Two-dimensional Graphitic Carbon Nitride Research Articles

Pt nanoparticles embedded spine-like g-C3N4 nanostructures with superior photocatalytic activity for H2 generation and CO2 reduction

Conventional two-dimensional (2D) graphitic carbon nitride, 2D g-C3N4 with its layered structures and flat and smooth 2D surface possesses certain disadvantages that is affecting their photocatalytic performances. In this paper, new nanostructured spine-like three-dimensional (3D) g-C3N4 nanostructures are created for the first time via a new three-step synthesis method. In this method, self-assembly of layered precursors and H+ intercalation introduced by acid treatment play an important role for the unique nanostructure formation of 3D g-C3N4 nanostructures. The spine-like 3D g-C3N4 nanostructures show a superior photocatalytic performance for H2 generation, achieving 4500 μmol·g−1·h−1, 8.2 times higher than that on conventional 2D g-C3N4. Remarkably spine-like 3D g-C3N4 nanostructures demonstrate a clear photocatalytic activity toward CO2 reduction to CH4 (0.71 μmol·g−1·h−1) in contrast to the negligible photocatalytic performance of conventional 2D g-C3N4 for the reaction. Adding Pt clusters as co-catalysts substantially enhance the CH4 generation rate of the 3D g-C3N4 nanostructures by 4 times (2.7 μmol·g−1·h−1). Spine-like 3D g-C3N4 caged nanostructure leads to the significantly increased active sites and negatively shifted conduction band position in comparison with conventional 2D g-C3N4, favorable for the photocatalytic reduction reaction. This study demonstrates a new platform for the development of efficient photocatalysts based on nanostructured 3D g-C3N4 for H2 generation and conversion of CO2 to useful fuels such as CH4.

Molecular Mechanism for the Self-Supported Synthesis of Graphitic Carbon Nitride from Urea Pyrolysis.

Quantum chemical calculations combined with kinetic Monte Carlo simulations are performed to decipher the kinetics for the one-pot synthesis of two-dimensional graphitic carbon nitride (g-C3N4) from urea pyrolysis. Two mechanisms are considered, one involving ammelide as the intermediate compound and the other considering cyanuric acid. Different grid growing patterns are investigated, and the size, shape, and density of the grids as well as the number and position of the defects are evaluated. We find that the mechanistic pathway involving ammelide is preferred. Larger g-C3N4 grids with lower density are achieved when the rate constant for melon growing is inversely proportional to the number of local reaction sites, while nearly filled smaller grids are obtained in the opposite scenario. Larger defects appear at the grid periphery while smaller holes appear throughout the grid. The synthesis of extended g-C3N4 structures is favored if the g-C3N4 growing propensity is directly proportional to the number of reaction sites.

Plasmonic photo-assisted electrochemical sensor for detection of trace lead ions based on Au anchored on two-dimensional g-C3N4/graphene nanosheets

In this paper, a plasmonic photo-assisted electrochemical sensor, Au anchored on two-dimensional (2D) graphitic carbon nitride (g-C3N4)/reduced graphene oxide (rGO) nanosheets (Au/g-C3N4/rGO), was facile fabricated. The morphology and structure of the composite are characterized by transmission electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction and ultraviolet–visible spectrophotometer (UV–Vis). Based on the semiconductor of g-C3N4 and optical properties of surface plasmon resonance for Au, the as-prepared Au/g-C3N4/rGO showed high sensitivity for the detection of trace lead ion [Pb(II)] by differential pulse anodic stripping voltammetry in the presence of visible light illumination. Under optimized conditions, the limit of detection (signal-to-noise ratio (S/N) = 3) Pb(II) detection can be low to 0.1 nmol·L−1. In addition, the interference research and real soil sample detection were measured to confirm the possibility of practical applications.

Effect of a novel one-dimensional zinc tungsten oxide nanorods anchored two-dimensional graphitic carbon nitride nanosheets for improved solar-light-driven photocatalytic removal of toxic pollutants and photoelectrochemical water splitting

In this study, one-dimensional zinc tungsten oxide (ZnWO4) was prepared by a simple hydrothermal procedure, and two-dimensional graphitic carbon nitride (g-C3N4) was prepared by a solid-state reaction method. The g-C3N4/ZnWO4 (CZO) heterostructure was prepared by a hydrothermal approach. Further, TEM, HRTEM, XRD, DRS, and electrochemical investigations were used to describe the formation of CZO heterostructure. The photocatalytic performance of a CZO nanocomposite shows promising properties for the degradation of tetracycline (TC). Further, the CZO nanocomposite was also used for the photoelectrochemical (PEC) water oxidation. The morphology and structural analysis demonstrated the successful dispersion of ZnWO4 nanorods over the g-C3N4 nanosheets. The tuning of CZO nanocomposite bandgap confirms the establishment of heterostructure. From the photocatalytic investigations, the CZO nanocomposite degrades the antibiotic TC within 70 min under solar-light irradiation. The detailed PEC investigations notify the CZO nanocomposite has lesser charge-transfer resistance, high response of photocurrent with good stability. The CZO electrolyte shows improved photocurrent density of 0.162 mA/cm2 vs. Ag/AgCl in 0.1 M Na2SO3 electrolyte under solar-light illumination. The detailed mechanisms of photocatalytic degradation of TC and PEC water oxidation were discussed with possible graphical diagrams.

Efficiently harvesting the ultrasonic vibration energy of two-dimensional graphitic carbon nitride for piezocatalytic degradation of dichlorophenols

The ultrasound-induced piezoelectric field drives electrons and holes to migrate in opposite directions towards the surface of 2D g-C3N4, leading to the formation of active species, which further degrade dichlorophenols into small molecules.

New structure candidates for the experimentally synthesized heptazine-based and triazine-based two dimensional graphitic carbon nitride

The widely used crystal structures for both heptazine-based and triazine-based two-dimensional (2D) graphitic carbon nitride (g-C 3 N 4 ) are the flat P-6m2 configurations. However, the experimentally synthesized 2D g-C 3 N 4 possess thickness ranging in 0.2–0.5 nm, indicating that the theoretically used flat P-6m2 configurations are not the correct ground states. In this work, we propose three new corrugated structures P321, P3m1 and Pca21 with energies of 66 (86), 77 (87) and 78 (89) meV/atom lower than that of the corresponding heptazine-based (triazine-based) g-C 3 N 4 in flat P-6m2 configuration, respectively. These corrugated structures have very similar periodic patterns to the flat P-6m2 ones and they are difficult to be distinguished from each other according to their top-views. The optimized thicknesses of the three corrugated structures ranging in 1.347–3.142 Å are in good agreement with the experimental results. The first-principles results show that these corrugated structural candidates are also semiconductors with band gaps larger than those of the correspondingly flat P-6m2 ones. Furthermore, they possess also suitable band edge positions for sun-light-driven water-splitting at both pH = 0 and pH = 7 environments. Our results show that these three new structures are more promising candidates for the experimentally synthesized g-C 3 N 4 . • Three low-energy and corrugated structures P321, P3m1 and Pca21 for graphic C 3 N 4 . • Structural candidates for the experimentally synthesized two-dimensional graphic C 3 N 4 . • Proper band-edge positions for applications in sun-light-driven water-splitting.

Lanthanum ions decorated 2-dimensional g-C3N4 for ciprofloxacin photodegradation

The low band gap energy and high surface area two-dimensional materials allow it to tune its basic properties using surface decoration. Here, La3+ are decorated on two-dimensional graphitic carbon nitride using a simple and easily scalable chemisorption process with an adsorption capacity of 657.32 mg g−1. In the X-ray diffraction (XRD) study, the positive slope of the W–H plot elucidates the tensile strain generation (0.103) in La3+ ions decorated 2D-g-C3N4 (La3+-2D-g-C3N4). The high-resolution transmission electron microscope (HR-TEM) study and the higher ID/IG ratio (0.82) in the Raman spectroscopy study confirm the more defects intensification in La3+-2D-g-C3N4. The reduction in band gap energy for La3+-2D-g-C3N4 (from 2.83 eV to 2.21 eV) has shown a good correspondence with the band structures study as obtained from the DFT study. In the DFT study, the significant contributions of N atoms in charge transfer validate the N 1s findings from the X-ray photoelectron spectroscopy (XPS) study for La3+-2D-g-C3N4. La3+-2D-g-C3N4 shows the photodegradation efficiency (93%) of ciprofloxacin under UV irradiation, which is superior to pristine 2D-g-C3N4 (82%) as well as other g-C3N4 based nanocatalysts. Also, La3+ decoration results in enhancement (32.3%) in photodegradation kinetics rate. The degradation and kinetics studies in the presence of different scavengers ensure that the O2ˉ and OH− radicals are mostly responsible for the ciprofloxacin photodegradation. The Liquid chromatographic-mass spectroscopy and the high-performance liquid chromatography studies confirm the photodegradation. The reusability of La3+-2D-g-C3N4 is tested up to the fifth cycle. FTIR and UV–visible absorption spectroscopy confirm the stability of the used photocatalyst.

Large-scale production of ultrathin carbon nitride-based photocatalysts for high-yield hydrogen evolution

Although two-dimensional graphitic carbon nitride (2D g-C3N4) and corresponding heterostructures have been widely synthesized for photocatalysis, it is still challenging to obtain 2D g-C3N4 at large-scale and also achieve high quantum efficiency. Here we report a subtractive manufacturing method mediated by Nb2O5 to mass-produce high quality Nb2O5/2D g-C3N4 and pure 2D g-C3N4. Nb2O5/2D g-C3N4 and 2D g-C3N4 both show efficient photocatalytic hydrogen evolution performance, in which the optimal Nb2O5/2D g-C3N4 exhibits high external quantum efficiency (50.65 % and 14.75 % at 405 nm and 420 nm). The origin of the high efficiency can be ascribed to two aspects: (i) nanostructure engineering forming 2D structure can shorten the charge migration distance; (ii) Nb2O5/2D g-C3N4 with strong electric coupling can further accelerate the charge transfer driven by the built-in electric field formed in Type II heterostructure. This work presents a case study to realize high-yield synthesis and high catalytic performance simultaneously over g-C3N4.

Two dimensional Cu based nanocomposite materials for direct urea fuel cell

In this work, Cu2O nanoparticles were successfully prepared onto the surface of two-dimensional graphitic carbon nitride (g-C3N4) by using a simple solution chemistry approach. An environment-friendly reducing agent, glucose, was used for the synthesis of Cu2O NPs onto the surface of g-C3N4 without using any surfactant or additives. The surface composition, crystalline structure, morphology, as well as other properties have been investigated using XPS, XRD, SEM, FTIR, FESEM, EDS, etc. The electrochemical measurements of the prepared materials demonstrated that Cu2O exhibited a weak oxidation activity towards urea, while g-C3N4 has no activity towards urea oxidation. The Cu2O supported on the surface of g-C3N4 (Cu2O-g-C3N4) demonstrated a significant activity towards urea oxidation that reached two times that of the unsupported one. The significant increase in the performance was related to the synergetic effect between the Cu2O and g-C3N4 support. The prepared composite materials demonstrated high stability towards urea oxidation as confirmed from the stable current discharge for around 3 h without any noticeable degradation performance.

Delicate Balance of Non-Covalent Forces Govern the Biocompatibility of Graphitic Carbon Nitride towards Genetic Materials.

Despite a plethora of suggested technological and biomedical applications, the nanotoxicity of two-dimensional (2D) graphitic carbon nitride (g-C3 N4 ) towards biomolecules remains elusive. To address this issue, we employ all-atom classical molecular dynamics simulations and investigate the interactions between nucleic acids and g-C3 N4 . It is revealed that, toxicity is modulated through a subtle balance between electrostatic and van der Waals interactions. When the exposed nucleobases interact through predominantly short-ranged van der Waals and π-π stacking interactions, they get deviated from their native disposition and adsorb on the surface, leading to loss of self-stacking and intra-quartet H-bonding along with partial disruption of the native structure. In contrast, for the interaction with double-stranded structures of both DNA and RNA, long-range electrostatics govern the adsorption phenomena since the constituent nucleobases are relatively concealed and wrapped, thereby resulting in almost complete preservation of the nucleic acid structures. Construction of free energy landscapes for lateral translation of adsorbed nucleic acids suggests decent targeting specificity owing to their restricted movement on g-C3 N4 . The release times of nucleic acids adsorbed through predominant electrostatics are significantly less than those adsorbed through stacking with the surface. It is therefore proposed that g-C3 N4 would induce toxicity towards any biomolecule having bare residues available for strong van der Waals and π-π stacking interactions relative to those predominantly interacting through electrostatics.

Self-powered flexible photodetectors based on Ag nanoparticle-loaded g-C3N4 nanosheets and PVDF hybrids: role of plasmonic and piezoelectric effects

Here we demonstrate novel self-powered photodetection using silver (Ag) nanoparticle-loaded two-dimensional graphitic carbon nitride (g-C3N4) nanosheets triggered by poly-vinylidene fluoride (PVDF)-based flexible piezoelectric nanogenerators. A self-poled PVDF-based nanogenerator has been obtained upon exploiting pristine g-C3N4 nanosheets as a filler material within the PVDF matrix. The fabricated nanogenerator devices are found to be highly efficient in generating the maximum voltage of ∼2.3 V and maximum power ∼110 μWatt/cm2, upon finger tapping. Further, the integration of an additional layer of plasmonic Ag nanoparticle-loaded g-C3N4 nanosheets, has led to a significant enhancement of photoresponse. The hybrid plasmonic nanogenerator (with a strain of ∼0.021%) has resulted in self-powered photodetection with a photo-to-dark current ratio of ∼60, as compared to the unstrained device (∼2.0). In contrast to the usual behaviour (positive photoresponse), the exposure of an ultraviolet light lowers the output current indicating a negative photoresponse reported for the first time in such a system. The origin of such negative photoresponse has been attributed to the screening of piezopotential of PVDF by photogenerated carriers of g-C3N4 nanosheets. On the other hand, visible light-induced positive photoresponse has originated from the increment in the current, indicating the useful role of Ag nanoparticles in plasmon-induced hot electron transfer process.

1D/2D C3N4/Graphene Composite as a Preferred Anode Material for Lithium Ion Batteries: Importance of Heterostructure Design via DFT Computation.

Graphene is commonly used to improve the electrochemical performance of electrode materials in rechargeable batteries by forming graphene-based heterostructures. Two-dimensional graphitic carbon nitride (C3N4) is an analogue of graphene, and it is often used to form 1D/2D and 2D/2D C3N4/graphene heterostructures. However, a theoretical understanding of the heterointerface in these heterostructures and how this affects their electrochemical performance is lacking. In this work we study the heterointerface of 1D/2D and 2D/2D C3N4/graphene heterostructures and how the different dimensions influence the lithium ion battery performance of the heterostructure. Our density functional theory (DFT) study showed that the common problem of C-N bond breakage experienced in 2D/2D C3N4/graphene heterostructure does not occur in the 1D/2D heterostructure. Furthermore, the 1D/2D heterostructure showed superior conductivity in comparison to that of the 2D/2D heterostructure of C3N4/graphene. The 1D/2D C3N4/graphene heterostructure also recorded a high theoretical capacity and rapid charge transfer. These results suggest that the properties of a heterostructure are influenced by the dimension of materials at the interface. These discoveries on the relationship between material dimension in heterostructure electrodes and their electrochemical performance will motivate the design of advanced electrode materials for rechargeable batteries.

Photocatalytic dye degradation under sunlight irradiation using cerium ion adsorbed two-dimensional graphitic carbon nitride

• Adsorption experiments and DFT simulation study suggest the chemisorption of Ce 3+ on 2D-g-C 3 N 4 . • HR-TEM image shows the localized point defects and lattice alteration of Ce 3+ -g-C 3 N 4 . • Experimental observations (HR-TEM/FTIR/XPS) are in well correspondence with simulated results. • Ce 3+ -g-C 3 N 4 delays the recombination probability of photogenerated charge carriers and increases the fluorescence decay time. • Optimized Ce 3+ -g-C 3 N 4 shows dye degradation efficiency upto 95 % in water under sunlight irradiation. Unique optical, physicochemical and surface properties of two dimensional (2D) materials provide an enormous opportunity in environmental remediation. Those properties are further tuned by using external dopant or alloying elements. Due to their distinct optoelectronics properties, the rare earth elements and compounds act as a proficient dopant in combination with 2D materials. Here, 2D-g-C 3 N 4 accumulated with Ce 3+ (Ce 3+ -g-C 3 N 4 ) has been synthesized using simple and easily scalable ion-adsorption (chemical controlled) process. The spectroscopy and microscopy techniques have been utilized to understand the surface adsorption, optical properties and localized point defect formation due to decoration of Ce 3+ . Along with the experimental studies, first principles density functional theory (DFT) calculations have been performed to understand the structural and electronic behavior of Ce 3+ adsorption on 2D-g-C 3 N 4 . Ce 3+ -g-C 3 N 4 prepared using optimized condition is further utilized for removal of a pollutant, namely methylene blue dye from the water with 95 % efficiency even under sunlight. Also, Ce 3+ -g-C 3 N 4 shows an enhancement in photocatalytic degradation rate (∼20 %) as compared to 2D-g-C 3 N 4 . So the suggested photocatalyst can be used commercially in the field of pollutant degradation.

Two-dimensional graphitic carbon nitrides: Strain-tunable ferromagnetic ordering

Using first-principle calculations, we systematically study strain tuning of the electronic properties of two-dimensional graphitic carbon nitride nanosheets with empirical formula ${C}_{n}{N}_{m}$. We found the following: (i) the ferromagnetic ordered state in the metal-free systems $(n,m)=(4,3)$, (10,9), and (14,12) remains stable in the presence of strain of about $6%$. However, the system (9,7) loses its ferromagnetic ordering when increasing strain. This is due to the presence of topological defects in the (9,7) system, which eliminates the asymmetry between spin up and spin down of the ${p}_{z}$ orbitals when strain is applied. (ii) By applying uniaxial strain, a band gap opens in systems which are initially gapless. (iii) In semiconducting systems which have an initial gap of about 1 eV, the band gap is closed with applying uniaxial strain.

Synthesis of Sulfur-Doped 2D Graphitic Carbon Nitride Nanosheets for Efficient Photocatalytic Degradation of Phenol and Hydrogen Evolution.

Sulfur-doped two-dimensional (2D) graphitic carbon nitride nanosheets (2D-SCN) with efficient photocatalytic activity were synthesized via (1) polycondensation of thiourea to form bulk sulfur-doped graphitic carbon nitride (SCN) and (2) followed by thermal oxidative treatment of the prepared SCN via an etching strategy to form 2D-SCN. Sulfur was doped in situ into SCN by using thiourea as the precursor, and the 2D nanosheet structure was obtained during the thermal oxidative etching process. The structural, morphological, and optical properties of the 2D-SCN sample were investigated in detail. Herein, it is shown that the thermal oxidative etching treatment and sulfur doping induced a 2D nanosheet structure (2D-SCN-3h) with a thickness of about 4.0 nm and exposure of more sulfur elements on the surface. The surface area increased from 16.6 m2/g for SCN to 226.9 m2/g. Compared to bulk SCN, a blue shift of the absorption peaks was observed for the obtained 2D-SCN-3h photocatalyst, and the absorption intensity was higher than that of the sulfur-free counterpart (2D-CN). The successful in situ doping of S element into SCN or 2D-SCN-3h samples is beneficial to the introduction of surface N defects and O species. 2D-SCN-3h indicated higher efficiency in photogenerated charge carrier separation and showed the highest reductive activity in photocatalytic splitting of water at a rate of 127.4 μmol/h under simulated solar light irradiation, which was 250 times and 3 times higher than that of SCN and 2D-CN photocatalysts, respectively. The apparent quantum efficiency was estimated to be 8.35% at 420 nm irradiation. The S-C-N bond formed by sulfur doping was beneficial to the charge-transfer process, and this led to higher photocatalytic activity according to partial density of state analysis computed by first-principles methods.

Post-annealed graphite carbon nitride nanoplates obtained by sugar-assisted exfoliation with improved visible-light photocatalytic performance

Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanoplates (CNNP) have become a hot research topic in photocatalysis due to their small thickness and large specific surface area that favors charge transport and catalytic surface reactions. However, the wide application of 2D g-C3N4 nanoplates prepared by ordinary methods suffers from increased band gaps with a poor solar harvesting capability caused by the strong quantum confinement effect and reduced conjugation distance. In this paper, a facile approach of exfoliation and the following fast thermal treatment of the bulk g-C3N4 is proposed to obtain a porous few-layered g-C3N4 with nitrogen defects. Due to the preferable crystal, textural, optical and electronic structures, the as-obtained porous CNNP demonstrated a significantly improved photocatalytic activity towards water splitting than the bulk g-C3N4 and even the 3 nm-thick CNNP obtained by sugar-assisted exfoliation of the bulk g-C3N4. The difference in the enhancement factors between the H2O splitting and organic decomposition has revealed the effect of N defects. This study offers insightful outlooks on the scalable fabrication of a porous few-layered structure with a promoted photocatalytic performance.

Electrochemical sensor based on anelectrode modified withporous graphitic carbon nitride nanosheets(C3N4)embedded in graphene oxidefor simultaneous determination of ascorbic acid, dopamine and uric acid.

Two-dimensional porous graphitic carbon nitride (g-C3N4) nanosheets were synthesized by low-cost and direct thermal oxidation. Porous g-C3N4 assembled with graphene oxide (GO) was immobilized ona glassy carbon electrode. The sensor was applied to simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) with high performance. Cyclic voltammetry and differential pulse voltammetry were used to investigate electrochemical and electrocatalytic properties. The results indicate that the electrochemical sensor possesses high specific surface area, hierarchical pore structure and excellent signal response to AA, DA and UA. The oxidation potentials are well separated at around 0.15, 0.34 and 0.46V for AA, DA and UA respectively. The determination limits for AA, DA and UA are 3.7μM, 0.07μM and 0.43μM, respectively. The sensor was applied to tracking the three analytes in spiked serum samples with recovery 95.1~105.5% and relation standard deviations of less than 5%. Graphical abstract Schematic representation of porous graphitic carbon nitride nanosheet embedded in graphene oxide for simultaneous determination of ascorbic acid, dopamine and uric acid.

Two-dimensional graphitic carbon nitride (g-C4N3) for superior selectivity of multiple toxic gases (CO, NO2, and NH3)

Using first principles calculations, we investigated the possibility of selecting multiple toxic gases using one substrate material. Here, we explored the transport property of H2, N2, O2, CO, CO2, NO2, and NH3 gas molecules on two-dimensional graphitic carbon nitride (2D g-C4N3). The homonuclear molecule such as H2, N2, and O2 has very weak adsorption energy (equal to or less than 0.1 eV) and also CO2 has an adsorption energy of 0.23 eV. In the typical toxic gas molecule adsorption systems, we found an appreciable charge transfer. In CO and NH3 adsorption systems, the charge transfer of 0.397 and 0.418 electrons from the molecule to the substrate was found, while the NO2 molecule gained 0.124 electrons from the substrate. Due to this large amount of charge transfer, we obtained large adsorption energies of 4.57, 1.29, and 1.93 eV in CO, NO2, and NH3 systems. Moreover, through the I–V curve calculations, we found large difference in the current. The calculated current was 21, 13.11, and 16.16 μA for CO, NO2, and NH3 systems at the bias voltage of 0.5 V. Our results imply that the 2D g-C4N3 can be a superior substrate material for sensing of multiple toxic gases.

Defect Engineering in Two-dimensional Graphitic Carbon Nitride and Application to Photocatalytic Air Purification

Defect Engineering in Two-dimensional Graphitic Carbon Nitride and Application to Photocatalytic Air Purification

Two-dimensional graphitic carbon nitride nanosheets: a novel platform for flexible, robust and optically active triboelectric nanogenerators.

We report on the characteristics of mechanically flexible, stable and photoactive triboelectric nanogenerators based on two-dimensional graphitic carbon nitride (g-C3N4) nanosheets. The performance of nanogenerator devices has been studied with varying frictional surfaces (such as polypropylene, aluminium oxide, Teflon and polyethylene terephthalate). Energy band diagrams have been used to explain the mechanism of triboelectric charge transfer in pristine and doped g-C3N4, with the former showing better characteristics. An optimized device has been found to be responsive to external stimuli to generate an output voltage of 10 V upon simple biomechanical impulses. To demonstrate the efficacy for practical applications of g-C3N4-based triboelectric nanogenerators, output voltages have been recorded for different common activities like walking, water showering, using as a writing/drawing pad, etc. Repetitive finger tapping on a device could charge a capacitor to as high as 55 V within ∼50 s, while that under UV illumination is found to be much faster (∼14 s) due to photoinduced carrier generations in g-C3N4. The exhibition of a superior photoresponsivity of ∼117 V W-1 under UV illumination demonstrates the dual functionality of g-C3N4-based triboelectric devices as a nanogenerator as well as an active flexible photosensor, which is hitherto unreported. Excellent mechanical flexibility, stability and photoinduced enhancement of output characteristics make g-C3N4 an attractive candidate for nanogenerator devices for future applications.