Search Results (57)

At present, various carbon materials are available as supports for metal-containing catalytic species. Carbon-based materials find application in many industrial heterogeneous catalytic processes, such as selective hydrogenation, oxidation, cross-coupling, etc. The simplicity of preparation, low cost, high stability, and the possibility of tuning surface composition and porosity cause the widespread use of metal catalysts supported on carbon materials. The surface chemistry of carbon supports plays a crucial role in catalysis, since it allows for control over the sizes of metal particles and their electronic properties. Moreover, metal-free functionalized carbonaceous materials themselves can act as catalysts. In this review, we discuss the recent progress in the field of the application of carbon supports in catalysis by metals, with a focus on the role of carbon surface functionalities and metal-support interactions in catalytic processes used in fine organic synthesis. Among carbon materials, functionalized/doped (O, N, S, P, B) activated carbons, graphenes, carbon nanotubes, graphitic carbon nitride, and carbonizates of polymers are considered supports for mono- and bimetallic nanoparticles. Full article

Developing efficient photocatalysts is essential for sustainable wastewater treatment and tackling global water pollution. Graphitic carbon nitride (g-C₃N₄) is a promising material because it is active under visible light and chemically stable. However, its practical application is limited by fast recombination of charge carriers and a low surface area. In this study, we report a simple hydrothermal method to synthesize exfoliated porous g-C₃N₄ (E-PGCN) combined with Ti₃C₂ MXene to form a heterojunction composite that addresses these issues. Various characterization techniques (FTIR, XRD, XPS, SEM, BET) confirmed that adding MXene improves light absorption, increases surface area (53.7 m²/g for the composite versus 21.4 m²/g for bulk g-C₃N₄ (BGCN)), and enhances charge separation at the interface. Under UV-visible light irradiation with Rhodamine B (RhB) as the model pollutant, the E-PGCN/Ti₃C₂ MXene composite containing 3 wt% MXene demonstrated an impressive degradation efficiency of 93.2%. This performance is superior to BGCN (66.6%), E-PGCN (82.5%), and E-PGCN/Ti₃C₂ MXene-5 wt% composites (81%). This is due to the excess Mxene which caused agglomeration and reduced activity. Scavenger studies identified electron radicals as the dominant reactive species, with optimal activity at pH ~4.5. This enhanced performance, 1.4 times greater than BGCN and 1.13 times higher than E-PGCN, is ascribed to the synergistic interplay between the excellent electrical conductivity of MXene and the porous structural features of E-PGCN. This work highlights the importance of morphological engineering and heterojunction design for advancing metal-free photocatalysts, offering a scalable strategy for sustainable water purification. Full article

The green synthesis of hydrogen peroxide (H₂O₂) is crucial for sustainable chemical production, but pristine graphitic carbon nitride (g-C₃N₄) suffers from low H₂O₂ yield owing to limited visible light absorption and swift charge recombination. Herein, a novel metal-free carbon nitride oxide/biochar photocatalytic system (CNO-B) was developed via a simple low-temperature calcination without post-treatment. The synergistic effect of carbonyl functionalization and biochar integration significantly enhanced light harvesting capabilities and charge carrier separation efficiency, achieving an exceptional H₂O₂ production rate of 2483 μmol g⁻¹ h⁻¹ upon irradiation (five times higher compared with pure g-C₃N₄). This work provides valuable insights into minimalist synthesis strategies for designing functional materials and demonstrates a practical approach for valorizing biomass waste in sustainable photocatalytic applications. Full article

Gallic acid (GA), a polyphenol extensively used in the food, wine, and pharmaceutical industries, is known for its inhibitory effects on soil microbial activity. Photocatalytic degradation offers an environmentally friendly solution for GA removal from water. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized by two methods: thermal exfoliation (CN-E) and supramolecular assembly via hydrothermal processing (HCN-II). Structural analyses by XRD, FTIR, and XPS confirmed the formation of the g-C₃N₄ framework, while SEM revealed that CN-E consisted of folded and curled nanosheets, whereas HCN-II displayed a polyhedral–nanosheet hybrid architecture with internal channels. Both materials achieved approximately 80% GA degradation within 180 min under visible-light irradiation, yet HCN-II exhibited a superior apparent rate constant (k = 0.01156 min⁻¹) compared with CN-E. Radical trapping experiments demonstrated that O₂•⁻ and h⁺ were the primary reactive oxygen species involved, with OH• making a minor contribution. The enhanced performance of HCN-II is attributed to its higher surface area, improved light harvesting, and efficient charge separation derived from supramolecular assembly. These findings highlight the potential of engineered g-C₃N₄ nanostructures as efficient, metal-free photocatalysts for the degradation of recalcitrant organic pollutants in water treatment applications. Full article

The metal-free polymeric semiconductor graphitic carbon nitride (g-C₃N₄) has emerged as a promising material for photocatalytic applications due to its responsiveness to visible light, adjustable electronic structure, and stability. This review systematically summarizes recent advances in preparation strategies, including thermal polycondensation, solvothermal synthesis, and template methods. Additionally, it discusses modification approaches such as heterojunction construction, elemental doping, defect engineering, morphology control, and cocatalyst loading. Furthermore, it explores the diverse applications of g-C₃N₄-based materials in photocatalysis, including hydrogen (H₂) evolution, carbon dioxide (CO₂) reduction, pollutant degradation, and the emerging field of piezoelectric photocatalysis. Particular attention is given to g-C₃N₄ composites that are rationally designed to enhance charge separation and light utilization. Additionally, the synergistic mechanism of photo–piezocatalysis is examined, wherein a mechanically induced piezoelectric field facilitates carrier separation and surface reactions. Despite significant advancements, challenges persist, including limited visible-light absorption, scalability issues, and uncertainties in the multi-field coupling mechanisms. The aim of this review is to provide guidelines for future research that may lead to the development of high-performance and energy-efficient catalytic systems in the context of environmental and energy applications. Full article

Graphitic carbon nitride (g-C₃N₄)-based materials hold significant promise for environmental remediation, particularly water purification, owing to their unique electronic structure, metal-free composition, and robust chemical stability. However, powdered g-C₃N₄ faces challenges such as particle aggregation, poor recyclability, and limited exposure of active sites. Structuring g-C₃N₄ into hydrogels or aerogels—three-dimensional porous networks offering high surface area, rapid mass transport, and tunable porosity—represents a transformative solution. This review comprehensively examines recent advances in g-C₃N₄-based gels, covering synthesis strategies such as crosslinking (physical/chemical), in situ polymerization, and the sol–gel and template method. Modification approaches including chemical composition and structural engineering are systematically categorized to elucidate their roles in optimizing catalytic activity, stability, and multifunctionality. Special emphasis is placed on environmental applications, including the removal of emerging contaminants and heavy metal ions, as well as solar-driven interfacial evaporation for desalination. Throughout, the critical interplay between gel structure/composition and performance is evaluated to establish design principles for next-generation materials. Finally, this review identifies current challenges regarding scalable synthesis, long-term stability, in-depth mechanistic understanding, and performance in complex real wastewater matrices. This work aims to provide valuable insights and guidance for advancing g-C₃N₄-based hydrogel and aerogel technologies in environmental applications. Full article

Herein, carbon nanofiber (CNF) was prepared by pyrolyzing electrospun cellulose nanofiber, which was further used to incorporate with graphitic carbon nitride (g-C₃N₄) to prepare metal-free photocatalyst (CNF/g-C₃N₄). CNF/g-C₃N₄ was then used to degrade bisphenol A (BPA) under visible light with the assistance of peroxymonosulfate (PMS). It was illustrated from the results that CNF with conjugated aromatic structure could significantly enhance the light absorption range and capability. At the existence of PMS, 0.5 g/L of CNF/g-C₃N₄ could efficiently degrade 0.05 mM of BPA within 45 min with a high total organic carbon removal rate of >70% under visible light. It was found that the reaction system could generate various reactive oxygen species (ROSs) including hydroxyl radical, superoxide radical and singlet oxygen for BPA degradation. Due to the existence of these species, the reaction system exhibited high performance adaptability towards abundant water matrices and high stability under consecutive runs. This work prospects a new strategy to develop a high-performance advanced oxidation system for quick organic pollutant degradation and mineralization. Full article

The electrochemical reduction of carbon monoxide (COER) offers a promising route for generating value-added multi-carbon (C₂₊) products, such as ethanol, but achieving high catalytic performance remains a significant challenge. Herein, we performed comprehensive density functional theory (DFT) computations to evaluate CO-to-ethanol conversion on single metal atoms anchored on graphitic carbon nitride (TM/g–CN). We showed that these metal atoms stably coordinate with edge N sites of g–CN to form active catalytic centers. Screening 20 TM/g–CN candidates, we identified V/g–CN and Zn/g–CN as optimal catalysts: both exhibit low free-energy barriers (<0.50 eV) for the key ^*CO hydrogenation steps and facilitate C–C coupling via an Eley–Rideal mechanism with a negligible kinetic barrier (~0.10 eV) to yield ethanol at low limiting potentials, which explains their superior COER performance. An analysis of d-band centers, charge transfer, and bonding–antibonding orbital distributions revealed the origin of their activity. This work provides theoretical insights and useful guidelines for designing high-performance single-atom COER catalysts. Full article

Since the publication of the 12 principles of green chemistry in 1998 by Paul Anastas and John Warner, the green synthesis of metal and metal oxide nanoparticles has emerged as an eco-friendly and sustainable alternative to conventional chemical methods. Plant-based synthesis utilizes natural extracts as reducing and stabilizing agents, minimizing harmful chemicals and toxic by-products. Ag nanoparticles (Ag-NPs) exhibit strong antibacterial activity; Au nanoparticles (Au-NPs) are seen as a promising carrier for drug delivery and diagnostics because of their easy functionalization and biocompatibility; and ZnO nanoparticles (ZnO-NPs), on the other hand, produce reactive oxygen species (ROS) that kill microorganisms effectively. These nanoparticles also demonstrate antioxidant properties by scavenging free radicals, reducing oxidative stress, and preventing degenerative diseases. Green syntheses based on plant extracts enhance biocompatibility and therapeutic efficacy, making them suitable for antimicrobial, anticancer, and antioxidant applications. Applying a similar “green synthesis” for advanced nanostructures like graphitic carbon nitride (GCN) is an environmentally friendly alternative to the traditional ways of doing things. GCN exhibits exceptional photocatalytic activity, pollutant degradation efficiency, and electronic properties, with applications in environmental remediation, energy storage, and biomedicine. This review highlights the potential of green-synthesized hybrid nanocomposites combining nanoparticles and GCN as sustainable solutions for biomedical and environmental challenges. The review also highlights the need for the creation of a database using a machine learning process that will enable providing a clear vision of all the progress accomplished till now and identify the most promising plant extracts that should be used for targeted applications. Full article

The rational development of single-atom catalysts (SACs) for selective formic acid dehydrogenation (FAD) requires an atomic-scale understanding of metal–support interactions and electronic modulation. In this study, spin-polarized density functional theory (DFT) calculations were performed to systematically examine platinum-group SACs anchored on graphitic carbon nitride (g-C₃N₄). The findings reveal that Pd and Au SACs exhibit superior selectivity toward the dehydrogenation pathway, lowering the free energy barrier by 1.42 eV and 1.39 eV, respectively, compared to the competing dehydration route. Conversely, Rh SACs demonstrate limited selectivity due to nearly equivalent energy barriers for both reaction pathways. Stability assessments indicate robust metal–support interactions driven by d–p orbital hybridization, while a linear correlation is established between the d-band center position relative to the Fermi level and catalytic selectivity. Additionally, charge transfer (ranging from 0.029 to 0.467 e) substantially modulates the electronic structure of the active sites. These insights define a key electronic descriptor for SAC design and offer a mechanistic framework for optimizing selective hydrogen production. Full article

The persistent threat of heavy metal ions (e.g., Pb²⁺, Hg²⁺, Cd²⁺) in aqueous environments to human health underscores an urgent need for advanced sensing platforms capable of rapid and precise pollutant monitoring. Graphitic carbon nitride (g-C₃N₄), a metal-free polymeric semiconductor, has emerged as a revolutionary material for constructing next-generation environmental sensors due to its exceptional physicochemical properties, including tunable electronic structure, high chemical/thermal stability, large surface area, and unique optical characteristics. This review systematically explores the integration of g-C₃N₄ with functional nanomaterials (e.g., metal nanoparticles, metal oxide nanomaterials, carbonaceous materials, and conduction polymer) to engineer high-performance sensing interfaces for heavy metal detection. The structure-property relationship is critically analyzed, emphasizing how morphology engineering (nanofibers, nanosheets, and mesoporous) and surface functionalization strategies enhance sensitivity and selectivity. Advanced detection mechanisms are elucidated, including electrochemical signal amplification, and photoinduced electron transfer processes enabled by g-C₃N₄’s tailored bandgap and surface active sites. Furthermore, this review addresses challenges in real-world deployment, such as scalable nanomaterial synthesis, matrix interference mitigation, and long-term reliable detection. This work provides valuable insights for advancing g-C₃N₄-based electrochemical sensing technologies toward sustainable environmental monitoring and intelligent pollution control systems. Full article

Vacancy defect graphitic carbon nitride (g-C₃N₄) and conjugated polyimide (PI) polymer photocatalysts have become increasingly recognized as metal-free photocatalysts featuring an appropriate bandgap. The narrow absorption spectrum of visible light and the rapid recombination rate of the photoexcited charge carriers in PI polymers and g-C₃N₄ impede its photocatalytic performance. The presence of oxygen vacancies (OVs) in PI polymer photocatalysts, as well as nitrogen vacancies (NVs) and carbon vacancies (CVs) in g-C₃N₄, can significantly enhance the migration of photogenerated electrons. Adding vacancies to improve the electronic structure and band gap width can greatly enhance the photocatalytic efficiency of PI polymers and g-C₃N₄. Defect engineering is important for increasing the photocatalytic ability of PI-polymer and g-C₃N₄. There remains a notable absence of thorough review papers covering the synthesis, characterization, and applications of vacancy-rich PI-polymer and g-C₃N₄ in photocatalysis. This review paper examines the roles of OVs in PI-polymer, NVs, and CVs in g-C₃N₄ and thoroughly summarizes the preparation approaches employed before and after, as well as during polymerization. This review scrutinizes spectroscopic characterization techniques, such as EPR, XPS, PAS, XRD, FTIR, and NMR, for vacancy defect analysis. We also reviewed the role of vacancies, which include light absorption, photogenerated charge carrier separation, and transfer dynamics. This review could serve as a comprehensive understanding, a vacancy-engineered design framework, and a practical guide for synthesizing and characterizing. Full article

Carbon nitrides are polymeric materials with a broad range of applications, including photocatalysis. Among them, graphitic carbon nitride (g-C₃N₄), a low-cost material, is an excellent photocatalyst under visible light irradiation owing to its features such as correct band positions, high stability and non-toxicity. g-C₃N₄ is a metal-free material that is easily synthesized by polymerizing nitrogen-rich compounds and is an efficient heterogeneous catalyst for many reaction procedures due to its distinctive electronic structure and the benefits of the mesoporous texture. In addition, in situ or post-modification of g-C₃N₄ can further improve catalytic performance or expand its application for remediating environmental pollution. Water pollution from organic compounds such as pesticides and pharmaceuticals is increasing dramatically and is becoming a serious problem around the world. These pollutants enter water supplies in a variety of ways, including industrial and hospital wastewater, agricultural runoff, and chemical use. To solve this problem, photocatalysis is a promising technology. Without the use of other oxidative chemicals, g-C₃N₄ uses renewable solar energy to transform harmful pollutants into harmless products. As a result, much recent research has focused on the photocatalytic activity of g-C₃N₄ for wastewater treatment. For this reason, the main objective of this paper is to contribute a chronological overview of the bibliometrics on g-C₃N₄ for the removal of pesticides and pharmaceuticals from water using the tools BibExcel, Bibliometrix and R-Studio IDE. A bibliometric analysis was performed using the Science Citation Index Expanded (WoS^©) database to analyze the scientific literature published in the field over the last 10 years. The results were used to identify limitations and guide future research. Full article

Graphitic carbon nitride (g-C₃N₄) has gained significant attention due to its unique physicochemical properties as a metal-free, two-dimensional, carbon-based polymeric fluorescent substance composed of tris-triazine-based patterns with a slight hydrogen content and a carbon-to-nitrogen ratio of 3:4. It forms layered structures like graphite and demonstrates exciting and unusual physicochemical properties, making g-C₃N₄ widely used in nanoelectronic devices, spin electronics, energy storage, thermal conductivity materials, and many others. The biomedical industry has greatly benefited from its excellent optical, electrical, and physicochemical characteristics, such as abundance on Earth, affordability, vast surface area, and fast synthesis. Notably, the heptazine phase of g-C₃N₄ displays stable electronic bands. Another significant quality of this semiconductor material is its excellent fluorescence property, which is also helpful in preparing biosensors. Based on g-C₃N₄, electrochemical biosensors have provided better biocompatibility, higher sensitivity, low detection limits, nontoxicity, excellent selectivity, and surface versatility of functionalization for the delicate identification of target analytes. This review covers the latest studies on using efflorescent graphitic carbon nitride to fabricate electrochemical biosensors for various biomarkers. Carbon nitrides have been reported to possess excellent electroactivity properties, a massive surface-to-volume ratio, and hydrogen-bonding functionality, thus allowing electrochemical-based, highly sensitive, and selective detection platforms for an entire array of analytes. Considering the preceding information, this review addresses the fundamentals and background of g-C₃N₄ and its numerous synthesis pathways. Furthermore, the importance of electrochemical sensing of diverse biomarkers is emphasized in this review article. It also discusses the current status of the challenges and future perspectives of graphitic carbon nitride-based electrochemical sensors, which open paths toward their practical application in aspects of clinical diagnostics. Full article

Graphitic phase carbon nitride (g-C₃N₄, abbreviated as CN) can be used as a photocatalyst to reduce the concentration of atmospheric carbon dioxide. However, there is still potential for improvement in the small band gap and carrier migration properties of intrinsic materials. K-B co-doped CN (KBCN) was investigated as a promising photocatalyst for carbon dioxide reduction via the Density Functional Theory (DFT) method. The electronic and optical properties of CN and KBCN indicate that doping K and B can improve the catalytic performance of CN by promoting charge migration and separation. In terms of the Gibbs free energy change, the CO₂ reduction reaction catalysed by KBCN results in CH₃OH, and its optimal pathway is CO₂ → *CO₂ → *COOH → CO → *OCH → HCHO → *OCH₃ → CH₃OH. Compared with CN, the doping elements K and B shift the rate-determining step from CO₂ → *CO₂ to *CO₂ → *COOH. The K and B elements co-doping tuned the charge distribution between the catalyst and the adsorbate and reduced the Gibbs free energy of the rate-determining step from 1.571 to 0.861 eV, suggesting that the CO₂ reduction activity of KBCN is superior to that of CN. Our work provides useful insights for the design of metallic–nonmetallic co-doped CN for photocatalytic CO₂ reduction (CO₂PR) reactions. Full article