provides a design for highly efficient g-C3N4-based photocatalysts through modification with Bi metal,but also offers new insights into the mechanistic understanding of g-C3N4-based photo catalysis.
基金supported by Xiamen University Malaysia Research Fund (XMUMRF/2019-C3/IENG/0013)financial assistance and faculty start-up grants/supports from Xiamen University~~
文摘As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.
