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Defect engineered mesoporous 2D graphitic carbon nitride nanosheet photocatalyst for Rhodamine B degradation under LED light illumination
摘要： In this work, a nitrogen vacancy induced 2D mesoporous graphitic carbon nitrogen (g-C3N4) nanosheet photocatalyst was successfully synthesized through a simple two step thermal treatment method. The morphology of the nanosheet photocatalyst and the presence of nitrogen vacancy was explored through a wide range of characterization techniques. The as prepared photocatalyst possess an improved visible light absorption efficiency as confirmed from the UV-Visible diffuse reflectance spectroscopy (DRS). Moreover, the improved charge carrier separation efficiency of the nitrogen vacant material was demonstrated from the photoluminescence spectrum. Most importantly, the photocatalyst exhibited an excellent photodegradation efficiency towards rhodamine B (RhB) dye under the illumination of an 18 W LED light. The vacancy induced nanosheets demonstrated a degradation co-efficient of 0.074 min-1 in RhB degradation, which is 9.25 fold higher than that of the bulk g-C3N4. The nanosheets further exhibited an enhanced degradation efficiency toward tetracycline antibiotic. Furthermore, the photocatalyst displayed an outstanding stability even after 5 cycles. A plausible photocatalytic mechanism has also been explained based on the results obtained from the radical scavenging experiments. This study would provide insight into the defect induction mechanism into the 2D g-C3N4 nanosheet and expected to help in rationally designing vacancy induced materials with cost effective application in various environmental fields.
关键词： nitrogen vacancy,LED light irradiation,rhodamine B,mesoporous,2D g-C3N4 nanosheet
更新于2025-09-23 15:21:01
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Three dimensional Pt island-on-Au architectures coupled with graphite carbon nitride nanosheets for effective photo-accelerated methanol electro-oxidation
摘要： Two dimensional (2D) visible-light-activated graphite carbon nitride (CN) nanosheets were used to deposit the traditional electrocatalyst of Pt and Au through a facile one-pot hydrothermal approach. By adjusting different amount of Pt and Au, 3D Pt island-on-Au architectures were formed on the surface of CN nanosheets (Pt-Au/CN). The obtained Pt-Au/CN composite was used for electrocatalytic methanol oxidation reaction (MOR). Comparing with Pt/CN modified electrode, Pt-Au/CN exhibited 13.8 times enhancement on the electrocatalytic activity of MOR. Interestingly, when Pt-Au/CN composite was illuminated with visible light, the current density and stability were continuously enhanced by evaluating of cyclic voltammetry (CV), chronopoenttiometric (CP), chronoamperometry (CA), and electrochemical impedance spectra (EIS). The bimetallic electronic effects of Pt and Au; 3D Pt islands-on-Au architectures; 2D support nanosheet of CN, and the synergistic effect of photo- and electro-catalytic processes resulted in the improved electrocatalytic activity and stability. The present investigations provide a promising future to construct highly efficient electrocatalyst by combining bimetal on semiconductor support and with the assistance of visible light irradiation.
关键词： visible light,g-C3N4 nanosheet,methanol oxidation,photo-accelerated electrocatlysis,Pt island-on-Au architectures
更新于2025-09-12 10:27:22
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Improved fluorescence test of chromium (VI) in aqueous solution with g-C3N4 nanosheet and mechanisms
摘要： g-C3N4 nanosheet has been modified by secondary calcination at 550 °C and HNO3 treatment for effectively testing Cr(VI) in aqueous solution via the fluorescence decay according to the inner filter effects proved by the nearly-unchanged time-resolved decay process. The improved fluorescence test performance is attributed to the promoted adsorption of Cr(VI) on resulting g-C3N4 by increasing surface area and the surface positive charge sites. The limit of detection (LOD) is 0.3 μM, which is confirmed by the Stern-Volmer equation with the linear range of 1.0–100.0 μM versus the fluorescence intensity on the optimized conditions of pH = 3 and excitation wavelength of 350 nm. Moreover, at the low-concentration range of 0.2–5.0 μM, it is well linear to the fluorescence intensity by the double logarithmic plot, with the LOD of 0.06 μM. This work provides a feasible route to synthesize g-C3N4-based nanomaterials for effectively detecting Cr(VI) in the solution.
关键词： Secondary calcination,g-C3N4 nanosheet,Cr(VI) testing,HNO3 treatment,Fluorescence decay
更新于2025-09-10 09:29:36
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Effective protect of oxygen vacancies in carbon layer coated black TiO2-x/CNNS hetero-junction photocatalyst
摘要： Carbon layer coated black TiO2-x/g-C3N4 nanosheets (C@TiO2-x/CNNS) heterojunction photocatalysts were successfully prepared via a polydopamine dopamine carbonization route for the first time. It was found that the hydrogen evolution rate of C@TiO2-x/CNNS was 417.2 μmol h-1 g-1 under visible light irradiation, which was much higher than that of other prepared photocatalysts in solar water splitting process at the same conditions, and obvious decrease in catalytic activity can be observed after three recycles. The formation of carbon layer on the surface of TiO2-x can effectively protect Ti3+ and oxygen vacancies (Ovs) from oxidation by air and dissolved O2, afterwards much more Ti3+/Ovs are exsited, which can serve as charge carrier traps to inhibit the recombination of light-excited electrons-holes. Therefore, C@TiO2-x/CNNS showed a highly conductivity, rapidly effective electron-hole separation and lower transmission resistance comprehensive consideration of the advantages of carbon layer and hetero-junction, which are of great benefit to the improvement of photocatalytic performance. Hence, a new catalytic tactic namely layer-protection effect was founded and this strategy for boosting hydrogen evolution and protection Ti3+/Ovs may give us some hints on the design of photocatalytic systems.
关键词： black TiO2,visible light H2 evolution,g-C3N4 nanosheet,carbon layer protect oxygen vacancy
更新于2025-09-10 09:29:36