Graphitic Carbon Research Articles

Enabling highly concentrated tetracycline degradation with tailored FeCo nanocrystals in porous graphitic carbon fiber

Enabling highly concentrated tetracycline degradation with tailored FeCo nanocrystals in porous graphitic carbon fiber

Efficient uranium removal by amidoxime functionalized graphitic carbon nitride and its potential mechanism

Efficient uranium removal by amidoxime functionalized graphitic carbon nitride and its potential mechanism

Adsorption performance of g-C3N4/graphene, and MIL-101(Fe)/graphene for the removal of pharmaceutical contaminants: a molecular dynamics simulation study

The rising presence of drug-related contaminants in water sources is a major environmental and public health concern. Several studies have addressed the hazardous influence of these pollutants on the lives of over 400 million people worldwide. In this study, we used molecular dynamics simulations to evaluate the efficacy of two promising composite materials for the removal of pharmaceutical contaminants by using the adsorption technique. Graphitic carbon nitride/graphene (g-C3N4/graphene) and metal-organic framework (MIL-101(Fe))/graphene have been simulated for the first time for the removal of three of the most common pollutants (acetaminophen (AC), caffeine (CAF), and sulfamethoxazole (SMZ)). The nanocomposite structure has been created and optimized using the geometry optimization task in the DFTB Modules in the Amsterdam Modeling Suite. We summarized the condition of the essential parameters (Temperature, pressure, and density) of the simulation box during the MD-simulation to ensure the accuracy of our MD-simulation results. The adsorption process, van der Waals interactions, and the adsorption capacity have been calculated by using the Reactive Forcefield (ReaxFF) software. We found that the combination of MIL-101(Fe)/graphene had a higher adsorption capacity for the removal of pharmaceutical contaminants than g-C3N4/graphene. At 40 Picosecond (Ps), 80 molecules of each pharmaceutical contaminants (AC, CAF and SMZ) have been adsorbed by MIL-101(Fe)/graphene with higher exothermic energy equated to (−1174, −1630, and − 2347) MJ/mol respectively. While for g-C3N4/graphene at 40 Ps, 70 molecules of each pharmaceutical contaminants have been adsorbed with exothermic energy equated to (−924, −966, and − 1268) MJ/mol respectively. Also, our results showed that the combination of g-C₃N₄/graphene and MIL-101(Fe)/graphene both have remarkable properties that make them effective at resisting surface clogging. Finally, the results showed that the adsorption kinetics followed a pseudo-first order model, while the adsorption isotherms for AC, CAF and SMZ adhered to Freundlich model.

A High-Performance and Flexible Electrothermal Heater with Bending Tolerance from Layer-by-Layer Self-Assembled Graphite Nanoplates and Carbon Black on Paper

A High-Performance and Flexible Electrothermal Heater with Bending Tolerance from Layer-by-Layer Self-Assembled Graphite Nanoplates and Carbon Black on Paper

NiPd Nanoparticles on Nanoporous Carbon Embedded in Graphitic Carbon Nitride for Transfer Hydrogenation and Suzuki–Miyaura Coupling Reactions

NiPd Nanoparticles on Nanoporous Carbon Embedded in Graphitic Carbon Nitride for Transfer Hydrogenation and Suzuki–Miyaura Coupling Reactions

A Well‐Coupled Supramolecular System Accelerates Photophosphorylation

AbstractSupramolecular assembly allows multiple chemical/bio‐components integrated as one system for cascade biochemical reactions. Herein the graphitic carbon nitrides (g‐C3N4) as photocatalyst trapped in a dipeptide hydrogel covering adenosine triphosphate (ATP) synthase accelerates the photophosphorylation through ATP synthesis. Self‐assembled N‐fluorenylmethoxycarbonyl diphenylalanine (Fmoc‐FF) as nanofibrils to allow g‐C3N4 nanosheets are embedded as a complex Fmoc‐FF/g‐C3N4 hydrogel. Fmoc‐FF gel exhibits good electronic coupling with g‐C3N4, which enables a photo‐induced proton generation. The transmembrane proton gradient can be established by ATP synthase‐lipid reconstituted on the surface of the Fmoc‐FF/g‐C3N4 hydrogel to enhance the ATP synthesis. It indicates that the Fmoc‐FF/g‐C3N4/ATP synthase‐lipid film can possess a longer‐term ATP production capability and allow repeated immersion for sustained ATP production. Such a hydrogel‐supported ATP synthesis platform is achieved by a procedure at a larger scale.

Development of engineered Zn-MOF/g-C3N4 based photoelectrochemical system for real-time sensors and removal of naproxen in wastewater

Naproxen-contaminated water may lead to the accumulation of the drug in aquatic organisms and can pose high risks to an aquatic environment and human beings. Therefore, this work aimed to develop photoelectrochemical sensing and degradation of naproxen (NPX) using zinc-metal organic framework /graphitic carbon nitride thin film-based fluorine-doped tin oxide (Zn-MOF/g-C3N4/FTO) as anode material for the sensing and degradation of naproxen (NPX). The surface morphology, structure, surface property, surface area, optical property, photocurrent, and charge transfer kinetics abilities were studied using different techniques. The nanocomposites showed a superior photocurrent response (0.815 mA cm-2) compared to the original g-C3N4 (0.328 mA cm-2). The photo-anode made of Zn-MOF@g-C3N4/FTO displayed the highest photocurrent value, indicating that the alignment of the two semiconductor bands prevented the quick recombination of electron-hole pairs. Owing to these attractive features, the Zn-MOF/g-C3N4/FTO electrode was applied for photoelectrochemical detection of NPX using chronoamperometry. Interestingly, the nanocomposites-based FTO ascribed a lower detection limit (2.3 ng l-1) with a wide linear range concentration of NPX (0.5 to 200 µg l-1). Additionally, the analytical assessment of repeatability and reproducibility demonstrated robust performance, with commendable relative standard deviations (RSD%) of 2.54 % and 2.40 %, respectively. On the other hand, a remarkable degradation efficiency of 97.52 % was attained when employing a bias potential of 0.1 V during a 2 h photoelectrocatalytic oxidation of NPX. The degradation process was primarily driven by the active participation of holes and hydroxyl radicals in ring opening and subsequent cleavage of by-products. The notable effectiveness of this degradation can be attributed to the combined and synergistic effects of both electrochemical and photocatalytic degradation techniques. The current state demonstrates its effectiveness in the photoelectrochemical sensing and removal of NPX using MOF/g-C3N4 nanocomposites-based electrode materials in wastewater.

Oxygen-Doped Porous Ultrathin Graphitic Carbon Nitride Nanosheets for Photocatalytic Hydrogen Evolution and Rhodamine B Degradation.

Graphite phase carbon nitride (g-C3N4) is a highly promising metal-free photocatalyst, but its low activity, due to limited quantum efficiency and small specific surface area, restricts its practical application. While exfoliating bulk crystals into porous thin-layer nanosheets and incorporating dopants have been shown to improve photocatalytic efficiency, these methods are typically complex, time-consuming, and costly processes. In this study, we developed a simple approach to synthesize oxygen-doped porous g-C3N4 (OCN) nanosheets. The resulting OCN exhibited significantly enhanced light absorption and visible-light photocatalytic activity compared to bulk g-C3N4 (BCN) and g-C3N4 (CN). The OCN achieved an impressive hydrogen evolution reaction (HER) rate of 8.02 mmol g-1 h-1, eight times greater than BCN, and demonstrated a high Rhodamine B (RhB) degradation rate of 97.3 % owing to the generation of abundant singlet oxygen. These improvements in photocatalytic performance are attributed to the narrow band gap and enhanced electron transfer properties, suggesting a promising route for the efficient design of g-C3N4-based photocatalysts.

Polarized electric field-mediated graphitic carbon nitride-based S-scheme heterostructure for efficient photocatalytic removal of bisphenol A

Tuning interface charge transfer is considered as a feasible way to promote electron migration and separation in heterojunction system, but the role of in-plane electron behavior in single phase has received little attention. Here, a carboxyl functionalized graphitic carbon nitride (CCN) coupled PbBiO2Br (PBOB) S-scheme heterostructure is elaborately designed for investigation. Compared with pristine CN/PBOB, although the existence of carboxyl group weakens the built-in electric field strength of CCN/PBOB (ΔΦ = 0.44 eV), the formed polarized electric field (µ = 3.18 Debye) is conducive to the pre-separation of photogenerated electrons and holes in CCN, thereby improving interface charge transfer. In addition, the introduced carboxyl group can also serve as an O2 adsorption site to enhance its activation, and generate reactive oxygen species (ROS) through a two-step single-electron O2 reduction route. Thus, the optimized CCN/PBOB exhibits excellent photocatalytic ROS generation ability, which can remove 88.7 % of bisphenol A and significantly reduce the acute toxicity of the formed intermediates. This work provides a new perspective for the development of advanced heterojunction photocatalyst by regulating in-plane/interface charge dynamics, and helps to fully understand the pollutant detoxification/degradation process initiated by molecular oxygen activation.

Surface Coordination Chemistry of Graphitic Carbon Nitride from Ag Molecular Probes.

Graphitic carbon nitride (g-C3N4) has gained significant attention for its catalytic properties,especiallyin the development of Single Atom Catalysts (SACs).However,the surface chemistry underlying the formation of these isolated metal sites remains poorly understood.In thisstudyweemploy Surface OrganoMetallic Chemistry (SOMC) together with advanced microscopic and spectroscopic techniquesfor an in-depth analysis of functionalizedg-C3N4materials, where tailored organosilver probe molecules are used to monitor surface processes and characterize resulting surface species. Amulti-technique approach-including high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM), X-ray absorption spectroscopy (XAS), and multinuclear solid-state Nuclear Magnetic Resonance spectroscopy (ssNMR),coupled with density functional theory (DFT) calculations- identifies three primary surface speciesin Ag-functionalized g-C3N4:bis-NHC-Ag+, dispersed Ag+sites, andphysisorbed molecular precursor.These findings highlight a dynamic grafting process and provide insights into the surface coordination chemistryof functionalizedg-C3N4materials.

Graphitic carbon nitride-modified cerium ferrite: an efficient photocatalyst for the degradation of ciprofloxacin, ampicillin, and erythromycin in aqueous solution

Incomplete removal of antibiotics by most known wastewater treatment plants is a global challenge. Therefore, graphitic carbon nitride-modified cerium ferrite (CeFe2O4@g-C3N4) was synthesized to remove antibiotics (ampicillin, ciprofloxacin and erythromycin) from water. CeFe2O4@g-C3N4 showed activity in the visible light with a Tauc plot revealing the bandgap energy (2.46 eV). The scanning electron micrograph (SEM) result revealed the surface of CeFe2O4@g-C3N4 to be heterogeneous, while the transmission electron micrograph (TEM) image confirmed a flaky with rod and oval shaped surface (average particle size of 42.22 nm). CeFe2O4@g-C3N4 exhibited a 100% removal of all the studied antibiotics from aqueous solution in a photocatalytic degradation that is described by pseudo-1st-order kinetics. CeFe2O4@g-C3N4 demonstrated a high regeneration capacity, which is above 90% at the 12th cycle of treatment without any observable changes in its phase structure which suggests a promising chemical stability and reusability. CeFe2O4@g-C3N4 compared favourably with some selected antibiotic degradable photocatalysts suggesting the economic viable of CeFe2O4@g-C3N4 as photocatalyst for the purification of antibiotics-contaminated water.Graphical

Visual aptasensor based on PtNPs/g-C3N4 and DNase I for the field detection of acetamiprid.

A visual aptasensor based on the combination of graphitic carbon nitride loaded with platinum nanoparticles (PtNPs/g-C3N4) and deoxyribonuclease I (DNase I) was developed for detecting acetamiprid. The prepared PtNPs/g-C3N4 exhibited excellent peroxidase (POD)-like activity, demonstrating the capacity to oxidize the colourless o-phenylenediamine (OPD) to produce the coloured product diaminophenazine (DAP) in the presence of hydrogen peroxide (H2O2). The DNA aptamer of acetamiprid can adsorb onto the surface of PtNPs/g-C3N4, thereby inhibiting its POD activity. The binding of acetamiprid to its aptamer results in the aptamer desorbing from the surface of PtNPs/g-C3N4 and subsequent digestion by DNase I. Ascribed to the synergistic effect of these factors, the aptasensor can achieve the rapid on-site detection of acetamiprid based on the acetamiprid-induced the colour change of the solution just with the smartphone. Furthermore, due to the remarkable fluorescence signal of DAP at 570nm, the aptasensor under fluorescence mode enables highly sensitive and quantitative detection of acetamiprid with a linear range of 1 ng/mL to 4µg/mL and a detection limit as low as 0.31 ng/mL.Theaptasensor has successfully realized the detection of acetamiprid in river water and cucumber samples, offering a novel perspective for the rapid assessment of environmental pollution and food safety risks associated with acetamiprid residues.

Self-Assembly Synthesis of Oxygen and Sulfur Co-Doped Porous Graphitic Carbon Nitride Nanosheets for Boosting CO2 Photoreduction.

Graphitic carbon nitride (CN) has garnered considerable attention in the field of visible-light CO2 photoreduction, but its efficiency remains limited by the intrinsic π-conjugated skeleton. Here, O and S were co-doped CN (O, S/CN) by a facile "hydrolysis + calcination" approach to modulate the physicochemical and electronic structure. Distinctive from S doped CN (SCN), O, S/CN owned porous layer structure with several nanosheets and less SO4 2- groups on the surface. The amount of heteroatom-doping was achieved by changing the hydrothermal temperature. The optimum O, S/CN-80 achieved moderate CO production rate of 1.29 μmol g-1 h-1, which was 3.79 times as much as SCN (0.34 μmol g-1 h-1). The O and most S atoms were substitutionally doped and the effect of S doped state on the improved efficiency of CO generation in O, S/CN was also explored based on the theoretical calculations. This work provides an inspiration to develop efficient dual-doped CN photocatalysts for photocatalytic CO2 reduction.

Z-Scheme Enabled 1D/2D Nanocomposite of ZnO Nanorods and Functionalized g-C3 N4 Nanosheets for Sustainable Degradation of Terephthalic Acid.

The urgent need to mitigate water pollution and achieve Sustainable Development Goal 14 (SDG 14)-Life below water, necessitates developing efficient and eco-friendly wastewater treatment technologies. This research addresses this challenge by photocatalytic degradation of terephthalic acid, a precursor for PET bottles using environment-friendly and biocompatible photocatalysts. The 1D/2D nanocomposite comprising zinc oxide (ZnO) nanorods and functionalized graphitic carbon nitride (Zn-TG) nanosheets were synthesized and thoroughly characterized. The nanocomposite effectively mitigated the individual drawbacks of Zn-TG agglomeration and the wide band gap of ZnO as confirmed through zeta potential and Tauc's plot studies, respectively. The synthesized nanocomposite achieved ~100 % degradation within 60 minutes, exhibiting superior kinetics (~2.5 times) compared to pristine samples. The enhanced degradation efficiency was elucidated by efficient charge carrier transfer (~5 times faster) and separation (~2 times improved) as confirmed through electrochemical impedance spectroscopy and time-resolved photoluminescence studies. The proposed Z-scheme pathway provides mechanistic insights. This proposed mechanism is supported by extensive electron paramagnetic resonance (EPR) and scavenger studies. The liquid chromatography-mass spectrometry (LC-MS) analysis confirms the formation of less toxic byproducts for ensuring that the wastewater treatment process is efficient and environmentally friendly. This research helps in developing a highly effective and sustainable wastewater treatment technology.

Catalytic hydrogenation of CO2 by composite nickel species supported on KCl-doped graphitic carbon nitride under normal temperature and atmospheric pressure

CO2 can be used as a cheap C1 feedstock to produce value-added chemical products and fuels. In this work, it was proposed for the first time that potassium chloride-doped graphitic carbon nitride-supported composite nickel species (CNS/KCl-g-C3N4) was prepared to catalyze CO2 hydrogenation with potassium borohydride (KBH4) as a hydrogen donor to produce formate at normal temperature and atmospheric pressure. The catalytic activity of CNS/KCl-g-C3N4 reached the best when the nickel loading was optimized as 15 wt%. By using CNS/KCl-g-C3N4, the hydrogen production volume and rate of KBH4 hydrolysis were reduced by 49 % and 32 %, respectively, while the formate concentration was increased by 43 %. It was speculated that the catalytic hydrogenation of CO2 was enhanced due to the chemical adsorption of CO2 on the catalyst surface by interacting with the K-N bonds and -NH2 groups, and the formation of BH4-n(OH)n- (n=0–3) with higher activity from BH4- on the Ni0 sites.

Theoretical Study of the Magnetic Mechanism of a Pca21 C4N3 Monolayer and the Regulation of Its Magnetism by Gas Adsorption

For metal-free low-dimensional ferromagnetic materials, a hopeful candidate for next-generation spintronic devices, investigating their magnetic mechanisms and exploring effective ways to regulate their magnetic properties are crucial for advancing their applications. Our work systematically investigated the origin of magnetism of a graphitic carbon nitride (Pca21 C4N3) monolayer based on the analysis on the partial electronic density of states. The magnetic moment of the Pca21 C4N3 originates from the spin-split of the 2pz orbit from special carbon (C) atoms and 2p orbit from N atoms around the Fermi energy, which was caused by the lone pair electrons in nitrogen (N) atoms. Notably, the magnetic moment of the Pca21 C4N3 monolayer could be effectively adjusted by adsorbing nitric oxide (NO) or oxygen (O2) gas molecules. The single magnetic electron from the adsorbed NO pairs with the unpaired electron in the N atom from the substrate, forming a Nsub-Nad bond, which reduces the system’s magnetic moment from 4.00 μB to 2.99 μB. Moreover, the NO adsorption decreases the both spin-down and spin-up bandgaps, causing an increase in photoelectrical response efficiency. As for the case of O2 physisorption, it greatly enhances the magnetic moment of the Pca21 C4N3 monolayer from 4.00 μB to 6.00 μB through ferromagnetic coupling. This method of gas adsorption for tuning magnetic moments is reversible, simple, and cost-effective. Our findings reveal the magnetic mechanism of Pca21 C4N3 and its tunable magnetic performance realized by chemisorbing or physisorbing magnetic gas molecules, providing crucial theoretical foundations for the development and utilization of low-dimensional magnetic materials.

Pd-Co₃O₄/Acetylene Black Nanocomposite as an Efficient and Robust Bifunctional ORR/OER Electrocatalyst for Rechargeable Zinc-Air Batteries

Developing cost-effective and high-performing bifunctional electrocatalysts is pivotal for advancing rechargeable zinc-air batteries (ZABs). In this study, a Pd-Co₃O₄ loaded on acetylene black (Pd-Co₃O₄/C) electrocatalyst was developed with excellent properties for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) using reduced H₂PdCl₄ to modify Co₃O₄/C. The experimental findings indicate that the Pd-Co₃O₄/C electrocatalyst exhibits a favorable half-wave potential for ORR at 0.91 V, a feasible potential for OER at 1.48 V (measured at 10 mA/cm2), also minor Tafel slopes for both ORR (44.65 mV/dec) and OER (58.41 mV/dec). Additionally, it evidences a power density of 186 mW/cm2 in ZABs and good durability during galvanostatic charge-discharge cycling. The impressive performance of Pd-Co₃O₄/C can be ascribed primarily to the beneficial synergistic effect resulting from the composition of Co₃O₄ and Pd embedded within graphite carbon. This research lays the groundwork for the expansion of additional cost-effective and highly effective electrocatalysts in the coming years.

Film-immobilized carbon nitride for the degradation of pharmaceuticals: A continuous flow photoreactor performance upheld by excitation-emission matrix fluorescence spectroscopy

The validation of immobilized photocatalysts is a fundamental matter regarding the scaling-up process in the photocatalytic degradation of aqueous pollutants in natural surface waters. This work presents the comprehensive evaluation of graphitic carbon nitride (g-C3N4, CN) immobilized onto a polymeric film (F) placed inside a continuous flow operation planar reactor for the removal of a mixture of pharmaceuticals (i.e., venlafaxine, citalopram, carbamazepine, tramadol, ketoprofen, and diclofenac, 3 μM each) under visible light. The resulting CN/F (8 mg of CN per cm2 of film and with significant preservation of optical and structural properties after more than 350 h of reuse) yielded the complete removal under total recirculation of all pharmaceuticals after 90 min under visible light, except for ketoprofen, probably ascribed to competition for photogenerated holes, as suggested by the proposed mechanism. Under dead-end continuous flow mode, the steady-state conversion averaged 67 % in deionized water, increasing up to 76 %, and 80 % in natural surface waters obtained from the Douro River and the effluent from a wastewater treatment plant (Northwestern Portugal), respectively, related to the promotion effect of carbonates anions and organic matter. The assessment of excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor (PARAFAC) analysis further demonstrated the removal (ca. 50 %) of the protein- and humic-like substances contained in the collected wastewater, thus evidencing the continuous flow mode performance of the immobilized photocatalyst for real environmental applications.

Novel N-doped carbon nanotubes impregnated Mn spheres with polydopamine coating as an efficient polysulfide immobilizer for Li-S batteries

Lithium-sulfur (Li-S) batteries are one of the most promising energy storage and conversion devices due to the high theoretical capacity and cost-effectiveness of sulfur. However, they still suffer from sluggish redox kinetics and the shuttle effect caused by complex polysulfides. In this work, graphitic carbon nitride (g-C3N4) is utilized as a template and further hydrothermally treated with an Mn source and glucose. The pyrolysis of g-C3N4 gives rise to N-doped carbon nanotubes, producing abundant sites for physical confinement and chemical adsorption of polysulfides, while glucose carbonization brings forth amorphous carbon and Mn source produces metal spheres. Afterward, polydopamine (PDA) induces N-doped carbon coating and promotes interface connection as well as electron immigration. This synergistic design possesses a high surface area of micropores and mesopores to aggregate sulfur and accelerate redox kinetics. As a result, the N-doped carbon nanotube with Mn spheres and PDA coating@sulfur (CN/Mn-PDA@S) exhibits a high reversible capacity of 813.5 mAh g−1 at 1 C with a decay rate of 0.064% per cycle and remarkable capacity retention at 2 C with rate performance up to 4 C. Therefore, the novel design of N-doped carbon nanotubes with Mn spheres and PDA coating serves as an efficient polysulfide immobilizer for Li-S batteries.

Bio-inspired synthesis of Ag-g-C3N4 nanocomposites and their application for photocatalytic degradation of para-nitrophenol

Nanocomposites are promising in advanced materials for environmental applications due to their ability to boost functionality through synergistic effects. Graphitic carbon nitride (g-C3N4) is renowned for its exceptional characteristics in photocatalysis. This work examines the preparation of g-C3N4 from different precursors, and how the presence of silver nanoparticles (Ag NPs) and silver ions (Ag+) in g-C3N4 matrices improve their combined effect on photocatalytic activity, specifically in the degradation of para-nitrophenol (PNP), a persistent organic pollutant. From urea and melamine precursors for the preparation of g-C3N4, the latter provided a much higher yield. Using an easy synthesis approach, Ag NPs were evenly distributed in the g-C3N4 framework, whereas Ag+ ions were incorporated by an apparent physical procedure. A bio-inspired, environmentally friendly method was also applied to prepare Ag NPs. The nanocomposites showed improved light absorption and separation of charge carriers due to the synergistic interaction between g-C3N4 and Ag species. Using UV and Vis LED light sources, we investigated both pure g-C3N4 and Ag-g-C3N4 catalysts. For breaking down para-nitrophenol, the silver-modified catalysts performed significantly better than pure g-C3N4 in both UV and Vis. The study clarified the functions of Ag NPs and Ag+ ions in enhancing photocatalytic activity by examining their involvement in generating reactive oxygen species and degrading pollutants. This work highlights the capability of g-C3N4-based nanocomposites as effective photocatalysts for environmental remediation. It also explores the benefits of adding silver species to improve performance in degrading pollutants.