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3D reticulated carbon nitride materials high-uniformly capture 0D black phosphorus as 3D/0D composites for stable and efficient photocatalytic hydrogen evolution
摘要： Black phosphorus has recently emerged as an excellent 2D semiconductor with high charge-carrier mobility and wide tunable bandgap for photocatalysis. In the research, a simple method was developed to manufacture reticulated carbon nitride materials (CN-4N). Utilizing the self-capturing property of CN-4N to catch the black phosphorus quantum dots (BQ) that were uniformly dispersed in aqueous solution, the BQ were successfully implanted into the interior surface of CN-4N, to form a unique structure instead of the normal exterior surface contact pattern. The optimized CN-4N(BQ) showed good stability and achieved an excellent hydrogen production rate of 13.83 mmol h?1 g?1, which was is 3.3 and 35.5 folds larger than that of CN-4N and bulk CN (NCN), respectively. The experimental results illustrated that greatly improved photocatalytic performance of CN-4N(BQ) was attributed to the joint actions of the abundant active sites provided by ultra-porous structures, the excellent vis-NIR absorption capability, the spatially separated reactive sites for the redox reaction, and the greatly enhanced photoinduced electron-hole separation efficiency. This research provides a novel insight for the rational fabrication of CN-based hybrids for various applications.
关键词： Black phosphorus,carbon nitride,photocatalysis,quantum dots,hydrogen evolution
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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Carbon nanosheet facilitated charge separation and transfer between molybdenum carbide and graphitic carbon nitride toward efficient photocatalytic H2 production
摘要： Interfacial manipulation of nanostructured heterojunction photocatalysts to enhance charge separation and transfer is highly desirable to achieve a high photocatalytic activity. In this work, a well-designed non-noble-metal Mo2C@C/g-C3N4 heterostructure is constructed, in which the intercalated carbon nanosheets serve as a binder to form an excellent interfacial contact between Mo2C and g-C3N4. In addition, large quantities of carbon quantum dotsare found to be homogeneously embedded in the carbon nanosheets. The as-obtained Mo2C@C/g-C3N4 hybrid exhibits a remarkably improved photocatalytic H2 evolution rate of 52.1 μmol h?1 under visible-light irradiation (λ ≥ 420 nm) without co-catalyst, which is up to nearly 260 times higher than that of pristine g-C3N4 (0.2 μmol h?1) under the same conditions. The significant increase in photocatalytic activity mainly results from the fast charge migration and separation between Mo2C and g-C3N4 facilitated by the conducting carbon nanosheets as an efficient electron mediator. Moreover, the carbon quantum dots embedded in the carbon support also promotes solar energy utilization. This work highlights a feasible strategy to explore highly efficient photocatalysts via interfacial engineering on heterojunction composites.
关键词： H2 evolution,Photocatalysis,Water splitting,Carbon nitride,Heterojunction
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
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Carbon Nitride Dots: A Selective Bioimaging Nanomaterial
摘要： In contrast to the recent immense attention in carbon nitride quantum dots (CNQDs) as a heteroatom-doped carbon quantum dot (CQD), their biomedical applications have not thoroughly investigated. The targeted cancer therapy is a prominently researched area in biomedical field. Here, the ability of CNQDs as a selective bioimaging nanomaterial was investigated to assist the targeted cancer therapy. CNQDs were first synthesized using four different precursor sets, involving urea derivatives and the characteristics were compared to select the best candid material for bioapplications. Characterization techniques such as UV-vis, luminescence X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy and transmission electron microscopy were used. These CNQDs were analyzed in in vitro studies of bioimaging and labeling using pediatric glioma cells (SJGBM2) for possible selective biolabeling and nano-distribution inside the cell membrane. The in vitro cellular studies were conducted under long-wavelength emission without the interference of blue autofluorescence. Thus, excitation-dependent emission of CNQDs was proved to be advantageous. Importantly, CNQDs selectively entered SJGBM2 tumor cells while it did not disperse in to normal human embryonic kidney cells (HEK293). The distribution studies in the cell cytoplasm indicated that CNQDs disperse into lysosomes within approximately 6 h after the incubation. The CNQDs exhibited great potential as a possible nanomaterial in selective bioimaging and drug-delivery for targeted cancer therapy.
关键词： Pediatric glioma cells,Long-wavelength emission,Urea derivatives,Carbon nitride Quantum dots,Fluorescence,Selective bioimaging
更新于2025-09-04 15:30:14
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Dual?Wavelength Ratiometric Electrochemiluminescence Immunosensor for Cardiac Troponin I Detection
摘要： Ratiometric electrochemiluminescence (ECL) has attracted special focus in biological analysis field because it could eliminate the environmental interference to gain precise measurement. Herein, a dual?wavelength ratiometric ECL biosensor was designed for detection of cardiac troponin I (cTnI), where (4,4’?dicarboxylicacid?2,2’?bipyridyl) ruthenium(II) (Ru(dcbpy)3 2+) and Au nanoparticles loaded graphene oxide/polyethyleneimine (GPRu?Au) nanomaterial acts as an acceptor, and Au nanoparticles modified graphitic phase carbon nitride nanosheets composite (Au?CNN) acts as donor. Au?CNN shows high and steady ECL signal centered at 455 nm, which is well matched with the adsorption of GPRu?Au, thereby a high efficient electrochemiluminescent resonance energy transfer (ECL?RET) sensing platform is designed. AuNPs facilitate the immobilization of antibody on the nanomaterials through Au?N bond. The high surface area of graphene oxide/polyethyleneimine allows a large number of Ru(dcbpy)3 2+ to be loaded, which immensely amplify the ECL signal. This sensing platform exhibits outstanding analytical performance toward cTnI with a detection limit of 3.94 fg/mL (S/N=3). The high reliability, selectivity and sensitivity of this ratiometric ECL biosensor provides a versatile sensing platform for the bioanalysis.
关键词： carbon nitride nanosheets,ECL biosensor,graphene oxide,Ratiometric electrochemiluminescence,cardiac troponin I,Au nanoparticles
更新于2025-09-04 15:30:14