Graphitic Nanosheets Research Articles

DNAzyme-Mediated Biodeposition Coupling Adjustable Cascade Electric Fields for Photoelectrochemical Telomerase Activity Monitoring.

Telomerase, as a specialized reverse transcriptase, plays a vital role in early cancer diagnostics and prognosis; thus, developing efficient sensing technologies is of vital importance. Herein, an innovative "signal-on-off" photoelectrochemical (PEC) sensing platform was developed for ultrasensitive evaluation of telomerase activity based on an electron-transfer tunneling distance regulation strategy and DNAzyme-triggerable biocatalytic precipitation. Concretely, cascade internal electric fields between CuInS2 quantum dots (QDs), graphitic carbon nitride nanosheets (g-C3N4 NSs), and TiO2 nanorod arrays (NRAs) were developed to realize cascade electron extraction and hole transfer. Enabled by such a design, an effective "signal-on" state to gain a progressively enhanced PEC output was designed by suppressing the photogenerated electron-hole pair recombination. With the introduction of hairpin probe H2 and the subsequent extension of the primer sequence driven by the target telomerase, the CuInS2 QDs labeled with hairpin probe H1 were programmatically unfolded, resulting in CuInS2 QDs' close proximity to the working electrode away from the cascade interface, accompanied by the formation of G-quadruplex/hemin complexes. The gradual undermining of tunneling distance and implantation of DNAzyme-initiating biocatalytic precipitation tremendously induced the sluggish migration kinetics of the photoinduced charge, accompanied by the photocurrent intensity decrement, leading to the "signal-off" state. Under optimized conditions, the as-prepared PEC biosensor realizes ultrasensitive detection of telomerase activity from 10 to 105 cell·mL-1 with a detection limitation of 3 cells·mL-1. As a proof of concept, this well-designed method provides new insights into signal amplification for telomerase activity evaluation and also presents promising potential for further development in drug screening, healthcare diagnostics, and biological assays.

Graphitic carbon nitride nanosheets mitigate cadmium toxicity in Glycine max L. by promoting cadmium retention in root and improving photosynthetic performance

Cadmium (Cd) pollution poses a serious threat to plant growth and yield. Nanomaterials have shown great application potential for alleviation of Cd toxicity to plants. In this study, we applied graphitic carbon nitride nanosheets (g-C3N4 NSs) for alleviation of Cd-toxicity to soybean (Glycine max L.). The g-C3N4 NSs supplementation significantly improved plant growth and reduced oxidative damage in the Cd-toxicated soybean seedlings through hydroponic culture. Particularly, the g-C3N4 NSs dynamically regulated the root cell wall (RCW) components by increasing pectin content and modifying its demethylation via enhancing pectin methylesterase (PME) activity, therefore greatly enhanced stronger RCW-Cd retention (up to 82.8%) and reduced Cd migration to the shoot. Additionally, the g-C3N4 NSs reversed the Cd-induced chlorosis, increased photosynthetic efficiency because of enhancement in Fv/Fm ration, Y(II) and sugars content. These results provide new insights into the alleviation of Cd toxicity to plants by g-C3N4 NSs, and shed light on the application of low-cost and environmental-friendly carbon-based NMs for alleviating heavy metal toxicity to plants.

Fabrication of LaFeO3-nitrogen deficient g-C3N4 composite for enhanced the photocatalytic degradation of RhB under sunlight irradiation

LaFeO3-nitrogen deficient g-C3N4 (LaFeO3-g-C3N4-H) heterostructure has been fabricated obtaining thermal polymerization of acetic acid-treated melamine followed by incorporation of perovskite-type LaFeO3 onto the graphitic carbon nitride nanosheets (g-C3N4) using La(NO3)3·6H2O and Fe(NO3)3·9H2O as precursors. The as-synthesized nanocomposite was investigated using Fourier Transform Infrared Spectroscopy (FT-IR), powder X-ray diffraction (XRD), UV–Vis Diffuse Reflection Spectroscopy (UV–Vis DRS), Scanning Electron microscope (SEM), and Transmission Electron microscope (TEM). The findings of the characterization study revealed the successful incorporation of LaFeO3 on g-C3N4-H nanosheets. The band gap energy of LaFeO3-g-C3N4-H heterojunctions was found to be active in the visible light region. The LaFeO3-g-C3N4-H ability to degrade Rhodamine B (RhB) dye in an aqueous solution was investigated under sunlight illumination. The results of photocatalytic degradation activity showed that LaFeO3-g-C3N4-H photocatalyst haspresented the highest photocatalytic efficiency of 99.5% after 60 min under sunlight irradiation. The remarkable photocatalytic activity can be attributed to the defect structure of g-C3N4 and the construction of heterojunction. In addition, LaFeO3-g-C3N4-H showed promise recyclability after 5 cycles with slight activity reduction.

Synthesis and characterization of enhanced visible light-driven C-doped ZnO-2D GO/g-C3N4 heterojunction photocatalyst

Well-designed 2D graphene oxide-modified polymeric graphitic carbon nitride composite nanosheets (GO/g-C3N4) as desirable sensitizers and catalytic substrates for optimising the visible light-driven photocatalytic performance of ZnO-based photocatalysts have been investigated. Herein, 2D GO/g-C3N4 composite nanosheets are first developed by ultrasonic and hydrothermal methods, and then coupled with ZnO nanoparticles to prepare a series of ternary GO/g-C3N4-ZnO heterojunction composites with vary GO loading concentrations. Characterization of the photocatalysts was carried out by SEM, TEM, XPS, XRD, DRS, photoluminescence (PL) spectroscopy; evaluation of the visible light photocatalytic activity was performed by degrading an aqueous methylene blue (MB) solution. XPS studies showed that the formation of a ZnC bond in 15 % GO/g-C3N4-ZnO is due to the replacement of oxygen by carbon, indicating the construction of a hybrid heterojunction composed of C-doped ZnO and visible light sensitive GO/g-C3N4 composite nanosheets. The photodegradation performance of 15 % GO/g-C3N4-ZnO is 5.3, 2.9, and 2.2 times higher than that of pure ZnO, g-C3N4, and g-C3N4-ZnO, respectively. Due to the increase of GO loading in GO/g-C3N4 composite nanosheets, some characteristics of efficient visible light photocatalysis, such as a wider light absorption range, fluorescence quenching in the PL spectrum, excellent optical response in photocurrent measurement, and good stability，were confirmed and can be attributed to the electronic interaction between heterostructures and the effective transfer of photogenerated electrons in these ternary nanocomposites. This work may provide a new promising pathway for the construction of easily prepared 2D GO/g-C3N4 hybrid-modified nanocomposites, which is a hopeful material for wastewater control.

Nitrogen vacancies-engineered graphitic carbon nitride nanosheets for boosting photocatalytic H2 production

Defect engineering can be considered a powerful strategy for enhancing photocatalytic performance. Here, we successfully synthesized tri-coordinated nitrogen vacancies-modified graphitic carbon nitride (Nv-GCN) by employing a simple sintering process. The optimized Nv-GCN shows boosted photocatalytic H2 production (5.45 mmol g−1 h−1) in comparison with that of the pristine GCN (0.69 mmol g−1 h−1) under visible light irradiation. It is found that the nitrogen vacancies provide more active sites in photocatalytic reactions. Meanwhile, the electronic structure of Nv-GCN can be modulated by nitrogen vacancies, and defect levels are formed in the intrinsic bandgap. The introduced nitrogen vacancies not only broaden the range of visible-light absorption and narrow the band gap of GCN but also accelerate the separation and transfer of the photogenerated charges. This study provides an effective route for designing high-performance photocatalysts for highly efficient conversion of solar energy.

Pt-Ni contact engineering in carbon nitride based photocatalysts for hydrogen production

The effect of a binary PtNi co-catalyst supported on graphitic carbon nitride nanosheets is studied in the photo-production of hydrogen from methanol:water mixtures. The physicochemical analysis provides evidence that the carbon nitride support allows the formation of highly dispersed PtNi nanoparticles with an average composition of Pt 85 % Ni 15 %. The binary system outperforms the monometallic Pt and Ni counterparts and renders an extraordinary quantum efficiency of 8.8 % for hydrogen photo-production. The formation of a PtNi alloy, with a Pt-enriched surface and electronic properties influenced by the heterometallic contact, provides high and stable activity, mostly as a consequence of the effects that the co-catalyst exerts on the charge carrier handling capability of the solid.

High-performance robust graphitic carbon nitride nanosheets embedded membranes for desalination through direct contact membrane distillation

Two-dimensional (2D) graphitic carbon nitride (g-C3N4)-based membranes have recently received widespread attention due to their fantastic separation performance. In the present investigation, for the first time, we assessed the desalination performance of membranes incorporated with g-C3N4 nanosheets through the membrane distillation (MD) process. For this purpose, different concentrations (0–0.06 wt.%) of synthesized nanosheets were embedded within the hydrophobic PVDF matrix by simple phase inversion method. Upon loading 0.03 wt.% g-C3N4, the water contact angle and LEP augmented from 80.5° and 6 bar for the pure PVDF membrane to 95.2° and 8 bar, respectively. Adding the g-C3N4 nanosheets also improved both the tensile strength and the elongation at break by 21.32% and 36.46% than the pristine membrane, respectively. The mixed matrix membranes favorably improved MD performance; so that, 0.03 wt.% g-C3N4 embedded membrane exhibited a flux of 27.63 kg/m2h with an enhancement of 70% relative to its pure counterpart. Continuous testing for up to 24 h filtration of a 3.5 wt.% NaCl solution still showed a stable flux and almost complete salt rejection for the mentioned mixed matrix membrane. The anti-fouling properties of the membranes were also improved by incorporation of the g-C3N4 nanosheets. The 0.03 wt.% gCN embedded membrane recovered about 90% of the original permeation flux after 20 h desalination operations using real seawater as a feed solution. This work holds promise for developing next-generation MD membranes with superior desalination performance in terms of water vapor permeability and salt rejection.

Porous cyclopentadiene unit-incorporated graphitic carbon nitride nanosheets for efficient photocatalytic oxidation of recalcitrant organic micropollutants in wastewater

For the purpose of searching for efficient photocatalysts to deal with recalcitrant organic micropollutants in wastewater, here an in-situ supramolecule self-assembly-thermal polymerization strategy is developed to prepare a series of porous cyclopentadiene (CPD) unit-incorporated g-C3N4 ultrathin nanosheets (CCPD-g-C3N4). The CCPD-g-C3N4 demonstrate CPD unit doping level-dependent and remarkably enhanced visible-light photocatalytic oxidation efficiency towards two organic micropollutants, acetaminophen and methylparaben, in which the optimized CCPD-g-C3N4-2 shows 6.1 and 3.5 times higher acetaminophen and methylparaben degradation rate than bulk g-C3N4; moreover, CCPD-g-C3N4-2 is still robust and efficient in the treatment of five mixed organic micropollutants in pharmaceutical wastewater, and the satisfactory micropollutant removal efficiency is obtained in a wide pH window and the presence of high concentrations of inorganic anions and cations as well as dissolved organic matters. Theoretical calculation combined with experimental test reveal that CCPD-g-C3N4 can significantly reduce ecological risk of the target pollutant after the photocatalytic degradation reaction. Such enhanced photocatalytic oxidation efficiency is dominated by the accelerated charge carrier separation dynamics and extended visible-light response region due to the incorporation of CPD units, which finally lead to the generation of abundant reactive oxygen species to degrade and mineralize target micropollutants efficiently.

Fabrication of N-doped graphitic carbon nanosheets via reaction between CaC2 and g-C3N4 as promising Li-ions battery anode

Nitrogen-doped carbon materials have attracted much attention for energy storage. Herein, we synthesize nitrogen-doped graphitic carbon nanosheets (NGCN) via a simple reaction between g-C3N4 and CaC2. The NGCN product integrates various features including high nitrogen content (3.98 at.%), large surface area (72.96 m2 g−1) and high graphitization degree (interplanar spacing, 0.335 nm). When served as anode material in Li-ions batteries, the NGCN exhibits a quite encouraging reversible capacity of 475 mAh g−1 at a current density of 500 mA g−1, with a capacity retention of 98.5 % after 1000 cycles. It also has an acceptable rate capability (238 mAh g−1 at 5000 mA g−1). This work promises an efficient route to convert sustainable carbon sources into nitrogen-doped graphitic carbon nanosheets with excellent electrochemical performances for energy storage.

Exploiting Iodine Redox Chemistry for Achieving High‐Capacity and Durable PEO‐Based All‐Solid‐State LiFePO4/Li Batteries

AbstractPoly (ethylene oxide) (PEO)‐based electrolytes are extensively applied to LiFePO4/Li solid‐state batteries on account of their high safety and good flexibility. Nevertheless, the unsatisfactory energy density and inferior lifespan of the batteries still inhibit their large‐scale applications. Herein, graphitic carbon nitride nanosheets (GCN)‐assisted‐alkali metal iodides are proposed as multifunctional fillers for PEO‐based electrolytes. GCN is introduced to fix the location of iodine species through adsorption to reduce iodine migration and promote the kinetics of iodine redox reactions. Besides reducing the PEO crystallinity and elevating the ionic conductivity of electrolyte, the incorporation of GCN‐assisted‐alkali metal iodides facilitates lithium migration, constructs a stable interphase on the Li anode, and enables uniform deposition of lithium. Of particular note, extra capacity is provided through iodine redox reactions. The all‐solid‐state LiFePO4/Li battery using GCN‐LiI modified PEO electrolyte (GCN‐LiI‐PEO) delivers a high discharge capacity of 228.4 mAh g−1 at 0.1 C. Superior rate capability with 99.2 mAh g−1 at 10 C and high‐capacity retention of 87.3% after 900 cycles at 0.5 C are also achieved. Moreover, the LiFePO4/Li batteries using GCN‐assisted‐KI or NaI also achieve high capacity and prolonged cycle life. This work opens a promising avenue for pursuing high‐energy density solid‐state batteries.

Synthesis and characterization of nitrogen and phosphorus co-doped TiO2 nanoparticle anchored graphitic carbon nitride nanosheets: Photocatalytic application on dye removal

In this study, nitrogen and phosphorus co-doped titanium dioxide (NP-TiO2) nanoparticles are anchored onto graphitic carbon nitride nanosheets (GCN) by the simple sonochemical method. The synthesized NP-TiO2/GCN nanocomposites are characterized by UV–Visible absorbance spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, Photoluminescence spectroscopy, Scanning electron microscopy and Transmission electron microscopy. We find that the co-doping of nitrogen and phosphor to TiO2 nanoparticles of size (10–25) nm as well as simultaneous anchoring onto GCN nanosheets. The optimised 2.5 wt% GCN in NP-TiO2/GCN showed complete degradation of MB dye and MO dye at 105 min and 60 min respectively. The photocatalytic degradation performance is 5 times superior to that of individual NP-TiO2 and GCN under visible light. The degradation rate constants of NP-TiO2/GCN is found to be 0.01491 min−1 for MB dye and 0.02153 min−1 for MO dye. The improved photocatalytic performance of NP-TiO2/GCN nanocomposite is due to the synergistic effects of both NP-TiO2 and GCN, which decrease the bandgap as well as charge recombination.

Ultrasound-Augmented Multienzyme-like Nanozyme Hydrogel Spray for Promoting Diabetic Wound Healing.

Treatment of diabetic foot ulcers (DFU) needs to reduce inflammation, relieve hypoxia, lower blood glucose, promote angiogenesis, and eliminate pathogenic bacteria, but the therapeutic efficacy is greatly limited by the diversity and synergy of drug functions as well as the DFU microenvironment itself. Herein, an ultrasound-augmented multienzyme-like nanozyme hydrogel spray was developed using hyaluronic acid encapsulated l-arginine and ultrasmall gold nanoparticles and Cu1.6O nanoparticles coloaded phosphorus doped graphitic carbon nitride nanosheets (ACPCAH). This nanozyme hydrogel spray possesses five types of enzyme-like activities, including superoxide dismutase (SOD)-, catalase (CAT)-, glucose oxidase (GOx)-, peroxidase (POD)-, and nitric oxide synthase (NOS)-like activities. The kinetics and reaction mechanism of the sonodynamic/sonothermal synergistic enhancement of the SOD-CAT-GOx-POD/NOS cascade reaction of ACPCAH are fully investigated. Both in vitro and in vivo tests demonstrate that this nanozyme hydrogel spray can be activated by the DFU microenvironment to reduce inflammation, relieve hypoxia, lower blood glucose, promote angiogenesis, and eliminate pathogenic bacteria, thus accelerating diabetic wound healing effectively. This study highlights a competitive approach based on multienzyme-like nanozymes for the development of all-in-one DFU therapies.

The different impacts of g‐C3N4 nanosheets on PVDF and PSF ultrafiltration membranes for Remazol black 5 dye rejection

AbstractMembranes combined with nanoparticles are an excellent combination capable of successfully removing various contaminants, such as dyes from wastewater while using very little energy and decreasing pollution. The present study reports an efficient approach for Remazol Black 5 (RB5) dye removal using composite graphitic carbon nitride nanosheets (g‐C3N4), polysulfone (PSF), and polyvinylidene fluoride (PVDF) membranes. The membranes were prepared using the phase inversion method, with varying quantities of g‐C3N4 nanosheets ranging from 0.1%, 0.2% to 0.3%. The prepared g‐C3N4 nanosheets were characterized by FTIR, SEM analyses, and zeta potential measurements. FTIR and SEM studies, contact angle, water permeability, COD, and dye rejection measurements were used to characterize the g‐C3N4 nanosheets embedded in PSF and PVDF membranes. After the addition of 0.3 wt% g‐C3N4, the water flux of the 0.3 wt% g‐C3N4 embedded PSF membrane was the highest, whereas the water flux of the 0.3 wt% g‐C3N4 embedded PVDF membrane was the lowest. The ultrafiltration (UF) membrane's performance with g‐C3N4 embedded showed an RB5 rejection rate of more than 80% and a COD removal efficiency of more than 45%. The results of the experimental filtration showed that RB5 rejection reached maximum values of 91.3% for 0.1 wt% g‐C3N4/PSF, and 85.6% for 0.3 wt% g‐C3N4/PVDF.

Rod-like graphitic carbon nitride nanosheets with copper ions for effective DNA cleavage and anticancer studies

Graphitic Carbon Nitride (g-CN) nanomaterials are emerging effective biomaterials and play a vital role in the biodiversity research area due to their biocompatibility, and less toxic nature. The nanosized g-CN rod-like nanosheets were synthesized and characterized with XRD, FTIR, UV–Vis and Fluorescence spectroscopy, FESEM, EDAX and HRTEM analysis. The g-CN appears almost immediately. DNA cleavage and anticancer activity investigations were conducted using Cu2+ ions. The size and Lewis acidic and Lewis basic functions of Cu2+/g-CN played a vital role in effective DNA cleavage and anticancer activity were demonstrated. The g-CN, Cu2+ ions, Cu2+/g-CN nanostructure and its various concentrations at different times were studied for the DNA cleavage and anticancer activity. The DNA interaction with Cu2+ ions/g-CN rod-like nanosheets was also established with UV–Vis and Fluorescence analysis. The Cu2+/g-CN nanostructure showed highly efficient activity than the other concentrations and controls were used in this study. The specificity and effectiveness of the present DNA slicing agent and anticancer nano-drug carrier system may value the investigation of cancer pharmaceutics.

Enzymatic reaction modulated DNA assembly on graphitic carbon nitride nanosheets for sensitive fluorescence detection of acetylcholinesterase activity and inhibition.

A novel fluorescent strategy has been developed by using anenzymatic reaction modulated DNA assembly on graphitic carbon nitride nanosheets (CNNS) for the detection of acetylcholinesterase (AChE) activity and its inhibitors. Thetwo-dimensional and ultrathin-layer CNNS-material was successfully synthesized through a chemical oxidation and ultrasound exfoliation method. Because of its excellent adsorption selectivity to ssDNA over dsDNA and superior quenching ability toward the fluorophore labels, CNNS were employed to construct a sensitive fluorescence sensing platform for the detection of AChE activity and inhibition. The detection was based on enzymatic reaction modulated DNA assembly on CNNS, which involved the specific AChE-catalyzed reaction-mediated DNA/Hg2+ conformational change and subsequent signal transduction and amplification via hybridization chain reaction (HCR). Under the excitation at 485 nm, the fluorescence signal from 500 to 650 nm (λmax = 518 nm) of the developed sensing system was gradually increased with increasing concentration of AChE. The quantitative determinationrange of AChE is from 0.02 to 1 mU/mL and the detection limit was 0.006 mU/mL. The developed strategy was successfully applied to the assay of AChE in human serum samples, and can also be used to effectively screen AChE inhibitors, showing great promise providinga robust and effective platform for AChE-related diagnosis, drug screening, and therapy.

Rational design of dysprosium oxide nanochains decorated on graphitic carbon nitride nanosheet for the electrochemical sensing of riboflavin in food samples

Rational design of dysprosium oxide nanochains decorated on graphitic carbon nitride nanosheet for the electrochemical sensing of riboflavin in food samples

High-performance asymmetric supercapacitors utilizing manganese oxide nanoparticles grafted graphitic carbon nitride nanosheets as the cathode and hypercross-linked polymer derived activated carbon as the anode

Herein, we demonstrated the inexpensive construction of a high-performance asymmetric supercapacitor (ASC) that was combined with manganese oxide nanoparticles grafted graphitic carbon nitride nanosheets (Mn3O4@GCN-NS) as the cathode and nitrogen doped hypercross-linked polymer derived activated carbon (NHCP-AC) as the anode with 6.0 M aqueous KOH electrolyte. In the beginning, Mn3O4@GCN-NS was successfully prepared via a single-step pyrolysis assisted method and the NHCP-AC was synthesized via Friedel-Crafts reaction. The as-synthesized nanocomposites exhibited higher specific capacitance of 436.2 at 0.5 A g−1 in three-electrode cell configuration. Furthermore, the ASC device was fabricated by integrating Mn3O4@GCN-NS with NHCP-AC, which demonstrated considerable energy density of 22.2 Wh/kg at 400 W/kg power density together with remarkable cyclability (93.5 % capacitive retention even after 5000 cycles of charge and discharge). The light emitting diode (5 mm dia.) was powered for about 15 min using two ASC devices coupled in series, demonstrating the effectiveness of its power source. Thus, the results demonstrated that the ASC devices have enormous potential for investigating cutting-edge applications in the field of advanced energy storage.

Mechanism insight into enhanced photocatalytic hydrogen production by nitrogen vacancy-induced creating built-in electric field in porous graphitic carbon nitride nanosheets

An appealing and efficient route to modify the catalytic behavior of g-C3N4 (gCN) is to control textures and defects at the molecular scale, which is beneficial to enhancing its built-in electric field (BIEF) and accelerating the photogenerated charge carrier separation. Herein, we deliberately design a precursors-reforming strategy for enhancing the BIEF of gCN porous microstructures through constructing N vacancies to accelerate charge separation. The N vacancies can not only enhance the BIEF, thus accelerating photocharge delocalization, but also promote reaction kinetics. Also, the porous structures offer a large number of active sites to expedite the reaction and shorten the migration distance of photogenerated carriers to the surface. As anticipated, the modified gCN exhibits a much higher photocatalytic performance, around 7.1 times that of the bulk gCN. This work will provide a fascinating method to combine textures and electronic structure regulation for gCN-based photocatalysts.

Slow Cooling and Transfer Dynamics of Hot Excitons in CsPbBr3 Perovskite Quantum Dots/g-CN Nanosheet Heterostructures: Implications for Optoelectronic Applications

Slow cooling and long-lived hot carrier (HC) population plays a crucial role in crossing the Shockley–Queisser limit and achieving high-efficiency perovskite photovoltaic devices up to 66%. Herein, we investigated the slow cooling of HCs via charge transfer in in-situ synthesized CsPbBr3 perovskite quantum dots-decorated graphitic carbon nitride nanosheet (CsPbBr3 PQDs/g-CN NS) heterostructures using ultrafast transient absorption (UTA) spectroscopy. Halide perovskites showed excitation energy-dependent HC cooling. We examined the HC dynamics at two different excitation energies with varying excitation pump fluences. UTA revealed significantly higher slow cooling and slow bleach recovery in CsPbBr3 PQDs/g-CN NSs (i.e., 632 fs and 845 ps) compared to pure CsPbBr3 PQDs (i.e., 512 fs and 371 ps) at an excitation energy of 3.54 eV and a fluence of 250 μW, suggesting that HCs transfer through the heterostructure interface. The observed slow cooling can be explained by the stronger interaction between the organic polymeric frameworks of g-CN NSs and CsPbBr3 PQDs, which passivates the trap states of CsPbBr3 PQDs and offers slow electron–hole recombination by slowing down the Auger recombination or the hot-phonon bottleneck effect. Additionally, density functional theory (DFT) calculations were carried out to shed light on band alignment at the interface to reveal the mechanism of efficient charge transfer in CsPbBr3 PQDs/g-CN NSs and validate the experimental findings. The insight of this study is quite beneficial for designing modified perovskite nanostructures for realization in perovskite solar cells in the near future.

Dimensionality effects of g-C3N4 from wettability to solar light assisted self-cleaning and electrocatalytic oxygen evolution reaction

Unique interfacial properties of 2D materials make them more functional than their bulk counterparts in a catalytic application. In the present study, bulk and 2D graphitic carbon nitride nanosheet (bulk g-C3N4 and 2D-g-C3N4 NS) coated cotton fabrics and nickel foam electrode interfaces have been applied for solar light-driven self-cleaning of methyl orange (MO) dye and electrocatalytic oxygen evolution reaction (OER), respectively. Compared to bulk, 2D-g-C3N4 coated interfaces show higher surface roughness (1.094 > 0.803) and enhanced hydrophilicity (θ ∼ 32° < 62° for cotton fabric and θ ∼ 25° < 54° for Ni foam substrate) due to oxygen defect induction as confirmed from morphological (HR-TEM and AFM) and interfacial (XPS) characterizations. The self-remediation efficiencies for blank and bulk/2D-g-C3N4 coated cotton fabrics are estimated through colorimetric absorbance and average intensity changes. The self-cleaning efficiency for 2D-g-C3N4 NS coated cotton fabric is 87%, whereas the blank and bulk-coated fabric show 31% and 52% efficiency. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis determines the reaction intermediates for MO cleaning. 2D-g-C3N4 shows lower overpotential (108 mV) and onset potential (1.30 V) vs. RHE for 10 mA cm−2 OER current density in 0.1 M KOH. Also, the decreased charge transfer resistance (RCT = 12 Ω) and lower Tafel's slope (24 mV dec−1) of 2D-g-C3N4 make it the most efficient OER catalyst over bulk-g-C3N4 and state-of-the-art material RuO2. The pseudocapacitance behavior of OER governs the kinetics of electrode-electrolyte interaction through the electrical double layer (EDL) mechanism. The 2D electrocatalyst demonstrates long-term stability (retention ∼94%) and efficacy compared to commercial electrocatalysts.