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Visible-light-responsive Photocatalyst of Graphitic Carbon Nitride for Pathogenic Biofilm Control
摘要： Pathogenic biofilms raise significant health and economic concerns, because these bacteria are persistent and can lead to long-term infections in vivo and surface contamination in healthcare and industrial facilities or devices. Compared with conventional antimicrobial strategies, photocatalysis holds promise for biofilm control because of its broad-spectrum effectiveness under ambient conditions, low cost, easy operation, and reduced maintenance. In this study, we investigated the performance and mechanism of Staphylococcus epidermidis biofilm control and eradication on the surface of an innovative photocatalyst, graphitic carbon nitride (g-C3N4), under visible light irradiation, which overcame the need for ultraviolet (UV) light for many current photocatalysts (e.g., titanium dioxide (TiO2)). Optical coherence tomography (OCT) and confocal laser scanning microscopy (CLSM) suggested that g-C3N4 coupons inhibited biofilm development and eradicated mature biofilms under the irradiation of white light-emitting diodes (LEDs). Biofilm inactivation was observed occurring from the surface towards the center of the biofilms, suggesting that the diffusion of reactive species into the biofilms played a key role. By taking advantage of scanning electron microscopy (SEM), CLSM, and atomic force microscopy (AFM) for biofilm morphology, composition, and mechanical property characterization, we demonstrated that photocatalysis destroyed the integrated and cohesive structure of biofilms and facilitated biofilm eradication by removing the extracellular polymeric substances (EPS). Moreover, reactive oxygen species (ROS) generated during g-C3N4 photocatalysis were quantified via reactions with radical probes, and 1O2 was believed to be responsible for biofilm control and removal. Our work highlights the promise of using g-C3N4 for a broad range of antimicrobial applications, especially for the eradication of persistent biofilms under visible light irradiation, including photodynamic therapy, environmental remediation, food industry applications, and self-cleaning surface development.
关键词： graphitic carbon nitride,mechanical properties,extracellular polymeric substances,biofilms,visible light
更新于2025-09-09 09:28:46
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Fabrication of Perylene Tetracarboxylic Diimide-Graphitic Carbon Nitride Heterojunction Photocatalyst for Efficient Degradation of Aqueous Organic Pollutants
摘要： Metal-free g-C3N4 is the promising candidate for the next generation visible light-responsive photocatalyst, however, high recombination probability of the photogenerated charge carriers on g-C3N4 limits its photocatalytic activity. To further increase the intrinsic photocatalytic activity of g-C3N4, here perylene tetracarboxylic diimide-g-C3N4 heterojunctions (PDI/GCN) are prepared by one-step imidization reaction between perylene tetracarboxylic dianhydride (PTCDA) and g-C3N4 in aqueous solution. By the combination of various testing results it is confirmed that the surface hybridization of PTCDA and g-C3N4 in the PDI/GCN heterojunctions via O=C?N?C=O covalent bonds occurs at lower PTCDA-to-g-C3N4 weight percentage. By selecting p-nitrophenol and levofloxacin as the target organic pollutants, the visible light photocatalytic performance of the PDI/GCN heterojunctions are studied. It shows that the PDI/GCN heterojunction prepared at PTCDA-to-g-C3N4 weight percentage of 1% exhibits remarkably higher visible light photocatalytic degradation and mineralization ability towards aqueous target pollutants as compared with g-C3N4 and Degussa P25 TiO2. On the basis of the experimental results including photoelectrochemistry, indirect chemical probe and electron spin resonance spectroscopy it is verified that the surface hybridization in the heterojunctions is responsible for this enhanced photocatalytic activity via accelerating the migration and separation of the photogenerated charge carriers, causing to produce more active species like ?O2?, hVB+ and ?OH for deep oxidation of PNP or LEV to CO2 and inorganic anions.
关键词： graphitic carbon nitride,heterojunction,perylene tetracarboxylic diimide,visible light photocatalysis,organic pollutant
更新于2025-09-04 15:30:14
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Ultrathin Carbon Nitride with Atomic-Level Intra-Plane Implantation of Graphited Carbon Ring Domain for Superior Photocatalytic Activity in Visible/Near-Infrared Region
摘要： Efficient photocarrier transfer and sufficient light absorption play a crucial role in improving photocatalytic H2 evolution activity. Hence, we report a conceptual design of ultrathin carbon nitride intra-plane implanted with graphited carbon ring domain (CN-GP) via thermal polymerization of polyvinyl butyral and melamine membrane, displaying obvious disparities in the decoration type compared with the adsorption of graphene on the bulk g-C3N4 surface. This unique intra-plane heterostructural CN-GP can greatly sheathe the visible/near-infrared light range, expedite electron-hole pair separation and weaken the barrier of the photocarrier transfer through their suitable energy band structures and in-built electric felds. Consequently, the CN-GP displayed remarkable photocatalytic activity under visible/near-infrared illumination by acquiring a H2 production rate of 11.33 mmol g-1 h-1, and even showed near-infrared-drived photocatalytic activity. This work presents an effective way for the rational fabrication of g-C3N4-based materials for broad-spectrum-driven photocatalysis.
关键词： Intra-plane implantation,Hydrogen production,Vis-NIR,Graphitic carbon nitride,Inter-plane decoration
更新于2025-09-04 15:30:14
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Semiconductor Heterojunctions for Enhanced Visible Light Photocatalytic H2 Production
摘要： Semiconductor-based heterojunctions have been shown to be effective photocatalytic materials to overcome the drawbacks of low photocatalytic efficiency that results from a high rate of electron?hole recombination and narrow photo-response range. In this paper, we report on the study of heterojunctions made from visible light active, graphitic carbon nitride, g-C3N4), and UV light active, strontium pyroniobate, Sr2Nb2O7. Heterojunctions made from a combination of g-C3N4 and nitrogen-doped Sr2Nb2O7 obtained at different temperatures were also studied to determine the effect of N doping. The photocatalytic performance was evaluated by using photocatalytic hydrogen evolution reaction (HER)from water g under visible light irradiation. It was found that the photocatalytic activities of as prepared heterojunctions are significantly higher than that of individual components under similar conditions. Heterojunction formed from g-C3N4 and N-doped Sr2Nb2O7 at 700oC (CN/SNON-700) showed better performance than heterojunction made from g-C3N4 and Sr2Nb2O7 (CN/SNO). A plausible mechanism for the heterojunction enhanced photocatalytic activity is proposed based on, relative band positions, and photoluminescence data.
关键词： graphitic carbon nitride,visible light photocatalysis,strontium pyroniobate,Semiconductor heterojunctions,hydrogen production
更新于2025-09-04 15:30:14
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Tuning Nitrogen Content in Graphitic Carbon Nitride by Isonicotinic acid for Highly Efficient Photocatalytic Hydrogen Evolution
摘要： Graphitic carbon nitride (CN) with various nitrogen contents can be prepared to regulate its electronic structure and energy band levels. The newly-prepared graphitic carbon nitride manifests high photocatalytic activity. In this work, nitrogen-rich CN (CN-NR100) and nitrogen-deficient CN (CN-ND500) were prepared by tuning nitrogen contents in CN while using isonicotinic acid (IA) as an additive in the precursors. It is found that IA reacting with urea can introduce its nitrogen to CN, while reacting with CN can take away the amino group of CN, thus reduces its nitrogen content. Interestingly, the gas that comes from the decomposition of IA is essential for the formation of porous morphology in CN. Both CN-NR100 and CN-ND500 can provide more photocatalytic sites, narrow bandgaps to enhance the absorption of visible light and significantly improve the charge carrier separation efficiency. Therefore, CN-NR100 and CN-ND500 manifest an excellent photocatalytic hydrogen evolution rate of 73 μmol h-1 (about 4 times of that of CN) and 120 μmol h-1 (6.7 times of that of CN), respectively. This work provides an efficient strategy to prepare CN with different nitrogen contents by pyrolysis of precursors modified by IA for high photocatalytic hydrogen evolution.
关键词： Graphitic carbon nitride,Nitrogen content,Isonicotinic acid,Hydrogen evolution
更新于2025-09-04 15:30:14
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One pot synthesis of bismuth oxide/graphitic carbon nitride composites with high photocatalytic activity
摘要： A one pot synthesis of heterostructured bismuth oxide (Bi2O3)/graphitic carbon nitride (g-CN) photocatalysts was developed using Bi(NO3)3 and melamine in 1 M HNO3 as precursors. SEM, TEM and XPS analyses demonstrate that Bi2O3 is closely associated to g-CN, producing contacted interfaces between the two materials. The loading in Bi2O3 was varied from 1.25 to 10 wt% and the highest photocatalytic activity was obtained for the composite containing 2.5% BBN. The Bi2O3 (2.5%)/g-CN material exhibits excellent photocatalytic activity under visible light irradiation for the degradation of RhB as well as a good stability and reusability. Reactive species trapping experiments demonstrated that superoxide O2? radicals and to a lesser extent holes play a key role in the decomposition of the dye. The high photocatalytic activity of the Bi2O3 (2.5%)/g-CN composite originates from the effective separation of photogenerated charge carriers, which was confirmed by photoluminescence and photocurrent measurements, and from its high specific surface area (26.1 m2/g). The convenient and low cost method developed for the preparation of g-CN-based photocatalysts is of high interest for the synthesis of new heterostructured materials for environmental remediation.
关键词： Graphitic carbon nitride,Heterostructured photocatalyst,Bismuth oxide
更新于2025-09-04 15:30:14