- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Self-assembled BiOCl/Ti3C2T composites with efficient photo-induced charge separation activity for photocatalytic degradation of p-nitrophenol
摘要： Cocatalysts play an important role in increasing the photogenerated electron-hole separation rate of catalytic materials. Here, we selected a novel 2D material Ti3C2Tx (Tx = –OH, –O) as a cocatalyst and synthesized BiOCl/Ti3C2Tx (named as BT-n n = 0, 0.5, 1.0, 2.0, 4.0) composite materials by electrostatic self-assembly. We carefully characterized the structure, morphology and photoelectric performance of the composites, finding that we successfully synthesized 2D/2D BiOCl/Ti3C2Tx materials. The photocatalytic performance of the composites was evaluated by degradation of p-nitrophenol as a pollutant under simulated illumination. Among the composites obtained, BT-2.0 showed the best photocatalytic performance; specifically, its removal rate reached 97.86% and its degradation rate was about 3.3 times that of BT-0. Free radicals in the photocatalytic process were tested by electron paramagnetic resonance, which showed that superoxide radicals and holes are the most active free radicals in the system due to the higher photogenerated electron separation efficiency of BT-2.0. Therefore, constructing a heterojunction with Ti3C2Tx as a cocatalyst can improve the photocatalytic activity of BiOCl, which may provide new insights into the selection of novel co-catalytic materials in the field of photocatalysis.
关键词： p-nitrophenol,photocatalytic degradation,MXene,superoxide radicals,BiOCl
更新于2025-09-23 15:21:01
-
Oxygen Stabilizes Photoluminescence of CdSe/CdS Core/Shell Quantum Dots via Deionization
摘要： By taking advantage of well-defined spectroscopic signatures of high-quality CdSe/CdS core/shell QDs, effects of oxygen on photoluminescence (PL) of QDs were studied systematically and quantitatively at both single-dot and ensemble (on substrate and in solution) levels, which reveals a unified yet simple picture. With a sufficient amount of oxygen in the system during photo-excitation, the core/shell QDs in all forms would be deionized timely from the photo-generated and inefficient trion state back to efficient single-exciton state, with superoxide radicals as the reduction product of oxygen. Under a given excitation power, rates of both spontaneous deionization and photo-deionization channels increased by increasing the oxygen pressure, but photo-ionization of the QDs was barely affected by the oxygen pressure. While stabilizing PL by oxygen was identified for both CdSe plain core and CdSe/CdS core/shell QDs, irreversible photo-corrosion was only observed for CdSe plain core QDs, suggesting importance of high-quality epitaxial shells for QDs in various applications.
关键词： CdSe/CdS,superoxide radicals,oxygen,deionization,photoluminescence,quantum dots
更新于2025-09-19 17:13:59
-
Photocatalytic activation of peroxymonosulfate by surface-tailored carbon quantum dots
摘要： In this study, carbon quantum dots (CQDs) were synthesized by a low-cost and scalable approach and the oxygen functional groups were fine-tuned by chemical post-treatment. It was found that the CQDs could be applied as visible-light-responsive photocatalysts for activation of peroxymonosulfate (PMS) and remediation of aqueous organic dyes. Phenylhydrazine modified CQDs (CQDs-PH) presented high efficiency for degradation of methylene blue due to selective removal of carboxylic groups and inhibited recombination of photogenerated electron-hole pairs. The effects of catalyst dosage, species and concentrations of dyes, and initial pH values on the photodegradation efficiency were systematically investigated and the alkaline condition facilitates the separation of photoinduced charge carriers and promotes the dye decoloration. The reactive oxygen species produced in the photocatalysis were identified by radical quenching tests and the mechanism was elucidated. Superoxide radicals were generated from PMS activation via electron transfer from CQDs and played the primary role for organic oxidation. In addition, photogenerated holes on the valence band of CQDs also participated in the dye decomposition.
关键词： peroxymonosulfate,superoxide radicals,Photocatalysis,oxygen groups,carbon quantum dots (CQDs)
更新于2025-09-19 17:13:59