In the present study, carbon-dots (CDs) were derived from the thermal oxidation of an agricultural waste, bitter tea residue, to obtain different sp/sp ratios and electronic structures for metal sensing. The CDs obtained from calcination at 700 °C exhibited the highest photoluminescence (PL) quantum yield (QY) of 11.8% among all the samples treated at different temperatures. These CDs had a high degree of graphitization, which resulted in a strong π-π* electron transition, and hence in a high QY. The strong photoluminescence of the CDs could be used to sense the metal ions Ag, Sr, Fe, Fe, Co, Ni, Cu, and Sn by monitoring their PL intensity at an excitation wavelength of 320 nm. The metals inhibited the PL intensity in the order Ag > Fe, Fe, Ni > Sr, Co, Cu, Sn, which demonstrated that the CDs exhibited high metal ion detection capability and selectivity. The detection of Fe using CDs was performed in the range of 10-100 ppm with a LOD (limit of detection) value of 0.380 ppm. Theoretical calculations demonstrated that Ag, Sr, and Sn induced charge transfer excitation and that Fe and Ni induced d-d transitions via complexation with the sp clusters. The charge transfer excitation and d-d transitions hindered the π-π* transition of the sp clusters, leading to a quenching effect. On the other hand, Li, Na, and K ions did not alter the π-π* transition of the sp clusters, resulting in a negligible quenching effect. In summary, the oxidation level and electronic structure of CDs derived from bitter tea residue could be tailored, and the CDs were shown to be a facile, sustainable, and eco-friendly material for metal sensing.
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http://dx.doi.org/10.1016/j.envres.2021.111008 | DOI Listing |
Nanotoxicology
January 2025
Department of Fisheries, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran.
Titanium dioxide nanoparticles (TiONPs) as an emerging pollutant in aquatic environments can interact with metals reducing or enhancing their toxicity in these environments. This study examined and compared the toxic effects of mercury ions (Hg ions) on immobilization percentage, fatty acid profile, and oxidative stress of nauplii, individually (Hg) and simultaneously in the presence of 0.10 mg.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Harbin Institute of Technology (Shenzhen), Department of Materials Science and Engineering, College Park, Building C, 404, Shenzhen, CHINA.
Conventional SEI in aqueous Zn-ion batteries mainly acts as a physical barrier to prevent HER, which is prone to structural deterioration stemming from uneven Zn deposition at high current densities. Herein, we propose an in-situ structural design of polymer-inorganic bilayer SEI with a proton holder feature by aniline-modulated electrolytes. The inner ZnF2 with high stiffness and strength effectively suppresses Zn dendrites.
View Article and Find Full Text PDFSmall Methods
January 2025
Research Institute of Frontier Science, Southwest Jiaotong University, Chengdu, 610031, P. R. China.
Commercial 3D zinc foam anodes with high deposition space and ion permeation have shown great potential in aqueous ion batteries. However, the local accumulated stress from its high-curvature surface exacerbates the Zn dendrite issue, leading to poor reversibility. Herein, we have employed zincophilic N-doped carbon@Sn composites (N-C@Sn) as nano-fillings to effectively release the local stress of high curvature surface of 3D Zn foams toward dendrite-free anode in aqueous zinc ion battery (AZIB).
View Article and Find Full Text PDFAdv Mater
January 2025
Center of Energy Storage Materials and Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid-State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
The energy density of layered oxides of Li-ion batteries can be enhanced by inducing oxygen redox through replacing transition metal (TM) ions with Li ions in the TM layer. Undesirably, the cathodes always suffer from unfavorable structural degradation, which is closely associated with irreversible TM migration and slab gliding, resulting in continuous capacity and voltage decay. Herein, attention is paid to the Li ions in the TM layer (Li) and find their extra effects beyond inducing oxygen redox, which has been rarely mentioned.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
A concise and convergent synthesis of the isosteroidal alkaloids veratramine and 20--veratramine has been accomplished. A Horner-Wadsworth-Emmons olefination joins two chiral building blocks of approximately equal complexity and a transition-metal catalyzed intramolecular Diels-Alder cycloaddition-aromatization cascade constructs the tetrasubstituted arene. Other key steps include a highly diastereoselective crotylation of an -sulfonyl iminium ion and an Eschenmoser fragmentation.
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