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The shielding properties of a Cu-doped Ni–Zn polycrystalline ferrite in the frequency range 1 MHz to 1 GHz were explored. Samples of composition (Cu0.12Ni0.23Zn0.65)Fe2O4 were prepared by the traditional ceramic route. The complex relative permittivity () and permeability () of the absorber ceramics were measured, and the minimum reflection-loss , matching frequency , matching thickness and bandwidth for were calculated using the theory of the absorbing wall. Effect of the main process parameters (pressing pressure P, sintering temperature T, and sintering time t) on the electromagnetic properties and microwave-absorbing characteristics was deeply investigated. The rise of the three selected process parameters was observed to improve the sintered microstructure of the final specimens (monitored by the relative density and the average grain size G), provided that abnormal grain growth does not occurred. The increase in sintered relative density and average grain growth modifies complex permeability and permittivity in the explored frequency range, enhancing the shielding properties of the material. Se han analizado las propiedades de blindaje de una ferrita policristalina de Ni–Zn dopada con Cu en el rango de frecuencia de 1 MHz-1 GHz. Las muestras de composición (Cu0.12Ni0.23Zn0.65)Fe2O4 se prepararon por la ruta tradicional cerámica, midiendo la permitividad () y la permeabilidad () relativas complejas de las cerámicas absorbentes y se calcularon, utilizando la teoría de la pared absorbente, la pérdida por reflexión mínima , la frecuencia a la que se produce esta mínima , el espesor óptimo de pieza y el ancho de banda para . Se ha llevado a cabo una investigación rigurosa del efecto de los principales parámetros del proceso (presión de prensado P, temperatura de sinterización T y tiempo de sinterización t) sobre las propiedades electromagnéticas y los parámetros característicos de estos absorbedores, observándose que el aumento de los tres parámetros de proceso seleccionados mejoran la microestructura final de las muestras sinterizadas (monitorizadas por la densidad relativa y el tamaño medio de grano G siempre que no se produzca un crecimiento anormal del grano. El aumento de la densidad relativa y el tamaño medio de grano de las piezas sinterizadas modifican la permeabilidad y la permitividad complejas en el rango de frecuencia explorado, mejorando las propiedades de blindaje del material. This study has been supported by Ministerio de Economía y Competitividad (Spain) through grant number (MAT2016-76320-R) and by Universitat Jaume I (Spain), grant numbers (UJIB2017-48 and UJIB2020-13). Complex relative permeability and permittivity determination were carried out at the central facilities (Servei Central d’Instrumentació Científica) of the Universitat Jaume I.

Herein, we investigated the influence of sulfur (S) addition on the phase formation behavior and thermoelectric transport properties of n-type Cu0.008Bi2Te3. A complete single phase of rhombohedral Bi2Te3 was formed in Cu0.008Bi2Te2.8S0.2, whereas a mixture of Bi2Te3 and Bi2Te2S1 phases was generated at higher S contents. We elucidated the complex effects of S substitution at Te-site on transport properties of Cu0.008Bi2Te3; (1) increase in density-of-states effective mass, (2) decrease in weighted mobility ratio, (3) reduction in lattice thermal conductivity, and (4) reduction in bipolar thermal conductivity. Despite the slight deterioration in electronic transport properties, a maximum thermoelectric figure of merit (zT) of 0.82 was achieved at 400 K in Cu0.008Bi2Te2.8S0.2 due to the synergetic effect of intensified point defect phonon scattering in a wide temperature range and suppressed bipolar thermal conduction at elevated temperatures.

In this work undoped and Cu doped SnS film at 4% and 8% were deposited onto glass substrates by spray pyrolysis technique in order to investigate the effect of Cu doping on their physical properties. Surface investigations showed that Cu doping reduced the surface roughness of SnS films from 36.5 nm to 8.8 nm. XRD studies revealed that all films have recently solved large cubic phase of SnS (p-SnS) with a- lattice of 11.53 Å and Cu doping led to reduction in crystallite size from 229 Å to 198 Å. Additionally, all deposited films were found to be under compressive strain. Optical band gaps of SnS:Cu varied in the range of 1.83 eV-1.90 eV. Hall-effect measurements exhibited that all film have p-type conductivity with low hole concentration (~10 11 -10 12 cm -3 ) and high electrical resistivity (~10 4 -10 5 Ωcm).

In this study, we proposed Cu-doped TiO2, prepared by the alkaline and heat treatment of titanium (Ti) metal, for use in dental applications because of its bone-bonding and antibacterial properties generated by the release of Cu ions and visible-light-responsive photocatalysis. We successfully prepared Cu-doped TiO2 on a Ti chip surface with a Cu content of 7 at.%. The apatite-forming ability of the Cu-doped TiO2 was evaluated using a simulated body fluid and it was found that apatite formation occurred. Hence, we concluded that Cu-doped TiO2 exhibits bone-bonding properties. The antibacterial properties of Cu-doped TiO2 for Escherichia coli were higher than those of non-doped TiO2 under visible light irradiation. The enhanced antibacterial effect was mainly caused by the visible-light-responsive photocatalysis of Cu-doped TiO2. We confirmed that the reactive oxygen species generated by the visible-light-responsive photocatalysis of Cu-doped TiO2 were hydroxyl radicals formed by the reaction of hydroxide ions (OH−) and holes (h+). Our findings are useful for the development of novel bioactive TiO2-based coatings and bulk materials with antibacterial properties by Cu doping.

Li Q., Yang J., Li J., et al. Antibacterial Cu-doped calcium phosphate coating on pure titanium. Materials Transactions 62, 1052 (2021); https://doi.org/10.2320/matertrans.MT-M2021005., Cu-doped amorphous calcium phosphate (ACP) coatings were fabricated on the surface of pure titanium (Ti) by electrochemical deposition at initial electrolyte temperatures of 35, 45, and 55°C. The antibacterial activities of the coatings were then evaluated by the plate counting method using Escherichia coli as the indicator. The Cu concentrations on the surfaces of samples are increased from 6.90 to 15.05 mass% as initial electrolyte temperature is increased from 35 to 55°C. The Cu-doped ACP coatings show that they can fully inhibit the growth of E. coli.

Project Anillo en Ciencias y Tecnologia Topicos Mineria ACM170003 CONICYT-PIA Project AFB180004

The results of a study of the wear resistance of coatings based on cuprides of titaniumin the temperature range of 20-600 С are presented. It is shown that the wear resistance of nickel-doped coatings exceeds the wear resistance of binary coatings. With an increase in the Ni content of more than 10 %, their resistance to wear increases slightly.

An experimental study to determine the effect of Cu doping on structural properties of ZnO nanoparticle has been conducted. Zn1-xCuxO (CZO) were prepared by co-precipitation method by varying Cu concentration with x = 0.00, 0.10, 0.11 and 0.12. The structural properties of the CZO sample were characterized by X-Ray diffraction (XRD) and X-ray Absorption Spectroscopy (XAS), which consist of XANES (X-ray Absorption Near-Edge Spectroscopy) and EXAFS (Extended X-ray Absorption Fine Structure). XAS measurements were performed in the energy of Cu K-edge and Zn K-edge using synchrotron radiation at SLRI (Synchrotron Light Research Institute) in Thailand. Both Cu K-edge and Zn K-edge XANES spectra indicate that the oxidation states of Cu and Zn ions are 2+. Analysis of XRD data with refinement method using Rietica software confirms the presence of Cu as doping in ZnO host lattice with the crystallite size ranging between 26 and 44 nm. Moreover, it shows that the obtained CZO samples are polycrystalline with (002) predominant reflection and exhibit a hexagonal wurtzite structure.

In the present study, Cu (2–12%) doped MgO was synthesized and characterized by SEM, XRD, EDX, and FTIR spectroscopy. The Cu concentration significantly affected the band gap and particle size, which ranged from 4.63 to 3.78 eV and from 27.2 to 79 nm, respectively. In addition, the photocatalytic activity (PCA) of Cu-doped MgO was monitored by the photocatalytic destruction of disperse red F3BS coralene dye, and four reaction variables such as dye concentration, catalyst dose, hydrogen peroxide concentration, and irradiation time, respectively, were optimized by response surface methodology (RSM). Dye degradation was significantly affected by these process variables, and a degradation rate of up to 93% was achieved under optimized conditions. The wastewater samples were also treated under optimized conditions and water quality variables, i.e., chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were significantly improved after treatment. Cu-doped MgO exhibited excellent PCA under the solar-light exposure for the degradation of disperse red F3BS dye, which can be employed for the treatment of dye-containing effluents.

The adsorption properties of formaldehyde on the Cr and Cu doped ZnO surface were investigated by using the density functional theory (DFT). The results showed that the binding capacity of the ZnO sensor material to formaldehyde was improved by doping with Cr atoms. Meanwhile, doping Cu atoms showed no obvious enhancement on the formaldehyde binding capacity. The binding distance of formaldehyde to the Cr and Cu-doped ZnO was calculated to be 1.937 and 2.031 A, respectively, with the binding energy of 0.775 and 0.376 eV. After doping, the width of the conduction band increased and impurity levels appeared. The adsorption process of formaldehyde on the Cr and Cu doped ZnO surface belongs to physical adsorption. It is expected that the calculated results reported in the present study can provide worthwhile references for the theoretical investigations and future design of ZnO material for enhancing its performance by doping with different elements.

In this work, Pure and Cu: doped titanium dioxide nano-powder was prepared through a solid-state method. the dopant concentration [Cu/TiO2 in atomic percentage (wt%)] is derived from 0 to 7 wt.%. structural properties of the samples performed with XRD revealed all nanopowders are of titanium dioxide having polycrystalline nature. Physical and Morphological studies were conducted using a scanning electronic microscope SEM test instrument to confirm the grain size and texture. The other properties of samples were examined using an optical microscope, Lee's Disc, Shore D hardness instrument, Fourier-transform infrared spectroscopy (FTIR), and Energy-dispersive X-ray spectroscopy (EDX). Results showed that the thermal conductivity increased with the weight fraction of the Cu element increasing.

We have investigated the effect of copper substitution on the structure, cation valence, and magnetic properties of the double perovskite La2MnCoO6. La2Mn1–xCuxCoO6 (0 ≤ x ≤ 0.4) were synthesized b...

Quenching effects on electrical and piezoelectric properties were investigated for Cu-doped (Bi1/2Na1/2)TiO3 (BNT)-based solid solution systems, 0.90(Bi1/2Na1/2)TiO3–0.06BaTiO3–0.04(Bi1/2Li1/2)TiO3 (BNLBT), aiming to increase the depolarization temperature Td without deteriorating the piezoelectric properties. A dense BNLBT ceramics doped with CuO 1.0 wt% was fabricated by a conventional ceramic fabrication process with a low-sintering temperature at 940 °C, which is 200 °C lower than those for non-doped BNLBT ceramics. In addition, the CuO-doped BNLBT ceramic was quenched immediately after the sintering process at 940 °C, and the piezoelectric constant and Td were measured. The Td values of CuO-doped BNLBT systems with and without quenching were 143 and 78 °C, respectively. This showed that Td Cu-doped ceramics increased by approximately 60 °C due to quenching. In addition, the electromechanical coupling factors k33 of quenched and non-quenched Cu-doped BNLBT ceramics were approximately 0.58, showing no significant deterioration of piezoelectric activity caused by quenching.

Cu-doped TiO2 photocatalysts [Cu-(1 to 10) atom %] synthesized by the sol–gel method and thoroughly characterized using several techniques were evaluated for photocatalytic reduction of CO2 under a...

Cu serves as a co-catalyst, an electron mediator, and a dopant leading to a high enhancement in the photocatalytic activity of Cu-ZnO/Cu/g-C3N4 Z-scheme photocatalyst.

The thermal behavior of Cu-doped TiO2 gels obtained by the sol-gel method was investigated by thermogravimetric and differential thermal analysis (TG/DTG/DTA) and differential scanning calorimetry (DSC) measurements. The comparative investigation of the structure and morphology of the as-prepared gels and of the nanopowders obtained by annealing them was realized by transmission electron microscopy (TEM), Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Significant differences were noticed depending on the amount of dopant (0.5 or 2.0 mol % CuO). A higher dopant concentration resulted in a more complex decomposition of the sample. This behavior was associated with the formation of various molecular species in the sol-gel solutions before gelation, determined by the different amount of the dopant used.

Chemical looping hydrogen (CLH) production, or hydrogen production combined with CO2 capture, is becoming an emerging alternative technology that has attracted much attention. Iron-based oxygen car...

Cu-doped TiO2 having a brookite phase and showing enhanced visible light photocatalytic activity was synthesized using a mild solvothermal method. The as-prepared samples were characterized by various techniques, such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy. Photocatalytic activity of Cu-doped brookite TiO2 nanoparticles was evaluated by photodegradation of methylene blue under visible light irradiation. The X-ray diffraction analysis showed that the crystallite size of Cu-doped brookite TiO2 samples decreased with the increase of Cu concentration in the samples. The UV-Vis diffuse reflectance spectroscopy analysis of the Cu-doped TiO2 samples showed a shift to lower energy levels in the band gap compared with that of bare phase brookite TiO2. Cu doped brookite TiO2 can obviously improve its visible light photocatalytic activity because of Cu ions acting as electron acceptors and inhibiting electron-hole recombination. The brookite TiO2 sample with 7.0 wt.% Cu showed the highest photocatalytic activity and the corresponding degradation rate of MB (10 mg/L) reached to 87 % after visible light illumination for 120 min, much higher than that of bare brookite TiO2 prepared under the same conditions (78 %).

We report the fabrication and characterization of varying concentration (x) of copper (Cu)-doped TiO2 nanocomposites [Cu( x )TiO2(1- x )] exploring the photocatalytic properties for sunscreen appli...

Thin films of ZnO nano crystalline doped with different concentrations (0, 6, 9, 12, and 18 )wt. % of copper were deposited on a glass substrate via pulsed laser deposition method (PLD). The properties of ZnO: Cu thin-nanofilms have been studied by absorbing UV-VIS, X-ray diffraction (XRD) and atomic force microscopes (AFM). UV-VIS spectroscopy was used to determine the type and value of the optical energy gap, while X-ray diffraction was used to examine the structure and determine the size of the crystals. Atomic force microscopes were used to study the surface formation of precipitated materials. The UV-VIS spectroscopy was used to determine the type and value of the optical energy gap.

The present work focuses on the deposition of Cu, Co, Mn and Mo doped zinc oxide thin films onto glass substrates and investigates their photocatalytic dye degradation abilities at different pH values of the test dye solution. The effect of point of zero charge on the photocatalytic activity was studied. This study demonstrates how the pH of the dye solution plays a crucial role on the dye degrading mechanism. The optimum pH for achieving the best dye degrading efficiency was estimated for all the four doped ZnO films for cationic dyes and the procedure for extending this idea to the anionic dyes was also addressed.

Pure and copper doped tin oxide nanoparticles were synthesized by co-precipitation method and are characterized by XRD, SEM, EDAX, UV-Visible, photoluminescence, and FT-IR analysis techniques. Tetragonal rutile structure is confirmed from XRD and the crystallite size is found to be between 3.8nm and 4.8nm. The optical band gap is observed from UV-Vis spectrum and is found to be 3.99eV and 3.93eV for tin oxide and copper doped tin oxide respectively. The optical band gap of pure and Copper doped tin oxide were blue shifted due to quantum confinement. Photoluminescence spectrum shows UV, blue and green emission peaks.

Cu-doped Mn3O4 and Mn-doped CuO (CMO@MCO) mixed oxides with isolated phases together with pristine Mn3O4 (MO) and CuO (CO) have been synthesized by a simple solution process for applications in electrochemical supercapacitors. The crystallographic, spectroscopic, and morphological analyses revealed the formation of all of the materials with good crystallinity and purity with the creation of rhombohedral-shaped MO and CMO and a mixture of spherical and rod-shaped CO and MCO nanostructures. The ratio of CMO and MCO in the optimized CMO@MCO was 2:1 with the Cu and Mn dopants percentages of 12 and 15%, respectively. The MO-, CO-, and CMO@MCO-modified carbon cloth (CC) electrodes delivered the specific capacitance (Cs) values of 541.1, 706.7, and 997.2 F/g at 5 mV/s and 413.4, 480.5, and 561.1 F/g at 1.3 A/g, respectively. This enhanced Cs value of CMO@MCO with an energy density and a power density of 78.0 Wh/kg and 650.0 W/kg, respectively, could be attributed to the improvement of electrical conductivity induced by the dopants and the high percentage of oxygen vacancies. This corroborated to a decrease in the optical band gap and charge-transfer resistance (Rct) of CMO@MCO at the electrode/electrolyte interface compared to those of MO and CO. The net enhancement of the Faradaic contribution induced by the redox reaction of the dopant and improved surface area was also responsible for the better electrochemical performance of CMO@MCO. The CMO@MCO/CC electrode showed high electrochemical stability with a Cs loss of only ca. 4.7%. This research could open up new possibilities for the development of doped mixed oxides for high-performance supercapacitors.

In the synthesis of organic compounds, heterogeneous catalysts have gained significance versus their homogeneous counterparts, due to both environmental and economic concerns. 1–4 Homogeneous catal...

Al doped and Cu doped ZnO NRAs/Graphene composite material are synthesized by introducing the concentrations of 0%, 2%, 4%, 6%, 8% using hydrothermal method, and their structure and morphology are ...

In this study, the effective complex magnetic permeability-imaginary part ( μ e f f ' ' ) of a Cu doped-NiZn polycrystalline ferrite used as EMI suppressor has been quantitatively related to microstructural parameters. It has been observed that μ e f f ' ' strongly depends on average grain size ( G ) of the compact, but also on its relative density ϕ : the higher grain size and density the higher μ e f f ' ' . A mathematical relationship between μ e f f ' ' and average grain size and densification has been proposed and tested, accurately reproducing the experimental results. The use of densification concept allows to compare the wide range of microstructures tested and includes a lower value of relative density (estimated around 0,56) below which μ e f f ' ' is virtually zero. The grain boundary thickness ( δ ) has been estimated around 2 nm which is in agreement with experimental results reported in this work and with those found in literature.