Enhanced cyclic performance initiated via an in situ transformation of Cu/CuO nanodisk to Cu/CuO/Cu2O nanosponge

An Ultralight Capillary-Driven Heat Pipe

Capillary-driven heat pipes are an effective thermal solution for compacting electronic cooling systems. We advance such a heat pipe thermal solution with ultralightweighting for mobile applications. In our advancement, the envelope that encapsulates the phase-change process of a working fluid is fabricated via electroless plating being ∼40 μm thick. Furthermore, the wick structure that transports condensate to a heat source via capillarity is also electroless-plated onto the envelope's inner surfaces, creating a 100-μm-thick, microporous layer. This wick structure is sequentially superhydrophilized by blackening that forms a nanotexture on the microporous wick layer. An effective density of our prototype ultralight heat pipes (uHPs), as a measure of lightweighting, indicates, on average, a remarkable 73% weight reduction of commercial counterparts with sintered copper powder wick in similar exterior dimensions (e.g., ∼2.7 g, compared to ∼10.0 g) while providing equivalent heat spreading. Furthermore, the uHP operates at a 25% lower evaporator temperature, due to additional heat rejection to the surroundings through the ultrathin-walled envelope and wick.

Second phase Cu2O boosted photocatalytic activity of fluorine doped CuO nanoparticles

The photocatalytic activity of fluorine (F) doped CuO nanoparticles (NPs) prepared employing modified sol-gel process was investigated here in this study. Structural and elemental characterization using XRD and XPS data confirmed successful incorporation of F as dopant. F doping led to lattice distortion and reduced crystallinity with smaller crystallite size while promoting the emergence of Cu2O as the second phase. Morphological analysis showed irregularly shaped, fused particles with a decreasing particle size trend upon doping. Addition of hydrogen peroxide generated hydroxyl radicals (OH˙) under ultra-violet (UV) light, which effectively degrades pollutants by facilitating the photocatalytic kinetics. Photocatalytic activity of all the nanoparticles was examined against Rhodamine B (Rh B) dye and most efficient degradation (97.78%) was observed for 3 mol% F dopant concentration. The emergence of Cu2O phase for doping beyond 1 mol% F doped CuO might be the prime reason to enhance its degradation performance. Conversely, 5 mol% doping caused notable phase changes and decreased degradation rate (88.05%) due to increased recombination rate in presence of metallic copper. The ability of F doped CuO nanoparticles to disintegrate organic contaminants by producing reactive oxygen species when exposed to UV light suggests their potential effectiveness in applications such as dye degradation, water purification, and environmental sustainability.

In Situ Partial Sulfidation for Preparing Cu/Cu2−xS Core/Shell Nanorods with Enhanced Photocatalytic Degradation

Herein, we report an approach to prepare Cu/Cu2−xS core/shell nanorods by in situ sulfidation of copper nanorods. Firstly, copper nanorods with tunable longitudinal surface plasmon resonances were synthesized by a seed-mediated method using Au nanoparticles as seeds. A convenient in situ sulfidation method was then applied to convert the outermost layer of Cu nanorods into Cu2−xS, to increase their stability and surface activity in photocatalytic applications. The thickness of Cu2−xS layer can be adjusted by controlling the amount of S source. The Cu/Cu2−xS core/shell nanorods exhibits two characteristic surface plasmon resonances located in visible and near-infrared regions, respectively. The photocatalytic performances of Cu nanorods and their derivatives were evaluated by measuring the degradation rate of methyl orange dyes. Compared with Cu nanorods, the Cu/Cu2−xS core/shell nanorods demonstrate more than a 13.6-fold enhancement in the degradation rate at 40 min. This work suggests a new direction for constructing derivative nanostructures of copper nanorods and exploring their applications.