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Ultrafine Cu2O/CuO nanosheet arrays integrated with NPC/BMG composite rod for photocatalytic degradation
摘要： A free-standing Cu2O/CuO@nanoporous copper/bulk metallic glass (Cu2O/CuO@NPC/BMG) composite rod with a multimodal hierarchical porous structure has been successfully prepared by a facile two-step synthesis strategy consisting of dealloying and anodizing. The NPC/BMG composite is first fabricated by dealloying of Cu50Zr45Al5 BMG rod. Then the ultrafine Cu2O/CuO nanosheet arrays are synthesized by anodizing of the NPC/BMG rod followed by heat treatment. The as-obtained Cu2O/CuO@NPC/BMG composite possesses a multimodal hierarchical porous structure comprising interconnected pores ranging from micro, meso to macro sizes. It is worth pointing out that there are several “barren lands” without nanosheets grown on the surface of the composite. Further analyses indicate that the microstructures of substrate materials not only dominate the sizes of Cu2O/CuO sheets, but also influence the nucleation and growth of Cu2O/CuO sheets. Meanwhile, the possible formation mechanism of the Cu2O/CuO nanosheets is proposed. Accordingly, the Cu2O/CuO@NPC/BMG composite shows remarkably high photocatalytic degradation performance and excellent cycling stability for RhB due to the multimodal hierarchical porous structure, ultrafine Cu2O/CuO nanosheets in the entire NPC and the integration design strategy.
关键词： Metallic glass,Dealloying,Nanoporous,Anodizing,Nanosheet
更新于2025-11-14 17:03:37
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On-chip sensor solution for hydrogen gas detection with the anodic niobium-oxide nanorod arrays
摘要： Two types of anodic niobium-oxide nanofilms were synthesized via anodization of an Al/Nb bilayer sputter-deposited onto a SiO2-coated Si wafer. Type I nanofilm was composed of a 200 nm thick NbO2 layer holding the upright-standing 650 nm long, 50 nm wide, and 70 nm spaced Nb2O5 nanorods, of 7·109 cm?2 density, whereas the Type II nanofilm had similarly long but bigger Nb2O5 nanorods, 100 nm wide, 220 nm spaced, and of 8·108 cm?2 density, aligned directly on a niobium metal without any buffering oxide layer, which was achieved for the first time. Each film was then incorporated in an advanced 3-D architecture and multilayer layout on a silicon chip comprising 33 microsensors, with variable sizes and tuned electrical characteristics, by combining the high-temperature vacuum or air annealing, sputter-deposition, and lift-off photolithography to form Pt/NiCr top electrodes and a multifunctional SiO2 interlayer, chemical etching, laser dicing, and ultrasonic wire-bonding. The proposed on-chip sensor solution allowed for a sensitive, fast, and highly selective (toward NH3 and CH4) detection of hydrogen gas. Comprehensive gas sensing tests performed for Type II nanofilm ultimately confirmed the presence of a Schottky-type sensing mechanism, the contribution, however, being substantially weaker than that due to reactions over the surface of the oxide nanorods, especially when the rods show a transition from fully to partially depleted states when interacting with H2 gas. The film formation and chip fabrication technologies may be transferable to other PAA-assisted 1-dimensional metal-oxide nanomaterials suitable for on-chip gas sensing.
关键词： niobium oxide nanorods,anodic alumina,hydrogen,Schottky barrier,anodizing,on-chip sensor
更新于2025-09-23 15:23:52
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Differences in the local structure and composition of anodic TiO2 nanotubes annealed in vacuum and air
摘要： This work is dedicated to the influence of thermal treatment procedures in vacuum and air atmosphere on the structural features of multiwalled TiO2 anodic nanotubes (NTs) formed in fluorine-containing ethylene glycol (EG) based electrolyte investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with EDX and electronic nanodiffraction (STEM nanodiffraction), IR and Raman spectroscopy, XPS and ToF SIMS. Using electron nanodiffraction technique, there were estimated TiO2 nanocrystallite sizes for the inner layer of the NTs after annealing in air and vacuum for the first time. The differences in carbon distribution profiles in TiO2 nanotube crosscut after thermal treatments in air and vacuum were discussed. It was found that thermal treatment in vacuum leads to different phase composition of TiO2 NTs IL comparing to annealing in air. A sequential thermal treatment (firstly in vacuum and then in air) enables to remove carbon from TiO2 NTs surface and partly from TiO2 NTs IL and prevent detachment of IL from OL at the same time. The obtained data will be useful for understanding the mechanisms of structural modifications during thermal treatments as well as for functional properties optimization of such nanostructures.
关键词： Anodizing,TiO2 nanotubes,Thermal treatment,Electron nanodiffraction,HAADF-STEM
更新于2025-09-23 15:19:57