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Facile two-step synthesis of porous carbon nitride with enhanced photocatalytic activity using a soft template
摘要： In this study, we successfully synthesized a thin-slice layer of graphitic carbon nitride (g-C3N4) with abundant irregular holes by a facile two-step way using Pluronic P123 as a template (CN-P123-x, where x represents the mass ratio of melamine to Pluronic P123). The characterization data suggest that the introduction and removal of Pluronic P123 altered the chemical material structure of the carbon nitride. The CN-P123-x presented lamellar structure with irregular holes, whereas H-g-C3N4 (g-C3N4 prepared using a mild hydrothermal and calcination method without Pluronic P123 or HCl) has a dense blocky structure. Additionally, the prepared CN-P123-x exhibited an effective Rhodamine B (RhB) degradation rate of 98.7% within 40 min of illumination. The optimal photocatalytic activity of CN-P123-6 for degrading RhB was 13.9 times greater than that of H-g-C3N4 in terms of the kinetic constant. Furthermore, the H2 evolution rate of CN-P123-6 can reach 1074.9 μmol?g?1?h?1, whereas that of H-g-C3N4 is only 3.1 μmol?g?1?h?1. It is worth noting that the adoption of HCl (H-g-C3N4-HCl) and Pluronic P123 (CN-P123-6 without HCl) alone has no insignificant effect on photocatalytic performance. The intensive activities are on account of the irregular pores in the thin slice, which increase the specific surface area of the sample and provide additional active sites for reaction. This work provides an excellent basis for improving the performance of the photocatalytic degradation and hydrogen production of carbon nitride.
关键词： Rhodamine B (RhB),H-g-C3N4,hydrogen production,photocatalytic degradation,CN-P123-x
更新于2025-09-23 15:22:29
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One-pot biosynthesis of SnO2 quantum dots mediated by Clitoria ternatea flower extract for photocatalytic degradation of rhodamine B
摘要： In this study, SnO2 quantum dots (QDs) have been successfully biosynthesized using Aparajitha (Clitoria ternatea) flower extract as the green reducing agent and then used as effective photocatalysts for the degradation of rhodamine B (RhB) under UV light irradiation. Clitoria ternatea flower extract contains flavanols and flavonoids, which can serve as reducing agents to convert Sn2+ precursors into Sn° NPs, which are then oxidized to 4–10 nm SnO2 QDs at 400 °C for 2 h. A blue shift in the adsorption wavelength of biosynthesized SnO2 QDs (3.66 eV) in comparison with bulk SnO2 (3.54 eV) is obtained, which can reduce the electron–hole recombination rate of SnO2. In addition, the specific surface area of SnO2 QDs is almost two times higher than that of bulk SnO2, resulting in the acceleration of photocatalytic degradation efficiency and rate of RhB under UVB light irradiation. The photodegradation performance of RhB over SnO2 QDs is highly dependent on several parameters, including H2O2 concentration, catalyst dosage, and pH. The liquid chromatography-mass spectrometric spectra and radical scavenger experiments indicate that the hydroxyl radicals play a crucial role in photodegradation, which can undergo N-deethylation and ring cleavage reactions to produce intermediates of N, N-diethyl-N’-ethylrhodamines, dihydroxybenzoic acid, and maleic acid. Moreover, a possible reaction mechanism for RhB photodegradation over SnO2 QDs is proposed. Results obtained in this study clearly indicate that the extract is an effective bioreagent to develop the green chemistry for the one-pot synthesis of SnO2 QDs photocatalysts for the degradation of pollutants in aqueous solutions.
关键词： Rhodamine B (RhB),Clitoria ternatea flower extract,SnO2 quantum dots,Photocatalytic activity
更新于2025-09-23 15:19:57
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Equilibrium and kinetic modelling of adsorption of Rhodamine B on MoS2
摘要： The recent emergence of layered MoS2, which is an earth-abundant material, has gained increasing attention in various fields. In this work, MoS2 is fabricated via a simple hydrothermal method with different sulfur precursors. The effect of S source on the morphologies and adsorption capacities of Rhodamine B (RhB) onto MoS2 were investigated. The results indicated that the MoS2 prepared by CH4N2S exhibited the highest adsorption capacity. The N2 sorption isotherm indicated that the as-prepared MoS2-CH4N2S is a mesoporous microsphere. In addition, the adsorption process can be well described by the Langmuir isotherm model and the pseudo second-order model. The intra-particle diffusion model was also employed to analyze the adsorption mechanisms, which demonstrated that the intra-particle diffusion within the mesopores played an important role in the overall adsorption process. Based on these results, MoS2-CH4N2S obtained in this work can be served as a promising candidate for dye removal in wastewater.
关键词： adsorption kinetics,dye adsorption,adsorption mechanisms,Rhodamine B (RhB),MoS2
更新于2025-09-10 09:29:36