Efficient degradation of tetracycline via peroxymonosulfate activation by phosphorus-doped biochar loaded with cobalt nanoparticles.

The accumulation of tetracycline hydrochloride (TCH) threatens human health because of its potential biological toxicity. Carbon -based materials with easy isolation and excellent performance that can activate peroxymonosulfate (PMS) to generate reactive oxygen species for TCH degradation are essential, but the development of such materials remains a significant challenge. In this study, based on the idea of treating waste, tricobalt tetraoxide loaded P-doped biochar (Co NP-PBC) was synthesised to activate PMS for the degradation of TCH. Possible degradation pathways and intermediate products of TCH were identified using High performance liquid chromatography tandem mass spectrometry (HPLC-MS) detection and density functional theory analysis. Toxicity analysis software was used to predict the toxicity of the intermediate products. Compared to catalysts loaded with Fe and Mn and other Co-based catalysts, Co NP-PBC exhibited an optimal performance (with a kinetic constant of 0.157 min-1 for TCH degradation), and over 99.0% of TCH can be degraded within 20 min. This mechanism demonstrates that the non-free radical oxidation of 1O2 plays a major role in the degradation of TCH. This study provides insights into the purification of wastewater using BC-based catalysts.

The facile preparation of solid-state fluorescent carbon dots with a high fluorescence quantum yield and their application in rapid latent fingerprint detection.

Because of direct π-π interactions and excessive energy resonance transfer, it is very challenging to prepare carbon dots (CDs) with a high fluorescence quantum yield (QY) in the solid state. In this study, novel CDs which gave solid-state fluorescence (SSF) with high brightness were successfully prepared via a simple microwave-assisted method. The prepared ScCDs can emit strong blue fluorescence in the solid state, and the absolute QY of this ScCDs powder reaches 51.7%. Such a high QY means that the ScCDs powder could be successfully applied in rapid latent fingerprint (LFP) detection. The LFP detection performance of this ScCDs powder was studied in detail, and the results show that the LFPs developed using the ScCDs powder can be visualized with high definition and contrast under different conditions. This research not only developed a new type of SSF-emitting CDs, but it also proved that the developed CDs have great potential for applications in LFP detection, and this research may also provide inspiration and ideas for the design of new SSF-emitting CDs.

Novel yellow solid-state fluorescent-emitting carbon dots with high quantum yield for white light-emitting diodes.

Fluorescence quenching of carbon dots (CDs) occurs in their aggregated state ascribed to direct π-π interactions or excessive resonance energy transfer (RET). Thus, CDs have been severely restricted for applications requiring phosphors that emit in the solid state, such as the fabrication of white light-emitting diodes (WLEDs). In this report, novel CDs with bright solid-state fluorescence (SSF) were synthesized by simple microwave-assisted synthesis method, using 1,4,7,10-tetraazacyclododecane (cyclen) and citric acid as precursors. Under 365 nm UV light, these CDs emit bright yellow SSF, indicating they successfully overcome the aggregation-induced fluorescence quenching (ACQ) effect. When the excitation wavelength (λex) is fixed at 450 nm, the emission peak of the CDs is centered at 546 nm with the Commission Internationale de l'Eclairage chromaticity (CIE) coordinates of (0.43, 0.55), which means that they can be combined with a blue-emitting chip in order to fabricate WLEDs. More importantly, the absolute quantum yield (QY) of these CDs powder reached 48% at λex of 450 nm, which was much higher than many previously reported SSF-emitting CDs and indicating their high light conversion ability in solid-state. Thanks to the excellent optical property of these CDs powder, they were successfully used in the preparation of high-performance WLEDs. This study not only enriches SSF-emitting CD-based nanomaterials with good prospects for application, but also provides valuable reference for subsequent research on the synthesis of solid-state fluorescent CDs.