Graphitic Carbon Research Articles

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.

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.

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.

Graphitic carbon nitride nanosheets decorated with HAp@Bi2S3 core–shell nanorods: Dual S-scheme 1D/2D heterojunction for environmental and hydrogen production solutions

By combining different semiconductors, scientists have developed innovative materials capable of converting solar energy into useful forms of energy or driving chemical reactions that clean up pollutants. These materials offer a promising path to combat global environmental and energy challenges. In this study, HAp@Bi2S3 core–shell structures were synthesized using a facile microemulsion technique, and then loaded onto graphitic carbon nitride via a hydrothermal method to create an advanced HAp@Bi2S3/g-C3N4 dual S-scheme heterojunction. The engineered heterojunction exhibited enhanced hydrogen production and visible light photocatalytic oxidation of metronidazole. The improved photocatalytic efficiency was attributed to the core–shell structure of HAp@Bi2S3 along with the formation of a dual S-scheme heterojunction in HAp@Bi2S3/g-C3N4. As a result, the novel dual S-scheme HAp@Bi2S3/g-C3N4 heterojunction demonstrated a significantly higher hydrogen production rate, ca. 20 times higher than that of hydroxyapatite (HAp), 11 times higher than Bi2S3, and 5 times higher than the HAp@Bi2S3. This research introduces a novel approach to crafting dual S-scheme heterojunctions based on Bi2S3, which enables swift electron transfer across heterojunction interfaces, thereby enlarged possibility windows to sustainable hydrogen production and wastewater remediation technologies.

Innovative synthesis and practical application of graphitic carbon nitride/α-zirconium phosphate in visible light-activated Knoevenagel condensation

Innovative synthesis and practical application of graphitic carbon nitride/α-zirconium phosphate in visible light-activated Knoevenagel condensation

Construction of calcium zirconate nanoparticles confined on graphitic carbon nitride: An electrochemical detection of diethofencarb in food samples

Construction of calcium zirconate nanoparticles confined on graphitic carbon nitride: An electrochemical detection of diethofencarb in food samples

Synergistic Role of Indium Doping and g-C3N4 Reinforcement in Boosting the Visible Light-Triggered Rhodamine B and Diclofenac Sodium Salt Degradation over Rare Earth Molybdate

Designing and fabricating cost-efficient and eco-friendly photocatalysts for removing organic pollutants from wastewater streams is a crucial research objective for effectively managing industrial effluents to tackle environmental sustainability issues. In this study, we prepared bare cerium molybdate (Ce2(MoO4)3, M1) and indium-doped cerium molybdate (In- Ce2(MoO4)3, M2) photocatalysts via a hydrothermal method. We then synthesized a nanocomposite of In- Ce2(MoO4)3 (M3) with the promising material graphitic carbon nitride (g-C3N4) using an ultrasonication approach. The synthesized photocatalysts were effectively applied to degrade the Rhodamine B dye and diclofenac sodium salt (a drug) from synthetic industrial wastewater through a photocatalysis approach. The impact of indium (In3+) doping on the bare (Ce2(MoO4)3 and the strong interaction between the (In-Ce2(MoO4)3 and g-C3N4 nanosheets were analyzed through physical and electrochemical techniques, including SEM, EDS, XRD, FTIR, UV-Vis spectroscopy, and EIS analysis. The comprehensive photocatalytic degradation of dye and the drug via first-order kinetic parameters under visible light irradiation for all the prepared catalyst samples was evaluated. The nanocomposite In-Ce2(MoO4)3/g-C3N4 exhibited excellent photocatalytic activity, degrading the maximum amount of RhB dye and drug (RhB:96%, drug:87%) in 90 minutes with a higher rate constant (k) compared to In-Ce2(MoO4)3 (RhB:69%, drug:56%) and Ce2(MoO4)3 (RhB:56%, drug:38%). Furthermore, the In-Ce2(MoO4)3/g-C3N4 samples produced a 7-fold and 3-fold increase in transient photogenerated current response compared to pristine Ce2(MoO4)3 and In-Ce2(MoO4)3 samples, respectively. These findings pave the way for synthesizing an economical, versatile, and efficient In-Ce2(MoO4)3/g-C3N4 photocatalyst to eliminate pollutants from industrial wastewater streams and boost environmental sustainability.

Interfacial adsorption of ionic liquids (ILs) on graphitic carbon nitride (g-C3N4) nanosheets: A DFT study

Interfacial adsorption of ionic liquids (ILs) on graphitic carbon nitride (g-C3N4) nanosheets: A DFT study

G-C3N4 coupled with GO accelerates carrier separation via high conductivity for photocatalytic MB degradation

Graphitic carbon nitride (g-C3N4) is widely utilized in photocatalysis due to its responsiveness to visible light, low cost, and non-toxicity. However, its efficiency is limited by factors such as the rapid recombination of photogenerated electron-hole pairs, slow electron transfer rates, and a limited number of active surface sites. In this study, g-C3N4 was synthesized through thermal polymerization, and varying amounts of graphene oxide (GO) were incorporated via physical blending to fabricate composite photocatalysts. The results indicated that the incorporation of GO not only increased the specific surface area and modified the pore size distribution of g-C3N4 but also affected the heptazine ring structure through chemical bonding, thereby enhancing the density of active sites. Photocatalytic degradation experiments with methylene blue (MB) indicated that g-C3N4 containing 2% GO exhibited photocatalytic activity 2.84 times greater than that of pristine g-C3N4. Kinetic simulations indicated that the Kapp value for the 2% GO-g-C3N4 composite was 0.00469min-1, which is 4.34 times higher than that of pure g-C3N4 (0.00108min-1). Furthermore, this composite maintained high photocatalytic activity after four cycles of reuse. An analysis of the photocatalytic degradation mechanism revealed that the incorporation of GO effectively promoted the separation and transfer of photogenerated electron-hole pairs, enhanced photocurrent density, and improved carrier separation efficiency. Electron spin resonance (ESR) and free radical scavenging experiments confirmed that the primary active species involved in the degradation of MB by the composite photocatalyst were ·O2- and h+. This study presents a novel approach for enhancing the photocatalytic performance of g-C3N4 by modifying its electronic structure and surface properties.

G-C3N4 based Z-scheme photocatalysts for tetracycline degradation: A Comprehensive Review

Graphitic carbon nitride (g-C3N4) has garnered significant attention due to its low cost, ease of preparation, high chemical stability, and non-toxicity. Nevertheless, pristine g-C3N4 faces challenges in simultaneously achieving a broad absorption range, high stability, efficient charge separation, and strong redox capability, which hampers its practical applications. Recently, g-C3N4-based Z-scheme photocatalysts have emerged as research hotspots owing to their robust redox ability, effective charge carrier separation, and capacity to harness visible light for degradation of tetracyclines (TCs) in waters. This review delves into the fundamental photocatalysis, and application of g-C3N4-based Z-scheme photocatalysts for the degradation of TCs pollutants. The review concludes with final remarks and a concise discussion on the prospects of g-C3N4-based Z-scheme photocatalysts.

Analysis of interlayer dependency of MoS2/g-C3N4 heterostructure as an anode material for sodium-ion batteries

In this present work, we explore the effectiveness of layered molybdenum disulfide (2H-MoS2) and graphitic carbon nitride (g-C3N4) heterostructure as anode for Sodium-Ion Batteries (SIBs) by using first principles analysis. To study the anode properties, we varied the interlayer distance between 2H-MoS2/g-C3N4 as 3Å, 6Å, 9Å,12 Å, and 14 Å between MoS2 as substrate and g-C3N4 as top layer. The fundamental properties, such as structural stability and electronic structure were analysed for the respective systems. The adsorption kinetics of Na ion on the g-C3N4 layer were analysed by performing molecular dynamics (MD) simulations to understand the adsorption mechanism better. Our results showed that the interlayer distance of 6 Å with formation energy of −4.31 eV, the theoretical specific capacity value of 765.32 mAhg−1, the average electrode potential is between 0.8 and 1.3 V and the adsorption energy of −2.16 eV is suitable for MoS2/g-C3N4 based anodes for Na ion batteries.

Fe-N catalyst derived from and supported on Lycopodium clavatum sporopollenin exine capsules for the oxygen reduction reaction

A carbon-supported electrocatalyst, featuring carbon nanotubes anchored on 3D porous graphitic carbon, was developed with the aim to perform in the operating conditions of alkaline fuel cells and metal air batteries. The catalyst was developed via two steps: first powders of Sporopollenin exine capsules used as a bio-based carbon support were activated via CO2 gasification to obtain a high specific area and porosity, second the derived porous carbons were impregnated by an iron salt and a nitrogen source, to be carbonised in Nitrogen at high temperature. The prepared catalyst demonstrated an efficient oxygen reduction reaction activity showing a half-wave potential of ~ 0.775 V vs. Reversible hydrogen electrode, comparable with that of commercial 20 wt% Pt/C in alkaline conditions, a good stability after accelerated degradation testing, retaining ~ 86% of the initial limiting current density, and a higher diffusion limited current density (6.3 vs. 5.1 mA cm− 2) than the commercial counterpart. Overall, we show the suitability of Sporopollenin exine capsule as support for electrocatalysis and a promising methodology to develop sustainable catalysts for the oxygen reduction reaction.

High-performance supercapacitor of ZnO-incorporated structurally modified g-C3N4 with circular mesoporous channels attained via a template-free approach

Abstract Here, the superior structural features of graphitic carbon nitride (g-C3N4) in combination with integrated mesoporous channels have been explored for its use as a supercapacitor electrode material. A facile template-free strategy is adopted for the preparation of ZnO-incorporated modified g-C3N4 nanocomposite, where material characterization via x-ray difraction, Fourier transfrom infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy analysis revealed the presence of structurally modified g-C3N4 having uniform circular mesoporous channels with well-dispersed ZnO with strong Zn–C and Zn–N interactions. The electrical double-layer capacitance together with the pseudocapacitance of the ZnO/g-C3N4 electrode material resulted in improved performance, leading to a specific capacitance of 146.3 F g−1 at a current density of 0.5 A g−1; an increased capacitance is observed in 5000 repeated charge–discharge cycles. A symmetric coin cell supercapacitor fabricated from the material displayed an energy density of 38.8 mWh kg−1 at a power density of 4259 mW kg−1. Additionally, the long life of 6000 cycles (retaining 100% specific capacitance) exhibited by the coin cell supercapacitor further indicates the promising energy storage nature of the ZnO-incorporated modified g-C3N4 mesoporous nanoarchitecture. Real life application of the ZnO/g-C3N4-derived supercapacitor is illustrated by lighting up a green LED with a series connection of four coin cells.

Graphitic Carbon Nitride Based Semiconductors and Their Applications in the Field of Photocatalysis

An increasing number of advanced semiconductor materials have been reported with the progress of theoretical and practical researches. The graphitic carbon nitride (g-C3N4) stands out as a highly promising semiconductor photocatalyst. It is known for its visible-light reaction and good chemical stability, indicating its potential for extensive use in photocatalysis. Recently, rapid progress has been made in researching g-C3N4-based semiconductor substances in photocatalysis. Till now, a large amount of work has focused on the applications of g-C3N4 in photocatalysis. This work focuses on those researches concerning with g-C3N4-based photocatalytic substances. Their structural characteristics, synthesis techniques, and efficiency enhancement are discussed in detail. Besides, their applications in different photocatalytic reactions are also highlighted. These reactions include hydrogen production by water decomposition, degradation of organic matter, carbon dioxide reduction, and photocatalytic bactericide. This article also points out the problems and challenges in the photocatalytic performance. Meanwhile, the stability of g-C3N4 is also highlighted. It also puts forward the promising research directions of g-C3N4 in the field of photocatalysis.

Graphite Made from Coal by High-Temperature Treatment: An Insight into the Nanometric Carbon Structural Evolution

Graphite made from coal will not only widen the graphite mineral resource, but also significantly improve the value of coal utilization. In this study, anthracite coal was heated in the temperature range of 500 to 2900 °C to study the size increase of nanometric graphite crystallites from anthracite to real graphite. The carbon content rapidly increases to 99.2% when heated from room temperature to 1600 °C, and then gradually increases to 100% when the treated temperature increases to 2900 °C. The FTIR results show that methyl, methylene, and aromatic hydrocarbon, preexisting in the raw anthracite, were preserved in the JZS-500 sample, but that when the treated temperature ≥ 1000 °C, these C-H bonds almost disappear. The basic structural units (nano graphitic carbon) grow into distorted columns, and the basic structural units and micro-columns re-oriented and coalesced to form local molecular oriented domains with the temperature increase from anthracite to JZS-1500. When the temperature ≥ 1600 °C, amorphous carbon, onion-like carbon, turbostratic layers, and graphitic carbon co-occur within the graphitized coals. At the sub-micron scale, carbonization is a homogenous process, whereas graphitization is a heterogenous process. The average graphite crystalline size (La, lateral extension; Lc, stacking height) rapidly increases as the treatment temperature increases from 1600 to 2300 °C. Three coal structural transformation stages were classified according to the nanometric carbon structural evolution with temperature. This study will contribute to the efficient and value-added utilization of coal to make graphite materials.

Green Protocol For Synthesis of Cu2O@g‐C3N4 Photocatalysts For 1, 4 Radical Oxidative Addition of Trans Crotonaldehyde Under Visible Light Condition

AbstractUsing visible light conditions, we have developed a green protocol to prepare copper oxide‐doped graphitic carbon nitride (Cu2O@g‐C3N4) photocatalysts with varied ratios of g‐C3N4 nanosheets to copper oxide‐dopant (0.1 %, 0.5 %, 0.7 %, and 5 % respectively) and characterized through various physicochemical techniques. These photo‐responsive catalysts were used for the 1,4 radical oxidative addition of trans crotonaldehyde into β‐hydroxybutyric acid (BA) as a major product, utilizing 30 % hydrogen peroxide as an oxidant and a white LED (Light Emitting Diode) source. Under the innoculous eco‐friendly stipulations, Cu2O@g‐C3N4 (5 %) exclusively promoted the aforementioned reaction leading to 99.85 % trans crotonaldehyde conversion with 66.57 %, 24.1 %, and 9.1 % selectivity for β‐hydroxybutyric acid, crotonic acid and subsequent radical synthesis, respectively.

Enhanced photocatalytic performance of magnetically reclaimable N-doped g-C3N4/Fe3O4 nanocomposites for efficient tetracycline degradation

The growing environmental challenge posed by the persistence of tetracycline (TC) antibiotics in natural waters is of increasing concern. To address this, there is an imperative need for advanced methods to mitigate TC residues. Herein, we demonstrate the preparation of nitrogen-doped graphitic carbon nitride integrated with magnetic Fe3O4 (N-g-CN/Fe3O4) composites, showcasing narrow band gaps optimized for TC degradation. These advanced materials, conceived through a thermal poly-condensation approach, utilize citric acid and melamine as precursors for nitrogen and g-CN, respectively. These composites exhibit a face-centered cubic architecture, with particle dimensions between 8 to 12 nm and encompassing both meso and microporous structure. The results of the Brunauer–Emmett–Teller analysis indicated specific surface areas of 6.73 m²/g for g-CN, 69.80 m²/g for N-g-CN, 62.55 m²/g for Fe3O4, and 148.32 m²/g for N-g-CN/Fe3O4. These values demonstrate an increase in surface area upon the incorporation of heteroatom of nitrogen and Fe3O4, into the g-CN matrix, thus influence the photocatalytic performance. Under solar light exposure, the synthesized photocatalysts demonstrated photocatalytic activity with a degradation efficiency of 94.16 % within 120 min. Specifically, the N-g-CN/Fe3O4 (22.5 %) composites exhibited remarkable photocatalytic efficiency due to the narrow band gap energy between N-g-CN and Fe3O4, enhanced light absorption in the visible range, and effective charge carrier separation and transportation to the pollutants. N-g-CN/Fe3O4 (22.5 %) composites demonstrated good recyclability (five cycles), magnetic sustainability, and stability for the degradation of TC and emerging pollutants from wastewater using photocatalysts. Similarly, FGCN composites exhibited good recyclability (five cycles), magnetic retrievability, and stability for degrading organic and emerging pollutants from wastewater through photocatalysis. This efficiency can be attributed to the harmonious combination of nitrogen doping, refined surface area, and the natural heterojunction between N-g-CN and Fe3O4.