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Controlled Synthesis of Coral-Like CuO Dendrites with Enhanced Photocatalytic Performance
摘要： In this work, coral-like CuO dendrites were successfully synthesized by a solvothermal method in the mixed solvent of distilled water and ethanol with assistance of dodecyl trimethyl ammonium bromide (DTAB). The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis techniques, to investigate their structure and morphology. The coral-like CuO dendrites were about 1 μm in length, with many dendrites pointing to a common center. The influence of experimental conditions on morphology, such as volume ratio of water to ethanol, surfactant DTAB and molar ratio of Na2CO3 and Cu(CH3COO)2, was also discussed. Time-dependent experiment was carried out to explore the formation mechanism while a “particle-sheet-dendrite (PSD)” mechanism was proposed to explain the growth process. The as-prepared CuO dendrites were used to degrade methylene blue (MB) under visible light irradiation in the presence of H2O2, where over 98% of methylene blue (MB) was degraded in 1 h. Results from the study demonstrated that the as-prepared coral-like CuO dendrites exhibited enhanced photocatalytic performance and excellent stability and reusability.
关键词： Photocatalytic Performance,Solvothermal Method,Coral-Like CuO Dendrites
更新于2025-09-23 15:21:01
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Microstructure and microhardness of a novel TiZrAlV alloy by laser gas nitriding at different laser powers
摘要： The Ti–20Zr–6.5Al–4V (T20Z, wt%) alloy surface was treated by the process of laser surface nitriding. The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W. All laser-treated T20Z samples show two regions with distinctly different microstructural features, as compared with the untreated substrate: dense TiN dendrites and (a ? b) - Ti (remelting zone, RMZ), nanoscale a laths doped with part of b phase (heat-affected zone, HAZ). The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidi?cation. The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input. In HAZ, the self-quenching effect leads to the formation of nanoscale a laths and the residue of b phase. Microhardness pro?le of different regions was measured from the surface to the interior, and the highest microhardness was obtained (* HV 916.8) in the RMZ, as the laser power was set to 240 W. In the present study, we explained various microstructural characteristics induced by laser surface nitriding treatment.
关键词： TiZrAlV alloy,TiN dendrites,Microstructure,Laser surface nitriding,Microhardness
更新于2025-09-19 17:13:59
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Stable Lithium Deposition Enabled by Acid-Treated g-C3N4 Interface Layer for Lithium Metal Anode
摘要： Li metal has been regarded as one of the most promising anode candidates for high-energy rechargeable lithium batteries. Nevertheless, the practical applications of Li anode have been hampered because of its low coulombic efficiency and safety hazards. Here, acid-treated g-C3N4 with O- and N-containing groups is coated on Li foil through a facile physical pressing method. The O- and N-containing groups cooperate to rearrange the concentration of Li ions and enhance the Li ion transfer. Hence, the cycle and rate performances of acid-treated g-C3N4 coated Li electrodes are greatly improved in symmetric cells, which shows a stable cycling over 400 h at 1 mA cm-2 in ester-based electrolyte and over 2100 h in ether-based electrolyte. As for the Li//LiFePO4 full cells, there is a high capacity retention of 80% over 400 cycles at 1 C. The full cells of Li//S in ether-based electrolyte also exhibit a capacity of 520 mA h g-1 after 400 cycles at 1 C.
关键词： O-containing groups,Artificial protection layer,Li dendrites,Li metal anode,N-containing groups
更新于2025-09-19 17:13:59
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Self-organized spatially separated silver 3D dendrites as efficient plasmonic nanostructures for surface-enhanced Raman spectroscopy applications
摘要： Surface-enhanced Raman spectroscopy (SERS) is a promising optical method for analyzing molecular samples of various nature. Most SERS studies are of an applied nature, indicating a serious potential for their application in analytical practice. Dendritelike nanostructures have great potential for SERS, but the lack of a method for their predictable production significantly limits their implementation. In this paper, a method for controllably obtaining spatially separated, self-organized, and highly-branched silver dendrites via template synthesis in pores of SiO2/Si is proposed. The dendritic branches have nanoscale roughness, creating many plasmon-active “hotspots” required for SERS. The first held 3D modeling of the external electromagnetic wave interaction with such a dendrite, as well as experimental data, confirms this theory. Using the example of a reference biological analyte, which is usually used as a label for other biological molecules, the dendrites’ SERS-sensitivity up to 10?15M was demonstrated with an enhancement factor of 108. The comparison of simulation results with SERS experiments allows distinguishing the presence of electromagnetic and chemical contributions, which have a different effect at various analyte concentrations.
关键词： SERS,plasmonic nanostructures,silver dendrites,hotspots,Surface-enhanced Raman spectroscopy
更新于2025-09-12 10:27:22
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Silicon-silver dendritic nanostructures for the enhanced photoelectrochemical splitting of natural water
摘要： We report on the photoelectrochemical (PEC) splitting of natural water (pH 7) using silicon (Si) nanowires fitted with silver (Ag) dendrites (dendritic nanostructures) as working electrodes (photoanodes). A detailed study of the PEC water splitting process was carried out using linear sweep voltammetry, electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) measurements. The measured photocurrent density of 1.7 mA/cm2 at an external voltage of ?0.6 V under white light illumination demonstrates the efficient decomposition of natural water using dendritic nanostructures as working electrodes. This decomposition is mainly attributed to a significant strengthening of the effective interface between working electrode surface/water and to a decline in the recombination of photoinduced carriers in the presence of Ag dendrites. We propose that the Schottky barrier between Si and Ag dendritic nanostructures favors enhanced photoinduced charge carrier separation. Photoinduced holes in Si are transferred to Ag dendrites (nano branches and leaves) that serve as a charge sink to effectively carry out the PEC oxidation of water. Photoinduced charge carrier separation enhancement was corroborated by the kinetics of our carrier recombination study. We obtained a reasonably long transient period of 80 s for the photoinduced carriers. EIS results show that the charge transfer resistance (150 Ω) of the dendritic nanostructure surface is low enough to promote interfacial charge transfer. This resistance generated a large carrier concentration of ~1.1 × 1020 cm?3 at the working electrode/water interface according to an M-S analysis. An applied bias-photon-to-current-conversion efficiency level of roughly 4% is reported, demonstrating the efficient PEC splitting of natural water.
关键词： Linear sweep voltammetry,Photoinduced charge carrier separation enhancement,Photoelectrochemical,Applied bias-photon-to-current-conversion efficiency,Ag dendrites
更新于2025-09-10 09:29:36
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Analysis of Dendrite Images Formed by Electrochemical Migration in a Semiconductor Sensor
摘要： Dendrites were observed in the failure of semiconductor sensor devices. EDX analysis showed that the dendrites grown from bare sensor dice consisted of tin metal. The tin dendrites exhibited massive and dense branches. Dendrites grown from mechanically decapped parts consisted of silver. The silver dendrites exhibited delicate, lace-like structure. Binary and grey scale images of dendrites were analyzed for fractal dimension number and branch density. The tin dendrites had a higher, statistically significant branch density number than silver, due to tin’s more intricate branching pattern. Fractal numbers can be used to differentiate between tin and silver dendrites, even in the absence of EDX analysis equipment.
关键词： dendrites,fractal characteristics
更新于2025-09-10 09:29:36