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The use of concentrated solar energy for the reduction of CuO in H2
摘要： The reduction of copper (II) oxide was carried out under concentrated solar radiation in a stream of gaseous mixture 5/95 v/v H2/N2 in a 1.5 kW thermal power vertical axis parabolic concentrator at the PROMES-CNRS solar facility (Odeillo-Font Romeu, France). Experiments were performed using a commercial oxide in two different forms, powdered and compacted specimens. The reduction of CuO to elemental Cu was more effective for compacted specimen yielding a dendrite microstructured metallic copper with an electrochemical behavior similar to that exhibited by the commercial metal. In the case of powdered specimen, a composite metal/oxide (Cu/Cu2O) block was obtained as a macroporous material. The reduction process of CuO under concentrated solar energy tracks through the formation of Cu2O as the only intermediate phase, which was evidenced by X-ray diffraction and scanning electron microscopy.
关键词： Copper,Concentrated solar energy,Hydrogen,Copper oxide reduction
更新于2025-09-19 17:15:36
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Hierarchical Micro/Mesoporous Copper Structure with Enhanced Antimicrobial Property via Laser Surface Texturing
摘要： Copper (Cu) and its alloys have been shown to eradicate a wide range of multidrug-resistant microbes upon direct contact. In this study, a facile one-step laser texturing (LT) process is demonstrated to effectively enhance the bactericidal properties of copper surfaces via concurrent selective modification of surface topography and chemistry of laser textured copper (LT-Cu). Surface morphology and elemental composition are analyzed via field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. Surface area and pore size of LT-Cu is determined by Barrett–Joyner–Halenda (BJH) and Brunauer–Emmett–Teller (BET) analysis. It reveals direct formation of mesoporous structures with higher surface oxide (Cu2O and CuO), which provide a highly stable superhydrophilic property to the LT-Cu surfaces. The antibacterial properties of LT-Cu are tested against pathogenic bacterial strains with different concentrations including Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA USA300) at 105 CFU mL?1, and Escherichia coli and Staphylococcus aureus at high bacterial concentrations of 108 CFU mL?1 using standard contact killing tests. The analysis shows that LT-Cu needs 40, 90, 60, and 120 min to completely eradicate the respective bacterial strain. The LT-Cu causes membrane damage to the bacterial cells immediately after exposure. Furthermore, the biocompatibility of LT-Cu is investigated by in vitro immune-staining assays with mammary stromal fibroblasts and T4-2 cells.
关键词： laser texturing,copper,hydrophilic,antibacterial,contact killing,copper oxide
更新于2025-09-19 17:13:59
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Tandem Si Micropillar Array Photocathodes with Conformal Copper Oxide and a Protection Layer by Pulsed Laser Deposition
摘要： This work demonstrates the influence of high-quality protection layers on Si-Cu2O micropillar arrays created by pulsed laser deposition (PLD), with the goal to overcome photodegradation and achieve long-term operation during photoelectrochemical (PEC) water splitting. Sequentially, we assessed planar and micropillar device designs with various design parameters and their influence on PEC hydrogen evolution reaction. On the planar device substrates, a Cu2O film thickness of 600 nm and a Cu2O/CuO heterojunction layer with a 5:1 thickness ratio between Cu2O to CuO were found to be optimal. The planar Si/Cu2O/CuO heterostructure showed a higher PV performance (Jsc = 20 mA/cm2) compared to the planar Si/Cu2O device, but micropillar devices did not show this improvement. Multifunctional overlayers of ZnO (25 nm) and TiO2 (100 nm) were employed by PLD on Si/Cu2O planar and micropillar arrays to provide a hole-selective passivation layer that acts against photocorrosion. A micropillar Si/ITO-Au/Cu2O/ZnO/TiO2/Pt stack was compared with a planar device. Under optimized conditions, the Si/Cu2O photocathode with Pt as a HER catalyst displayed a photocurrent of 7.5 mA cm?2 at 0 V vs RHE and an onset potential of 0.85 V vs RHE, with a stable operation for 75 h.
关键词： tandem photocathode,copper oxide,Si micropillar array,hydrogen evolution reaction,pulse laser deposition
更新于2025-09-19 17:13:59
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Bacterial killing efficacy of synthesized rod shaped cuprous oxide nanoparticles using laser ablation technique
摘要： Recent interests with copper nanoparticles (Cu-NPs) has arisen because of its low cost and antibacterial properties, as it may be one of the very important alternatives to silver NPs. Pulsed laser ablation of a solid target (copper) in liquid media is used to synthesize colloidal oxide copper (Cu2O and CuO NPs) NPs. These oxides of copper NPs were synthesized using Nd:YAG laser energy to maintain a 40 mJ/pulse wavelength at 1064 nm. During the synthesis of colloidal NPs only two conditions were opted, employing double distilled water (without PEG) and 10% preparation of PEG. Both NPs were prepared under the similar parameters such as optimized instrument settings, laser energy and time of laser exposure (1 h ablation). Further, these copper oxide NPs were characterized by advance technologies including UV–visible, X-ray diffraction, transmission electron microscopy and attenuated total reflection Fourier transform infrared spectroscopy techniques. The significant antibacterial properties of synthesized materials were also observed. The cuprous oxide NPs, showed remarkable antibacterial effect conducted using disc diffusion techniques. The minimum inhibitory concentration and minimum bactericidal concentration of synthesized Cu2O NPs were recorded as 120 and 140 μg/L respectively against Staphylococcus aureus used as positive control. Therefore, based on the findings of present study Cu2O NPs can be exploited as stable antimicrobial agents for multipurpose uses.
关键词： Polyethylene glycol,Laser ablation,Antibacterial,UV–visible,Copper oxide NPs
更新于2025-09-19 17:13:59
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Effect of Decomposition of CuO Film on Ignition of Organic Explosives by a Laser Pulse
摘要： This work presents experimental results of the PETN ignition in a three-layer system: glass – copper oxide (CuO) – explosive materials (EM) and results of numerical simulations of the ignition of PETN, RDX, HMX, and TATB with a CuO film heated by a YLS-150 fiber laser with a pulse duration of 20 ms. In the numerical simulations, the endothermic reaction of decomposition of the CuO film and decomposition reaction of EM were taken into account. It has been established that the endothermic effect of the CuO decomposition reaction increases the dynamic ignition delay time of EM. The expression for an estimation of width of a reaction layer in EM at heating by a constant heat stream is obtained. Calculations have shown that the dynamic threshold of ignition of organic explosives by laser pulse in a three-layer system (glass – CuO – EM) has a minimum for the thickness of the copper oxide film of 5 mm. The density of the critical ignition energy of an explosive laser pulse increases in the sequence of PETN, RDX, HMX, and TATB. The calculated dependence of the PETN dynamic ignition delay time on the thickness of the CuO film is consistent with the experimental data.
关键词： PETN,explosive,RDX,TATB,copper oxide,HMX,laser ignition,simulation
更新于2025-09-11 14:15:04
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Zirconium distribution in solution-derived BaZrO3 - YBa2Cu3O7-δ epitaxial thin films studied by X-ray photoelectron spectroscopy
摘要： Superconducting YBa2Cu3O7-δ films with different amounts of BaZrO3 nanoinclusions were deposited on SrTiO3(001) by low-fluorine chemical solution deposition with the aim of introducing artificial vortex pinning centres. The Zr concentration over the film thickness could be determined by X-ray photoelectron spectroscopy combined with Ar+ ion etching. The Zr/Y ratio has a constant behaviour in the film's bulk. Zr segregation occurs near the surface and Zr diffusion into the substrate is observed near the interface. Conversely, Sr and Ti from the substrate diffuse into the films. Y3d lineshape analysis and X-Ray Diffraction data pointed out that Ti diffusion causes the formation of Y-Ti-O based spurious phases.
关键词： Chemical solution deposition,X-ray photoelectron spectroscopy,Vortex pinning,Yttrium barium copper oxide,Barium zirconate
更新于2025-09-10 09:29:36
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Photo-electrochemical stability of copper oxide photocathodes deposited by reactive high power impulse magnetron sputtering
摘要： Copper oxide thin films were deposited by a reactive high power impulse magnetron sputtering (r-HIPIMS) on glass substrates with a SnO2:F (FTO) layer. The pulse magnetron discharge was analyzed via the radio frequency (RF) Sobolewski probe, used for the time-resolved measurement of ion flux density on the substrate. Pulsed discharge current and voltage waveforms were analyzed. It was found that the pulse magnetron discharge worked in a self-sputtering mode with a stable or slightly growing discharge current after pulse discharge stabilization. As-deposited copper oxide films exhibited a certain degree of crystallinity, as identified by XRD, which was further improved after postdeposition annealing at 550 oC in the air. After annealing, the mixture of CuO and Cu2O crystallites was usually found in the films and in a few cases CuO0.96 phase was detected. Deposited films exhibited a p-type conductivity and relatively high photocurrents in the cathodic region after the postdeposition annealing. The highest photocurrent density of ip ≈ 1.1 mA cm-2 at potential -500 mV vs. Ag/AgCl was detected for films with a thickness of 1200 nm.
关键词： magnetron discharge,photocurrent,high power impulse magnetron sputtering,reactive sputtering,copper oxide,photocathode
更新于2025-09-10 09:29:36
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Biosynthesis and characterization of copper oxide nanoparticles from indigenous fungi and its effect of photothermolysis on human lung carcinoma
摘要： In this report, copper oxide nanoparticles (TA-CuO NPs) were synthesized using cell-free extract of Trichoderma asperellum and assessed their photothermal induced anticancerous activity. The fungal mediated TA-CuO NPs was confirmed by the surface plasmon resonance at 285-295 nm. The amide (C=O) and aromatic (C=C) groups in secondary metabolites of the extract was found to be an encapsulating or reducing agents for TA-CuO NPs, as indicated by IR spectra. Crystalline nature by cubic face-centered structure of the TA-CuO NPs was confirmed by XRD and their size ranges from 10 to 190 nm and an average of 110 nm by particle size analyzer (PSA). The Ultra HRSEM study revealed spherical shaped TA-CuO NPs. The FETEM results were also in strong agreement with PSA and UHR SEM. The survey-scan spectrum of XPS indicated the presence of C1s (47.83%), Cu2p (16.11%), Na1s (2.2%) and O1s (33.86%). The cell death was significantly found higher in photothermal induced by near-infrared laser (TA-CuO NPs-NIR) treated than that of TA-CuO NPs treatment. The level of ROS (35.62 %) was higher in the treated cells than that of the untreated control, in accordance with the nucleus damage and losses in the mitochondrial membrane potential (ΔΨm). the upregulation of Bcl-2 in untreated cells and Cas-3 in TA-CuO NPs-NIR treated cells was confirmed by western blot analysis. This work agreed the potential biogenic TA-CuO NPs for promising in vitro photothermolysis of cancer cells, for the development of anticancer nanotherapeutics.
关键词： photothermal activity,Trichoderma,copper oxide nanoparticles,human lung carcinoma,apoptosis,anticancer
更新于2025-09-10 09:29:36
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Microwave dual-mode resonators for coherent spin-photon coupling
摘要： We implement superconducting Yttrium barium copper oxide planar resonators with two fundamental modes for circuit quantum electrodynamics experiments. We first demonstrate good tunability in the resonant microwave frequencies and in their interplay, as emerges from the dependence of the transmission spectra on the device geometry. We then investigate the magnetic coupling of the resonant modes with bulk samples of 2,2-diphenyl-1-picrylhydrazyl organic radical spins. The transmission spectroscopy performed at low temperature shows that the coherent spin-photon coupling regime with the spin ensembles can be achieved by each of the resonator modes. The analysis of the results within the framework of the input-output formalism and by means of entropic measures demonstrates coherent mixing of the degrees of freedom corresponding to two remote spin ensembles and, with a suitable choice of the geometry, the approaching of a regime with spin-induced mixing of the two photon modes.
关键词： coherent spin-photon coupling,circuit quantum electrodynamics,Microwave dual-mode resonators,superconducting Yttrium barium copper oxide,2,2-diphenyl-1-picrylhydrazyl organic radical spins
更新于2025-09-10 09:29:36
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Synthesis of copper oxide nanowires with an emphasis on analyzing the effect of oxidation time on the growth of nanowires
摘要： Copper nanowires offers a wide variety of applications in domains like electronics, energy harvesting and heat transfer. Here, spherical copper has been thermally oxidized to produce nano-wired particles. The length and diameter of these CuO nanowires are in the range of approximately 3–15 μm and 100–300 nm respectively. SEM images of the oxidized copper particles were examined to understand the effect of oxidation time on the length and population density of the nanowire. Oxidation times were set from 15 min to 4 h. We report a direct relation between oxidation time and the population density of the nanowires. An increase in length of the wires was observed up to an oxidation time of 3 h, however, further increase in oxidation time did not signi?cantly contribute to an increased length of nanowires. XRD and TGA was performed to identify the phases of CuO and oxidation rate of Cu respectively.
关键词： thermal oxidation,copper nanowires,metal oxides,copper oxide nanowires
更新于2025-09-09 09:28:46