Graphitic Carbon Nitride Oxide Research Articles

Investigation on two-dimensional molybdenum oxide-graphitic carbon nitride (MoO3-g-C3N4) heterostructures based hybrid electrodes for the fabrication of high energy density solid state supercapacitors

BackgroundThe fabrication of high-performance supercapacitor electrodes has been extensively investigated for future high power storage applications. Molybdenum trioxide (MoO3) was synthesized and the graphitic carbon nitride have been introduced with the MoO3 to enhance the electrochemical performance by synergistic effect. MethodsMoO3-gC3N4 Nanocomposite (NC) was synthesized by thermal treatment followed by sonication process and can be utilized as active material for the preparation of supercapacitor electrode. The solid-state hybrid supercapacitor device (SHSC) is fabricated with MoO3-gC3N4 NC as cathode, activated carbon as anode, and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) ionic liquid as an ionogel electrolyte to perform the electrochemical studies. Significant findingsCyclic voltammetry (CV) revealed that the synthesized composite delivers higher specific capacity of 520. 97 C/g at 10 mV/s. The electrochemical impedance spectroscopy (EIS) of MoO3-g-C3N4 NC reveals lower solution (Rs) and charge transfer resistance (Rct) of 0.05 and 3.14 Ω respectively. The fabricated MoO3-g-C3N4//AC SHSC delivers high energy density of 59.75 Wh/kg and a high-power density of 1125 W/kg. Furthermore, the SHSC exhibits superior cyclic stability of 86.1% even after 6000 consecutive charge-discharge cycles.

Pulsed laser-assisted synthesis of nano nickel(ii) oxide-anchored graphitic carbon nitride: Characterizations and their potential antibacterial/anti-biofilm applications

Abstract Nickel(ii) oxide-graphitic carbon nitride (n-NiO@g-C3N4) nanocomposite, in which nickel oxide nanoparticles (n-NiO) are anchored on the polymeric surface of graphitic carbon nitride (g-C3N4), was synthesized using the pulsed laser post processing (PLPP) in liquid medium. In the PLPP method, the precursors (NiO and g-C3N4) were simultaneously subjected to pulsed laser-induced fragmentation, and pulsed laser-induced defect engineering (anchoring of NiO on g-C3N4). To optimize the functionality of the material, n-NiO@g-C3N4 with four different mass contents of n-NiO was synthesized. The synthesized n-NiO@g-C3N4 nanocomposite and its composite partners (n-NiO and g-C3N4) were structurally, morphologically, elementally characterized by X-ray diffraction, filed emission scanning electron microscope, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses. As a first anti-microbial application, n-NiO@g-C3N4 was used to evaluate the minimal inhibitory concentration and minimal bactericidal concentration against the gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacteria. As a second anti-microbial application, the efficacy of n-NiO@g-C3N4 nanocomposite to retard S. aureus and P. aeruginosa biofilms’ growth was evaluated. It was found that for both applications, n-NiO@g-C3N4 nanocomposite exhibited an excellent anti-bacterial activity compared to pure g-C3N4.

MnCo2O4 decorated (2D/2D) rGO/g-C3N4-based Non-Enzymatic sensor for highly selective and sensitive detection of Chlorpyrifos in water and food samples

An effective and accurate detection of Chlorpyrifos (CPS), a well-known organophosphorus pesticide became essential in our modern world to control environmental pollution. Analytical detection of CPS is recommended for appropriate environmental supervision and to elude all health-related problems in smoke-stock spheres. To achieve this goal, an ecofriendly and one step combustion route for the synthesis of reduced graphene oxide-graphitic carbon nitride (rGO/g-C 3 N 4 ) 2D/2D modified manganese cobaltite (MnCo 2 O 4 ) nanocomposite was designed in this study. With the combination of properties like relatively larger surface area of rGO/g-C 3 N 4 and excellent conductivity and good biocompatibility of rGO along with MnCo 2 O 4 nanoparticles, a highly sensitive CPS sensor was aimed. The nanocomposite was identified using Powder x-ray diffraction (PXRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Raman Spectroscopy and BET analysis. In the TEM image, a distinct surface of the g-C 3 N 4 can be seen which acts as a bridge between rGO layers and MnCo 2 O 4 nanoparticles. Highest conductivity of the nanocomposite was showcased using the electronic impedance spectroscopy (EIS) technique that supported the idea of being a potential sensor material. Under optimum environment, the designed non-enzymatic electrochemical sensor was able to sense CPS at lower detection limit (LOD) of 0.14 × 10 −12 M (0.322 × 10 −6 μg/ml) with a wider range of 20 μM to 30 pM at room temperature. Furthermore, the present sensor showed desirable selectivity and superior stability with good reproducibility indicating its effective sensing capability for environmentally toxic CPS pesticide.

Highly elastic wrinkled structures for stable and low volume-expansion lithium-metal anodes

Lithium (Li) metal is promising for high energy density batteries due to its low electrochemical redox potential and high specific capacity. However, the formation of dendrites and its tendency for large volume expansion during plating/stripping restrict the application of Li metal in practical scenarios. In this work, we developed reduced graphene oxide-graphitic carbon nitride (rGO-C3N4, GCN) with highly elastic and wrinkled structure as the current collector. Lithiophilic site C3N4 in GCN could reduce the nucleation overpotential. In addition, this material effectively inhibited electrode expansion during cycling. At the same time, due to its high elasticity, GCN could release the stress induced by Li deposition to maintain structural integrity of the electrode. Li-metal anodes with GCN exhibited small volume expansion, high Coulombic efficiency (CE) of 98.6% within 300 cycles and long cycling life of more than 1700 h. This work described and demonstrated a new approach to construct flexible current collectors for stable lithium-metal anodes.

Heterostructured CuO-g-C3N4 nanocomposites as a highly efficient photocathode for photoelectrochemical aflatoxin B1 sensing

Here, copper oxide-graphitic carbon nitride (CuO-g-C3N4) nanocomposites were facilely prepared and used as an efficient photosensitive material to construct a highly sensitive photoelectrochemical (PEC) sensor. The CuO-g-C3N4 nanocomposites were directly synthesized by in-situ growth of CuO on g-C3N4 nanosheets to form p-n heterojunction. The optical absorption of CuO-g-C3N4 nanocomposites was efficaciously broadened towards visible region through CuO doping. The heterostructured CuO-g-C3N4 permitted the photogenerated electrons of g-C3N4 to transfer to CuO and meanwhile the photogenerated holes of CuO to migrate to g-C3N4 under visible light irradiation. The effective carriers generation, separation and transfer processes endows CuO-g-C3N4 nanocomposites unique and greatly enhanced cathode photocurrent response as confirmed by a series of PEC studies. Further combining with molecular imprinted polymer (MIP) which acts as a recognition unit, we construct a favorable molecular imprinted polymer photoelectrochemical (MIP-PEC) sensor with high sensitivity for target aflatoxin B1 (AFB1) detection. Under optimal conditions, the proposed MIP-PEC sensor was successfully employed for AFB1 quantitative determination with a linear range of 0.01 ng mL−1 to 1 μg mL−1 and a detection limit of 6.8 pg mL−1. In addition, the sensor has excellent selectivity under high concentrations of interfering substances circumstance. The satisfactory AFB1 recoveries in maize solution illustrated the credible application of the proposed MIP-PEC sensors for real samples, indicating promising potential in food safety control.

Physicochemical and electrochemical characterization of CdO/g-C3N4 nanocomposite for the photoreforming of petrochemical wastewater

Abstract Current research involved fabrication of cadmium oxide-graphitic carbon nitride (CdO/g-C3N4) nanocomposite and evaluation of their photocatalytic properties by physical and electrochemical analysis techniques. The X-ray diffraction (XRD) test demonstrated that the nanocomposite consists of graphite and monteponite phases. UV–Vis absorption and photoluminescence (PL) analysis clearly pointed out both the band gap reduction and inhibition in recombination rate of charge carriers. Based on the photoelectrochemical (PEC) analysis, linear sweep voltammetry (LSV) data demonstrated that CdO/g-C3N4 nanocomposite shows higher anodic current (0.57 mA/cm2) under light emission as compared to dark environment (0.02 mA/cm2). This study was also deliberated with proposed mechanism on photoreforming of wastewater reaction scheme.

Effect of Ag/ZnO-Graphitic Carbon Nitride on Antimicrobial Activity under Visible Light

Zinc oxide-graphitic carbon nitride (ZnO/g-C3N4) composites were synthesized by precipitation method in order to improve photocatalytic activity under visible light. To enhance antimicrobial activity, silver was added into zinc oxide-graphitic carbon nitride (Ag/ZnO/g-C3N4). Ultrastructures of the composite were analyzed by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). Photocatalytic activity of the composites was carried out by degradation of methylene blue solution as a function of contact time. The results revealed that ZnO/g-C3N4 was capable of dye degradation at 96.65%. Addition of Ag into ZnO/g-C3N4 resulted in increase of dye reduction rate. For antibacterial test, Ag/ZnO/g-C3N4 exhibited bactericidal activity against Pseudomonas aeruginosa and Bacillus cereus. For antifungal test, Ag/ZnO/g-C3N4 showed resistance to Aspergillusniger for 7 days. Ag/ZnO-g-C3N4 composite exhibited better photocatalytic and antimicrobial activities compare to ZnO and g-C3N4. These results indicate that precipitation method is a cheap, rapid and efficient method that can be used to synthesize Ag/ZnO-g-C3N4 composites. For further studies, applications of this Ag/ZnO-g-C3N4 composites in microbiological and agricultural fields will be carried out.

Bifunctional iron-modified graphitic carbon nitride (g-C3N4) for simultaneous oxidation and adsorption of arsenic

Iron-modified graphitic carbon nitride (FG materials) was prepared through a simple and cost-effective method using iron oxide and melamine to achieve simultaneous oxidation and adsorption of arsenic. We hypothesized that graphitic carbon nitride oxidizes As(III) to As(V) under light irradiation, and the converted As(V) is adsorbed by the amorphous iron phase on FG materials. FG materials were characterized by X-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, specific surface area, ultraviolet–visible light spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy. As(III) was efficiently transformed to As(V) due to the photocatalytic-oxidation ability of graphic carbon nitride under visible and UV light irradiation, the oxidized As(V) was adsorbed by the amorphous iron phases, and As species were removed from the system. The removal efficiency of As(III) decreased from 50%, 41%, and 33% under UV light, visible light and dark, respectively. FG materials exhibited the photocatalytic-oxidation ability and adsorption capacity, and a synergistic effect was observed between graphitic carbon nitride and iron oxide. Removal of As can be achieved even under visible light, confirming the field applicability of low-cost FG materials.

Rapid and template-free synthesis of copper(I) oxide-graphitic carbon nitride heterojunction for photocatalytic degradation of orange II dye in water

Herein, we report the synthesis of a p-n heterojunction catalyst comprising Cu2O and g-C3N4 via a novel rapid, template-free and facile one-pot approach. The pristine semiconductors and their composite were characterised by X-ray diffraction (XRD), N2 adsorption-desorption isotherms (BET), UV–vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), field emission scanning electronic microscopy (FESEM) and energy dispersive X-ray spectrometry (EDX). From the Mott-schottky plot, the flat-band potential and carrier density were estimated. Band gap energies of 2.03 and 2.65 eV were calculated for Cu2O and g-C3N4 respectively, which indicate that both catalysts possess excellent optical absorption in the visible region of the solar spectrum. The p-n heterojunction produced a type-II band alignment which promotes the efficient separation of photogenerated electron-hole pairs. The photocatalytic property of the material was evaluated by employing it for the degradation of orange II dye in water. Different mass ratios of Cu2O-g-C3N4 such as 1:1, 3:2, 7:3 and 9:1 were employed in the degradation process. However, Cu2O-g-C3N4 with mass ratio 9:1 displayed the best photocatalytic performance, giving a removal efficiency that is 3.6 times higher than the pristine Cu2O. The decolourisation and mineralisation efficiencies were 85% and 60% after 4 h of treatment. Scavenger studies further revealed the photogenerated holes as the main oxidant species in the photocatalytic reaction.

Synergistically effective and highly visible light responsive SnO2-g-C3N4 nanostructures for improved photocatalytic and photoelectrochemical performance

This paper reports the facile and scalable fabrication of mesoporous and high surface area tin oxide and tin oxide-graphitic carbon nitride nanostructures {SnO2, SnO2-C3N4 (2 mM) and SnO2-g-C3N4 (4 mM)} using a template-free hydrothermal approach. The overall characterisation revealed a high surface area (~181 m2g−1) with a mesoporous nature, relatively small particle size of SnO2 (~2–3 nm) grown successfully on g-C3N4 sheets, and significantly improved optical behaviour for visible light utilisation. Comparative screening of different SnO2-based nanostructures revealed significant improvements in visible-light induced photocatalytic degradation and photoelectrochemical performance. The visible light-induced degradation of model pollutants, such as Methylene blue (MB) and Congo red (CR), was achieved using SnO2-g-C3N4 (4 mM) with total efficiencies of ~99.38% and ~96%, respectively. The optimal SnO2-g-C3N4 (4 mM) as a photocatalyst showed first order rate constants for MB and CR degradation of 6.39 × 10−2 min−1 and 2.9 × 10−2 min−1, respectively. Moreover, the investigation of different modified photoelectrodes of SnO2-g-C3N4 (4 mM) and SnO2-g-C3N4 (2 mM) show more than eight and five times higher photoelectrochemical performance than that of SnO2, respectively. The possible synergistic effect makes the SnO2-g-C3N4 (4 mM) nanostructure an exceptional photocatalytic and photoresponsive material under visible light that can be used for future environmental and energy-related purposes.

Synthesis of BaWO4/NRGO–g-C3N4 nanocomposites with excellent multifunctional catalytic performance via microwave approach

Novel barium tungstate/nitrogen-doped reduced graphene oxide-graphitic carbon nitride (BaWO4/NRGO-g-C3N4) nanocomposite has been synthesized by a simple one-pot microwave technique. The synthesized nanocomposites are well characterized by diffraction, microscopic and spectroscopic techniques to study its crystal structure, elemental composition, morphological features and optical properties. The material prepared is tested for its performance as an electrocatalyst, photocatalyst and reduction catalyst. The nanocomposite catalyzed the photodegradation of methylene blue (MB) dye in 120 min, reduction of 4-nitro phenol (4-NP) to 4-amino phenol (4-AP) in 60 s, showed an impressive Tafel slope of 62 mV/dec for hydrogen evolution reaction (HER). The observed results suggest that the nanocomposite acts as an efficient multifunctional catalyst. The reported approach provides fundamental insights which can be extended to other metal tungstate-based ternary composites for applications in the field of clean energy and environment in the future.

Zinc oxide-graphitic carbon nitride nanohybrid as an efficient electrochemical sensor and photocatalyst

In this study, zinc oxide-graphitic carbon nitride (ZnO-CN) nanohybrid has been synthesized via a facile in-situ one pot solid-state thermal decomposition method, here [Zn(hmp-H)2(H2O)(μ-Cl)Zn(μ-Cl)(Cl)3] was used as single-source molecular precursor (SSMP) for ZnO and urea was taken as a source for graphitic carbon nitride (CN). Synthesized ZnO-CN nanohybrid was used as a modifier towards the fabrication of a binder free glassy carbon electrode surface (ZnO-CN/GCE) for detection of –NO2 containing aromatic compounds. The developed sensor shows the remarkable sensitive lower detection limit responses of 100 nM, 110 nM, 202 nM towards the 4-nitrotoluene (4-NT); 2,4-dinitrotuluene (2,4-DNT); 2,4,6-trinitrophenol (2,4,6-TNP), respectively. Further, a superior and rapid photo-catalytic degradation of Chicago Sky Blue (CSB), Congo Red (CR) and Methylene Blue (MB) was also achieved by employing ZnO-CN as a photo-catalyst with the percentage degradation of ∼85-99.6%. The alluring performance of the ZnO-CN nanohybrid towards the sensing of -NO2 containing aromatics and degradation of organic pollutants was ascribed to high surface area of as synthesized nanohybrid and heterojunction formed between the interfaces of ZnO and graphitic carbon nitride. These properties may facilitate the electron transfer process due to the higher electron conductivity and the separation of photo-induced electron−hole pairs.

In situ growth of copper oxide-graphite carbon nitride nanocomposites with peroxidase-mimicking activity for electrocatalytic and colorimetric detection of hydrogen peroxide

This study reported a facile approach for the preparation of copper oxide-graphitic carbon nitride nanocomposites by an in situ growth method in aqueous solution. The powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and atomic force microscopy characterizations of the copper oxide-graphitic carbon nitride nanocomposites suggest that we have successfully synthesized a novel nanozyme. The nano-sized of copper oxide nanoparticles embedded in graphitic carbon nitride nanoparticles were evaluated focusing on the principle of horseradish peroxidase-like activity catalyzing the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine in the presence of hydrogen peroxide. Furthermore, we constructed dual sensor platforms based on copper oxide-graphitic carbon nitride nanocomposites. By constructing an electrochemical platform and a colorimetric sensor to detect hydrogen peroxide, it is shown that copper oxide-graphitic carbon nitride nanocomposites had an excellent peroxidase mimicking catalytic performance. We envision that our nanozyme have great potential in a variety of applications in catalytic field, electrochemical sensing, optical imaging, and environmental assay.