Graphitic Carbon Nitride Nanosheets Research Articles

Strong Interfacial Chemical Bonding in Regulating Electron Transfer and Stabilizing Catalytic Sites in a Metal-Semiconductor Schottky Junction for Enhanced Photocatalysis.

The weak electronic interaction at metal-photocatalyst heterointerfaces often compromises solar-to-fuel performance. Here, a trifunctional Schottky junction, involving chemically stabilized ultrafine platinum nanoparticles (Pt NPs, ≈3nm in diameter) on graphitic carbon nitride nanosheets (CNs) is proposed. The Pt-CN electronic interaction induces a 1.5% lattice compressive strain in Pt NPs and maintains their ultrafine size, effectively preventing their aggregation during photocatalytic reactions. Density functional theory calculations further demonstrate a significant reduction in the Schottky barrier at the chemically bonded CN-Pt heterointerface, facilitating efficient interfacial electron transfer, as supported by femtosecond transient absorption spectra (fs-TAS) measurements. The combined effects of lattice strain, stabilized Pt NPs, and efficient interfacial charge transport collaboratively enhance the photocatalytic performance, leading to over an 11-fold enhancement in visible light H2 production (8.52mmolg-1 h-1 ) compared to the CN nanosheets with the in situ photo-deposited Pt NPs (0.76mmolg-1 h-1 ). This study highlights the effectiveness of strong metal-semiconductor electronic interactions and underscores the potential for developing high-efficiency photocatalysts.

Graphitic carbon nitride supported trimeric metal clusters as electrocatalysts for N2 reduction reaction

As a cleaner and more energy-efficient alternative, the electrochemical reduction of N2 to NH3 under mild conditions has emerged as a promising avenue for environmental protection. However, developing catalysts with both high activity and selectivity has been a challenging task. The advent of atomically dispersed catalysts is revolutionizing the field of catalysis. Drawing inspiration from the successful fabrication of Ru trimer on graphitic carbon nitride (g-C3N4) nanosheets, herein, we adopted a series of trimeric metal clusters anchored on g-C3N4 monolayer (TM3@g-C3N4, TM = 3d, 4d and 5d transition metal atom), as well as utilized the criteria range to describe the stability, activity, energy cost and selectivity of supported trimers for N2 reduction reaction based on ab initio calculations combined with multi-level screening strategies. Finally, 5 candidate TM3@g-C3N4 (TM = Rh, Ru, V, Mo, and Re) exhibits decent catalytic activity with limiting potential ranging of –0.50 – –0.02 V. These spatially confined triatomic metal centers demonstrated proficiency in activating N2 molecules while exhibiting tunable surficial reactivity through modulation of the metal elements and interfacial electron coupling between trimers and underlying substrates. More importantly, a structure–activity relationship was established, which provides crucial insights for precise design of highly efficient atomically-precise catalysts at an atomic level for hydrogen fuel storage.

Zn(II)-MOFs nanosheets interaction with P-doped graphitic carbon nitride nanosheets for effective overall water splitting in alkaline medium

We developed an electrocatalyst made up of two dimensional nanosheets interacted with another two-dimensional nanosheets (2D-2D) to explore the mediation of overall water splitting in alkaline medium. The 2D-2D electrocatalyst is denoted as ZIF-P-GCN nanosheets derived from metal organic frameworks (MOFs) such as zinc coordinated imidazole framework (ZIF-8) nanosheets interacted with optimized phosphorous doped graphitic carbon nitride (P-GCN) nanosheets. The developed electrocatalyst exhibits high efficiency for oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and overall water splitting. Initially, the electrocatalyst was studied using FT-IR spectra, XRD patterns, XPS analysis, BET surface area studies, FE-SEM and HR-TEM analyses to understand its structural and morphological properties. Moreover, the synthesized ZIF-P-GCN nanosheets are porous in nature, thereby subsequently, its electrocatalytic activity has been investigated. Compared to ZIF-8 or P-GCN nanosheets, the prepared 2D-2D interacted ZIF-P-GCN nanosheets loaded on the GCE electrode showed excellent and stable electrocatalytic performance with a low overpotential of 290 and 200 mV for OER and HER, respectively, to reach the current density of 10 mA cm−2 in alkaline medium. Besides, low Tafel slope values are observed such as 30.26 mV Dec-1 for OER and 46.53 mV Dec-1 for HER, respectively, in 3 M KOH. Furthermore, a complete electrochemical cell was constructed using ZIF-P-GCN//ZIF-P-GCN nanosheets loaded Ni foam electrodes for overall water splitting to achieve a minimum cell voltage of 1.61 V at a current density of 10 mA cm−2, which is comparable to standard Pt/C//RuO2 cell system. Thus, the work attempts to develop an effective and stable 2D-2D interacted bifunctional electrocatalyst for overall water splitting using a novel and easy route.

Enhancing Cd(II) and U(VI) remediation through synergistic utilization of GCN-supported MgFe-layered double hydroxide

Due to the significant concentration of heavy metals in the contaminated area, it presents an imminent threat to both living organisms and the environment. In this research, we concentrate on finding an effective solution for eliminating Cd(II) and U(VI) from water. Our approach involves utilizing MgFe-layered double hydroxide (LDH) nanosheets combined with graphitic carbon nitride (GCN) nanosheets to ensure the effective elimination of these hazardous metal ions. The characterization techniques, including SEM, XPS, XRD, and BET analysis, confirmed the hierarchical layered structure of GCN/MgFe LDH with a significant surface area of 127.91 m2/g. Batch investigations demonstrated that the pH of the solution influences the elimination of both metal ions, while kinetics and equilibrium data well align with a pseudo-second-order model and the Langmuir model (R2 = 0.996–1.0), respectively. GCN/MgFe LDH demonstrated impressive removal capacities of 312.30 mg/g and 273.42 mg/g for Cd(II) and U(VI) respectively. A thermodynamic analysis indicated that the adsorption process of both metal ions was endothermic and spontaneous. Furthermore, the GCN/MgFe LDH can be reused for over five cycles. In the fourth cycle, it maintained a removal percentage of over 95 % for both metal ions when 0.1 M HNO3 was used for desorption. In continuous column tests, the GCN/MgFe LDH reduced metal ion concentrations to levels below USEPA standards (<0.005 mg/L and 0.003 mg/L for Cd(II) and U(VI), respectively) for up to 4000 bed volumes, demonstrating its potential for wastewater treatment.

Enhancing interfacial Li+ transport and dielectric properties in poly(ethylene oxide)-based all-solid electrolytes via inactive g-C3N4 nanosheets filler incorporation

The advancement of all-solid-state Li metal batteries (ASSLMBs) faces a major challenge in the growth of lithium dendrites on the anode-electrolyte interface. In this study, we propose a dual-filler approach using poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) that combine Li1.4Al0.4Ti1.6(PO4)3 (LATP) ion-conductive particles with graphitic carbon nitride (g-C3N4) nanosheets. Analysis through second harmonic resonance enhanced electrostatic force microscopy and critical current density (CCD) tests reveal that the g-C3N4 additives form nano-capacitors at the SPE-lithium interface, effectively reducing sudden changes in current densities. The distribution of relaxation time constant (DRT) measurements confirms that the g-C3N4 filler suppresses uncontrolled Li dendrite growth, effectively mitigating battery aging caused by anode interfacial degradation. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis indicates that the nitrogen-containing organic groups in g-C3N4 are reduced to form a stable interfacial layer with lithium metal. As a result of these enhancements, the electrolyte demonstrates remarkable interfacial stability in Li/Li symmetrical cells at 0.65 mA/cm2 and delivers promising performance in assembled Li-LiFePO4 batteries, achieving a reversible capacity of 121.6 mAh/g at 1 C after 200 cycles. These findings highlight the potential of dual-filler PEO-based SPEs for promoting interfacial lithium-ion transport in all-solid-state Li metal batteries.

A novel molecularly imprinted electrochemical sensor based on graphitic carbon nitride nanosheets decorated bovine serum albumin@MnO2 nanocomposite for zearalenone detection

Zearalenone (ZEA), as a carcinogenic mycotoxin, is widely found in a wide variety of food products such as grains and its carcinogenicity, neurotoxicity, and estrogenic effects on humans were reported. In this report, a novel electrochemical sensor based on graphitic carbon nitride nanosheets decorated bovine serum albumin@MnO2 (g-C3N4NS/BSA@MnO2) nanocomposite and molecularly imprinted polymers (MIPs) was developed and applied to rice samples for ZEA determination. Firstly, the synthesis of bulk g-C3N4 by thermal poly-condensation method was completed. After the ultra-sonication treatment of bulk g-C3N4 providing graphitic carbon nitride nanosheets, the nanocomposite was successfully produced via electrostatic forces between g-C3N4NS and BSA@MnO2. Then, a novel MIP-based electrochemical electrode including g-C3N4NS/BSA@MnO2 was prepared in the presence of ZEA as target analyte and pyrrole (Py) monomer by cyclic voltammetry (CV). The formed electrochemical sensor exhibited a linearity of 1.0 – 10.0 ng L−1 with a detection limit (LOD) of 0.25 ng L−1. Furthermore, the high selectivity, reproducibility and stability of the prepared MIPebased electrochemical sensor exhibited that it could be used in real sample analysis such as rice.

Two-photon phototriggering of ROS storm in ruthenium(II) coordinated carbon nitride for robust cancer immunotherapy

The use of Ru(II) polypyridine complexes for photodynamic therapy is receiving much attention. Despite their promising properties, these compounds are associated with a poor excitation in the biological spectral window, a highly reduced or complete loss of the therapeutic effect under hypoxic conditions, and no immune response, limiting their application. To overcome all these limitations, herein, the coordination of Ru(II) polypyridine complexes to graphitic carbon nitride nanosheets for oxygen-self-sufficient two-photon photodynamic immunotherapy is presented. The conjugates were found with an exceptionally strong two-photon absorption and could self-sufficiently produce an ROS storm consisting of •O2-, •OH, and 1O2. Upon two-photon irradiation, the nanomaterial induced cell death in hypoxic monolayer cancer cells and multicellular tumor spheroids by a combination of apoptosis, paraptosis, ferroptosis, and immunogenic cell death. The nanomaterial was found with a strong tumor growth inhibition against the primary and secondary distant tumor in a melanoma-bearing mouse model through activation of the immune system.

Engineering the activity and stability of ZIF-8(Zn/Co)@g-C3N4 nanocomposites and their synergistic action in converting atmospheric CO2 into cyclic carbonates

The development of novel catalytic materials that integrate multifunctional sites has significant implications for expanding the utilization of CO2 resources. However, simultaneously achieving high activity and stability remains a formidable challenge. In this study, a series of ZIF-8(Zn/Co)@g-C3N4 nanocomposites were prepared by employing a thermo-physical compounding strategy that involved the combination of nitrogen-rich graphitic carbon nitride (g-C3N4) nanosheets with ZIF-8(ZnCo). The influences of different compositions of g-C3N4 and ZIF-8(Zn/Co) on the catalyst structure were systematically investigated. Subsequently, the catalytic activities of these nanocomposites towards the cycloaddition reaction between CO2 and epoxide were examined under different conditions. The presence of abundant Lewis base sites in g-C3N4 facilitates CO2 activation, while multiple Lewis acid sites in ZIF-8(Zn/Co) enable efficient epoxide activation. By working synergistically with a co-catalyst, tetrabutylammonium bromide (TBAB), CO2 and epoxides can be efficiently reacted to synthesize the corresponding cyclic carbonates under mild or even atmospheric pressure conditions. The catalytic reaction conditions were optimized, and both the catalyst's recycling performance and the scope of epoxides with various substituents were investigated. The integration of g-C3N4 and ZIF-8(Zn/Co) endows the catalytic material with exceptional structural stability and remarkable catalytic activity, thereby providing a new platform for highly efficient CO2 conversion.

A methodical optimization of melamine and ammonium sulphate ratio for the formation of graphitic carbon nitride nanosheets

A facile method for the preparation of graphitic carbon nitride nanosheets (GCN NS) was reported by adjusting the melamine and ammonium sulphate ratio via 1:1, 1:1.25, 1:1.5, and 1:2 respectively. The bulk sheet with an average thickness of 112 nm was obtained in the absence of ammonium sulphate. Meanwhile, the nanosheets with 34 nm thickness was formed with a higher concentration of ammonium sulphate. The gases like hydrogen, ammonia, ammonium bisulphate, sulfur oxide, etc were generated at high temperature (550 °C) accelerate the exfoliation rate and lead to the formation of nanosheets. A significant electronic and crystallographic changes was observed in UV and XRD analysis, while introducing a higher concentration of ammonium sulphate. The GCN NS obtained at a 1:2 ratio has a band gap energy value of 2.77 eV, which is a more suitable material for photo and electrocatalytic applications.

Electrochemical Quantification of Dopamine Sensing in Human Samples Using Bromine Doped Layered gC3N4 Nanosheets

The halogen, bromine (Br) doped layered graphitic carbon nitride (gCN) nanosheets are constructed for a novel electrochemical detection of dopamine (DA). The Br is successfully immobilized in the gCN host lattice, in which Br provides an N-vacancy for -C-N bonding to improve electron transfer and enhance its electrocatalytic properties. The prepared nanosheets are studied by various analytical analyses and the electrochemical behavior of the designed electrode is studied using cyclic voltammetry (CV). The Br-gCN decorated screen-printed carbon electrode (SPCE) has superior electrochemical activity and is stable during exposure to varied pH, however, exhibited better catalytic activity at pH 7. The Br-gCN/SPEC electrodes and their high electrocatalytic performance are used for the detection of dopamine with a lower limit of detection (LoD) of 5 nM concentration. The Br-gCN decorated electrodes exhibited satisfactory results for cyclic stability (up to 100th cycle), repeatability (up to 6 cycles), reproducibility of similarly constructed 6 electrodes, and their electrochemical performance. Furthermore, the fabricated sensor also exhibited a better recovery (>80%) for real-time urine sample analyses.

Reduced band gap in 2D-C3N4 nanosheets decorated with silver and gold adatoms

Abstract Two-dimensional materials have attracted significant attention due to their unique electronic properties. In this study, we investigate the effect of silver and gold adatoms on the band gap of graphitic carbon nitride (g-C3N4) nanosheets (2D-C3N4) using density functional theory. We examine several decorations with one-sided and two-sided combinations and find that the adsorption of gold and silver adatoms reduces the band gap of 2D-C3N4, which is consistent with experimental findings. Furthermore, we observe that all one-sided configurations are buckled. Our study provides insights into the electronic properties of 2D-C3N4 nanosheets and their potential applications in optoelectronics.

Heterojunctions Comprised of Graphitic Carbon Nitride Nanosheets and SnO2 Nanoparticles with Exposed {221} Crystal Facets for Photocatalytic Hydrogen Evolution

Heterojunctions Comprised of Graphitic Carbon Nitride Nanosheets and SnO₂ Nanoparticles with Exposed {221} Crystal Facets for Photocatalytic Hydrogen Evolution

Synergistic enhancement of photocatalytic hydrogen evolution by ultrathin oxygen-doped graphitic carbon nitride nanosheets loaded amorphous mesoporous nickel hydroxide

Graphitic carbon nitride (g-C3N4, CN) is widely utilized in the field of photocatalytic hydrogen production owing to its exceptional visible light absorption, addressing the challenge of energy scarcity. However, its development has been hindered by the issue of low charge separation efficiency. In this study, an ultrathin (∼1.65 nm) oxygen-doped graphitic carbon nitride nanosheets loaded amorphous mesoporous nickel hydroxide (a-Ni(OH)2/OCN) photocatalyst was developed through a straightforward calcination and stirring approach. Under visible light irradiation, a-Ni(OH)2/OCN exhibited a remarkably high photocatalytic hydrogen evolution rate of 4764.9 μmol·h−1 g−1, which is 4.7 times greater than that of the original CN. The synergistic effect between O-doping and heterojunction was proved by experimental data analysis combined with DFT calculations. Totally, the introduction of oxygen into CN led to a reduction in its band gap, while a-Ni(OH)2/OCN heterojunction achieved a broaden light absorption range and an effective charge separation due to a type-Ⅱ internal electric fields.

Asymmetric phthalocyanine-graphitic carbon nitride nanosheets conjugate on zinc oxide fibers for combined ultrasound and visible light driven degradation of Rhodamine 6G

This study reports on the fabrication of zinc-phthalocyanine (complex 3) linked to graphitic carbon nitride nanosheets and supported on zinc oxide fibers (to form 3-g-C3N4-ZnO fibers) as a potential catalyst for photo, sono and photosono-degradation of Rhodamine 6G. The catalysts were characterized using spectroscopic and microscopic techniques. The 3-g-C3N4-ZnO fibers showed higher degradation activity when compared to the individual components, with 96.7 % degradation efficiency achieved in the photosono process. The degradation followed pseudo first order kinetics. Singlet oxygen was the dominant reaction species in photo-catalytic process, while both singlet oxygen and hydroxide radicals were dominant species in the sono- and photosono-degradation processes. The obtained results suggest that the 3-g-C3N4-ZnO fibers are promising catalysts for degradation of organic pollutants.

An efficient catalytic reduction of nitroarenes over metal‐organic framework‐derived magnetic graphitic carbon nitride nanosheet

Metal–organic frameworks (MOFs) have emerged as highly viable and environmentally friendly alternatives to traditional catalysts within the catalytic family. This project delves into the investigation and subsequent reporting of the remarkable catalytic performance exhibited by magnetic Ox‐CN‐Cu‐MOF in the reduction of nitroarenes. The synthesis of magnetic Ox‐CN‐Cu‐MOF was achieved through a streamlined and intricate process, with its structure meticulously identified via various analytical methods including high‐resolution transmision electron microscopy (HRTEM), X‐ray diffraction (XRD), scanning electron microscopy/energy dispersive X‐ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), vibrating‐sample magnetometry (VSM) and thermogravimetric (TG) analysis. Of particular significance, the loading of copper (Cu) and its potential leaching were effectively detected through inductively coupled plasma optical emission spectroscopy (ICP‐OES) analysis. The catalytic efficacy of magnetic Ox‐CN‐Cu‐MOF was evaluated during the conversion of nitro compounds o related‐amines utilizing NaBH4 as the reductant. Remarkably, the unique structure and Lewis acidic properties of copper in the metal nodes contributed to the exceptional catalytic behavior exhibited by the magnetic Ox‐CN‐Cu‐MOF catalyst, surpassing that of previously reported catalysts. Furthermore, magnetic Ox‐CN‐Cu‐MOF demonstrated exceptional recyclability, as validated through repetitive continuous usage.

Fe-doped two-dimensional graphite carbon nitride: An effective nanozymetic catalyst for electrochemical detection of cell-released H2O2

In this work, a simple one-step pyrolysis process was designed to synthesize Fe-doped graphite carbon nitride (Fe–C3N4) nanosheets with FeCl3 as Fe source. The resulted samples were characterized by various characterization techniques, and the results showed that Fe species might form Fe–N bonds with N atoms of C3N4, which was similar to the iron (II) porphyrin active center of horseradish peroxidase. Then Fe–C3N4 nanosheet was further mixed with carbon nanotube (CNT) to obtain Fe–C3N4@CNT nanocomposite, which was further modified on the self-made flexible printed electrode (PE) to construct the flexible working electrode. Fe–C3N4 nanosheets show good catalytic activity for H2O2 and the introduction of CNT can effectively improve the electron transfer efficiency at the modified electrode interface. By combining with wireless portable electrochemical workstation, the sensor shows a wider detection range (10.0 μmol L−1–20.0 mmol L−1) and a lower limit of detection (0.38 μmol L−1, S/N = 3) for the H2O2 analysis. Furthermore, the sensor can be applied to the real time and in-situ analysis of H2O2 secreted from live cells. In word, this self-supported sensing electrode shows great potential applications in monitoring the pathological and physiological dynamics of cancer cells.

Graphitic Carbon Nitride Nanosheets Decorated with Zinc-Cadmium Sulfide for Type-II Heterojunctions for Photocatalytic Hydrogen Production.

In this study, we fabricated graphitic carbon nitride (g-C3N4) nanosheets with embedded ZnCdS nanoparticles to form a type II heterojunction using a facile synthesis approach, and we used them for photocatalytic H2 production. The morphologies, chemical structure, and optical properties of the obtained g-C3N4-ZnCdS samples were characterized by a battery of techniques, such as TEM, XRD, XPS, and UV-Vis DRS. The as-synthesized g-C3N4-ZnCdS photocatalyst exhibited the highest hydrogen production rate of 108.9 μmol·g-1·h-1 compared to the individual components (g-C3N4: 13.5 μmol·g-1·h-1, ZnCdS: 45.3 μmol·g-1·h-1). The improvement of its photocatalytic activity can mainly be attributed to the heterojunction formation and resulting synergistic effect, which provided more channels for charge carrier migration and reduced the recombination of photogenerated electrons and holes. Meanwhile, the g-C3N4-ZnCdS heterojunction catalyst also showed a higher stability over a number of repeated cycles. Our work provides insight into using g-C3N4 and metal sulfide in combination so as to develop low-cost, efficient, visible-light-active hydrogen production photocatalysts.

Programming DNA walker and DNA tetrahedral nanostructures mediated CRISPR/Cas12a electrochemiluminescence biosystem and its biosensing application

A CRISPR/Cas12a electrochemiluminescence (ECL) biosensor based on the multiple sites DNA walker with controlled swing arm position, integrating Tribulus terrestris-like AuCu nanoterrestris (AuCu NTs) and DNA tetrahedral nanostructures (DTNs) is constructed for ultrasensitive detection of miRNA-21. The AuCu NTs was served as a co-reaction accelerant to promote the reduction of S2O82- at the cathode, which can be rapidly converted with S2O83•- and significantly enhance the ECL signal from graphitic carbon nitride nanosheets. Meanwhile, by virtue of the excellent stability of DNA tetrahedral nanostructure, the binding efficiency between single strand DNA and luminescent materials was improved. Afterward, DNA walker signal amplifier converted and amplified the target miRNA-21 into transitional DNA under the activity of Nt.BsmAI nicking endonuclease, thereby activating trans-cleavage ability of CRISPR/Cas12a and achieving the efficient annihilation of ECL signals was employed. As a proof of concept, the as-constructed biosensor demonstrated well specificity and sensitivity towards miRNA-21 with the range of 1.0 fM to 10 nM and the detection limit was 0.339 fM (S/N = 3). Therefore, the proposed strategy expanded the scope of application of CRISPR/Cas12a and demonstrated potential of diagnostic analysis.

Improving the charge kinetics through in-situ growth of NiSe nanoparticles on g-C3N4 nanosheets for efficient hybrid supercapacitors

Nickel selenide (NiSe) has been a promising positive electrode for hybrid supercapacitors due to its multiple oxidation states, tunability, and high specific capacity. However, sluggish ion transfers and particle agglomeration hamper its electrochemical performance. In the present study, we have grown NiSe nanoparticles on two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanosheets to realize three-dimensional (3D) architecture. The 2D support, high nitrogen content, and features of g-C3N4 enhanced the specific capacity of the NiSe/g-C3N4 nanocomposite material. The resulting nanocomposite shows a specific capacity of 320 mA h g−1 at a current density of 1 A g−1, which is considerably higher than pristine NiSe. Later, the hybrid supercapacitor (HSC) device was fabricated using NiSe/g-C3N4 composite as positive and activated carbon (AC) as negative electrodes. The cell delivered an energy density of 52.5 Wh kg−1 at a power density of 1488 W kg−1 with excellent cyclic stability of 84.9% over 8000 cycles. The electrochemical performance enhancement corresponds to a 3D structure, high electrochemical active sites, and improved charge transportation at the electrode/electrolyte interface. Thus, the present work offers an easy approach and architectural design for high-performance HSC.

Green reduction and uniform assembly of silver nanoparticles on polydopamine functionalized sulfur-doped graphitic carbon nitride nanosheets for highly sensitive H2O2 detection via nonenzymatic approach

In this study, we demonstrate a new strategy to fabricate an enzyme-free hydrogen peroxide (H2O2) sensor electrode based on silver nanoparticles (AgNPs) decorated polydopamine/sulfur-doped graphitic carbon nanocomposite (denoted as AgNPs@PDA/S-g-C3N4). The S-g-C3N4 nanosheets are derived from the pyrolysis of trithiocyanouric acid, followed by thermal exfoliation. A mussel-inspired PDA nanolayer enhances the solubility and high dispersion of S-g-C3N4 nanosheets and AgNPs in aqueous phase synthesis. The amine and catecholic functional groups of PDA are the major nucleation sites for Ag+ ions adsorption and ascorbic acid was further used as a green reducing agent for the growth of AgNPs. PDA adhesion layer can effectively connect the AgNPs and S-g-C3N4 nanosheets via electrostatic interaction to increase the stability and biocompatibility of the ternary composite structure. Various spectroscopy and microscopy techniques confirmed the formation of AgNPs@PDA/S-g-C3N4 nanocomposite. Our AgNPs@PDA/S-g-C3N4 nanocomposite fabricated disposable sensor exhibited outstanding sensing ability to H2O2 reduction at −0.65 V (vs. Ag/AgCl), which is confirmed through an amperometric detection method. The sensor exhibits rapid response (2 s) to H2O2 sensing with high sensitivity (1020 μA mM−1 cm−2), wide detection range (0.002–23 mM) and low limit of detection of 0.086 μM. The practicality of the H2O2 sensor was evaluated with commercial milk and mouthwash samples, which retained satisfactory recoveries. Thus, our results indicate that the PDA functionalization not only enhances the S-g-C3N4 solubility but also increases the interfacial charge transport in AgNPs@PDA/S-g-C3N4 nanocomposite material which develops a potential sensing method for nonenzymatic H2O2 sensor. Due to the effective surface modification strategies, such as PDA nanocoating and AgNPs deposition, the exfoliated S-g-C3N4 nanosheets gained excellent electrochemical properties, facilitating potential candidates in electrochemical applications.