Cu-doped ZnO Research Articles

Influence of lithium on Cu-doped ZnO thin films fabricated via sol-gel spin coating technique for improved NO2 gas sensing applications

Influence of lithium on Cu-doped ZnO thin films fabricated via sol-gel spin coating technique for improved NO2 gas sensing applications

Preparation of Copper-Doped Zinc Oxide (CZO) Nanoparticles and CZO/Acrylic Copolymer Emulsion with Polyvinylpyrrolidone (PVP) Coated on Glass Substrate for Optical Properties

This study investigated the effect of copper (Cu) doping content on zinc oxide with varied weight percentages and the dispersion of Cu-doped ZnO (CZO) by adding polyvinylpyrrolidone (PVP), coated on a glass substrate, through a physical assessment and optical property and thermal insulation testing. CZO NPs were synthesized by using the sol–gel method with a zinc acetate precursor. The powder X-ray diffraction (XRD) patterns of the CZO showed that the solid solubility limit was below 5 mol% without a secondary phase. A field-emission scanning electron microscopy (FE-SEM) micrograph demonstrated that the particle size of CZO was in nanoscale with the packing of a quasi-spherical shape. The UV-Vis-NIR reflectance spectra of the powder showed that 1 mol% CZO has the highest near-infrared (NIR) reflectivity in the wavelength 780–2500 nm, with great visible light transmission. The CZO NPs were loaded in acrylic copolymer in different weight percentages ranging from 25 wt% to 75 wt%, the film thickness of the coating was varied from 5 µm to 100 µm, and PVP was added into this nanocomposite polymer to disperse through an ultrasonication method. The results showed that the highest loading of CZO powder in a polymer at 75 wt% in 100 µm of thickness with polyvinylpyrrolidone (PVP) as a dispersant showed better sample dispersion and retained good transparency to the naked eye.

Synthesis and characterization of bi-functional Cu and Ni co-doped ZnO photocatalysts for organic pollutant degradation and antimicrobial activity

The study of visible light active photocatalysts for organic pollutants degradation and antimicrobial activity has gained significant attention in recent years. Herein, we report the synthesis of pure ZnO, Ni-doped ZnO (Ni-ZnO), Cu-doped ZnO (Cu-ZnO), and Cu and Ni co-doped ZnO (CuNi-ZnO) photocatalysts via a facile coprecipitation method. These photocatalyst materials were characterized using various analytical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), photoluminescence (PL), and total organic carbon (TOC) analysis. XRD patterns confirm the presence of a mixed phase in the CuNi-ZnO sample. The presence of Cu, Ni, and Zn in CuNi-ZnO was verified through the XPS spectra. The nanoparticle-like morphology of the CuNi-ZnO photocatalyst was confirmed using HRTEM analysis. The FTIR spectra reveal the chemical bonds present in the materials. UV–visible spectroscopy was employed to determine the band gap of the materials, revealing a value of 3.10 eV for CuNi-ZnO. The mitigation in recombination of excited electrons (e−) and holes (h+) in CuNi-ZnO is validated through photoluminescence (PL) studies. The synthesized materials were used for the degradation of Indigo carmine (IC) dye and antimicrobial activity. The results showed that the optimized CuNi-ZnO sample displayed a better visible light photocatalytic performance (93.32 % IC dye degradation efficiency in 60 min) than the other samples. A notable degree of mineralization was observed with a reduction in total organic carbon (TOC) reaching 65.91 %. Additionally, the photocatalyst showed antimicrobial activity against both S. aureus and E. coli. Furthermore, a plausible visible light photocatalytic mechanism was proposed for the degradation of IC dye using the CuNi-ZnO photocatalyst.

Facile one-pot synthesis of ternary Fe doped Cu-ZnO nanocatalyst: An efficient and recyclable solar light driven photocatalyst

Currently, nanoparticles are regarded as excellent materials for degrading and removing dyes due to their beneficial surface features and chemical reactivity. Herein, Cu doped ZnO (CZ) was co-doped with Fe (FCZ) at different concentrations (2, 3, 4 and 8 wt% with respect to CZ) via simple one-step co-precipitation approach. The structural, surface morphology, surface properties, optical and photocatalytic performance of prepared samples were studied. Due to the doping of Fe, the band gap of CZ reduced from 2.7 eV to 2.29 eV, which is beneficial for absorbing visible light. Among doped CZs, 4 wt% Fe-doped CZ (4FCZ) exhibited 97.1% methylene blue (MB) degradation at neutral pH under 60 min of sunlight exposure. Furthermore, the effect of initial concentration of dye, catalyst load, and pH on the degradation process was investigated. The remarkable photocatalytic activity of 4FCZ nanoparticles can be attributed to their advantageous surface properties, such as their high specific surface area, heterostructure morphology, and mesoporous nature. Scavenger study identified •O2−, e−, and h+ as main reactive species. Pseudo-first order kinetics revealed degradation order: 4FCZ>8FCZ>3FCZ>2FCZ>CZ. 4FCZ showed recyclability with 90.9% MB degradation after three cycles. Mineralization of MB was analysed by COD and LC-MS studies. Fe-doped CZ emerges as a promising, cost-effective wastewater treatment under sunlight without special equipment. This study provides new insights on synthesis of ternary nanocatalyst for dye degradation.

Biological Renewable Cellulose-Templated Zn1-XCuXO/Ag2O Nanocomposite Photocatalysts for the Degradation of Methylene Blue.

Herein, Cellulose-templated Zn1-XCuXO/Ag2O nanocomposites were prepared using biological renewable cellulose extracted from water hyacinth (Eichhornia crassipes). Cellulose-templated Cu-doped ZnO catalysts with different amounts of Cu as the dopants (1, 2, 3, and 4%) were prepared and denoted CZ-1, CZ-2, CZ-3, and CZ-4, respectively, for simplicity. The prepared catalysts were tested for the degradation of methylene blue (MB), and 2% Cu-doped ZnO (CZ-2) showed the best catalytic performance (82%), while the pure ZnO, CZ-1, CZ-3, and CZ-4 catalysts exhibited MB dye degradation efficiencies of 54, 63, 65, and 60%, respectively. The best catalyst (CZ-2) was chosen to further improve the degradation efficiency. Different amounts of AgNO3 (10, 15, 30, and 45 mg) were used for the deposition of Ag2O on the surface of CZ-2 and denoted CZA-10, CZA-15, CZA-30, and CZA-45, respectively. Among the composite catalysts, CZA-15 showed remarkable degradation efficiency and degraded 94% of MB, while the CZA-10, CZA-30, and CZA-45 catalysts showed 90, 81, and 79% degradation efficiencies, respectively, under visible light within 100 min of irradiation. The enhanced catalytic performance could be due to the smaller particle size, the higher electron and hole separation and charge transfer efficiencies, and the lower agglomeration in the composite catalyst system. The results also demonstrated that the Cu-doped ZnO prepared with cellulose as a template, followed by the optimum amount of Ag2O deposition, could have promising applications in the degradation of organic pollutants.

Enhancing aquaculture management: Utilizing cu-doped ZnO/graphene nanocomposite for effective reduction of antibiotics and antibiotic-resistant Bacteria in shrimp culturing ponds

Shrimp culturing ponds, and enclosed breeding environments, contribute to the dissemination of antibiotics and antibiotic-resistant bacteria (ARBs) in aquatic ecosystems. This study focuses on the synthesis of a ternary nanocomposite photocatalyst, comprising Cu-doped ZnO and reduced graphene oxide (GP), using a one-step microwave-assisted hydrothermal method. The photocatalyst was employed to effectively eliminate antibiotics and inactive ARBs from aquaculture water. The structure, morphologies, and optical properties of the synthesized composites were investigated. Tetracycline (TET) and florfenicol (FLO) were the most frequently detected antibiotics in shrimp pond water, followed by sulfamethoxazole and tiamulin. Photo-degradation efficiency of TET and FLO using composite significantly improved under both UV and simulated solar irradiation. After 60 and 180 min of irradiation, the removal percentages for TET were 87.5% and 80.3%, while for FLO they were 89.5% and 92.1% respectively. The Cu-ZnO/GP composite demonstrates potent antibacterial activity against both Gram-positive (E. faecalis V583) and Gram-negative (E. coli K12 MG1655) antibiotic-resistant strains under light exposure. Its photocatalytic properties augment reactive oxygen species (ROS) generation, thereby enhancing bacterial inhibition. After 24 h of light exposure, E. coli growth was inhibited by 78%, while E. faecium growth was suppressed by 92%. The composite achieved the highest inactivation levels for E. coli (Ln-3.8) and E. faecalis (Ln-2.8) after 15 min of light exposure. The efficacy of Cu-ZnO/GP composite treatments in bacterial inactivation was notable in both ultrapure water (UPW) and real wastewater (RWW) matrices, achieving significant inactivation levels after a 1-h treatment. These findings underscore the potential of Cu-ZnO/GP composites to improve aquaculture management practices, thereby mitigating antibiotic proliferation in aquaculture waters and the surrounding environment.

Study of Electrical and Dielectric Behaviors of Copper-Doped Zinc Oxide Ceramic Prepared by Spark Plasma Sintering for Electronic Device Applications.

In this study, Cu-doped ZnO aerogel nanoparticles with a 4% copper concentration (Cu4ZO) were synthesized using a sol-gel method, followed by supercritical drying and heat treatment. The subsequent fabrication of Cu4ZO ceramics through Spark Plasma Sintering (SPS) was characterized by X-ray diffraction (XRD), field-emission gun scanning electron microscopy (FE-SEM) equipped with EDS, and impedance spectroscopy (IS) across a frequency range of 100 Hz to 1 MHz and temperatures from 270 K to 370 K. The SPS-Cu4ZO sample exhibited a hexagonal wurtzite structure with an average crystallite size of approximately 229 ± 10 nm, showcasing a compact structure with discernible pores. The EDS spectrum indicates the presence of the base elements zinc and oxygen with copper like the dopant element. Remarkably, the material displayed distinct electrical properties, featuring high activation energy values of about 0.269 ± 0.021 eV. Complex impedance spectroscopy revealed the impact of temperature on electrical relaxation phenomena, with the Nyquist plot indicating semicircular arc patterns associated with grain boundaries. As temperature increased, a noticeable reduction in the radius of these arcs occurred, coupled with a shift in their center points toward the axis center, suggesting a non-Debye-type relaxation mechanism. Dielectric analyses revealed a temperature-driven evolution of losses, emphasizing the material's conductivity impact. Non-Debye-type behavior, linked to ion diffusion, sheds light on charge storage dynamics. These insights advance potential applications in electronic devices and energy storage.

Synthesis and characterization of Cu-Doped ZnO nanostructures for UV sensing application

In this work, Fabrication, and characterization of Cu-doped ZnO thin films deposited on porous silicon (PSi) substrates have been reported using electrochemical deposition (ECD) technique. The influence of Cu-doping concentrations on morphology, structure, and electrical characteristics of zinc oxide (ZnO) thin films were presented. X-ray diffraction analysis (XRD) has been used to characterize the lattice constants, average size, in-plane (along a-axis) and out of plane (along c-axis) strains for the Cu–ZnO crystals. The effects of Cu-doping concentration on crystal parameters were also investigated from the XRD analysis. The samples were used for UV-sensing applications. In addition, Cu-doped ZnO and pure ZnO metal–semiconductor-metal photodetector, with Cu as electrode contacts were successfully produced for ultraviolet (UV) detection. The I-V (current–voltage) characteristics were used to study the sensing enhancement. Finally, the UV photodetector based on Cu-doped ZnO films was successfully fabricated and shows a five times enhancement in the sensitivity to UV light compared to that of pure ZnO photodetector.

Theoretical Study on the Structures and Stabilities of CunZn3O3 (n = 1–4) Clusters: Sequential Doping of Zn3O3 Cluster with Cu Atoms

Density functional theory (DFT) and coupled cluster theory (CCSD(T)) calculations are performed to investigate the geometric and electronic structures and chemical bonding of a series of Cu-doped zinc oxide clusters: CunZn3O3 (n = 1–4). The structural evolution of CunZn3O3 (n = 1–4) clusters may reveal the aggregation behavior of Cu atoms on the Zn3O3 cluster. The planar seven-membered ring of the CuZn3O3 cluster plays an important role in the structural evolution; that is, the Cu atom, Cu dimer (Cu2) and Cu trimer (Cu3) anchor on the CuZn3O3 cluster. Additionally, it is found that CunZn3O3 clusters become more stable as the Cu content (n) increases. Bader charge analysis points out that with the doping of Cu atoms, the reducibility of Cu aggregation (Cun−1) on the CuZn3O3 cluster increases. Combined with the d-band centers and the surface electrostatic potential (ESP), the reactivity and the possible reaction sites of CunZn3O3 (n = 1–4) clusters are also illustrated.

Enhanced photocatalytic degradation of pure and Cu-doped ZnO nanoparticles prepared under Co-precipitation method

The key goal of this study is to innovate the pure and 0.05, 0.10 and 0.15 wt.% of Cudoped ZnO NPs through co-precipitation technique. PXRD pattern shows the hexagonal crystal structure with no any phase impurity were observed for all the synthesized samples. From UV-Vis DRS spectra, band gap was obtained as 3.18, 3.24, 3.29 and 3.33 eV respectively for undoped, Cu-doped ZnO NPs (0.05, 0.10 and 0.15 wt.%). From SEM analysis, the agglomeration of rod-like morphology for pure ZnO NPs, spherical-like morphology for Cu-doped ZnO NPs (0.05 wt.%) and flake-like morphology for Cu-doped ZnO NPs (0.10 wt.%) and flower-like morphology for Cu-doped ZnO NPs (0.15 wt.%). The photocatalytic performance of the synthesized NPs was studied by the dye degradation of Methylene Blue (MB) under UV irradiation. The result exposed that, 0.15 wt.% of Cu-doped ZnO NPs is found to have efficient degradation candidate materials.

Origin of microscopically coupled ferromagnetic Cu-ions in a distorted system of Cu-doped ZnO and their synchrotron-based electronic structures

Spintronics-based studies have produced significant attention in the last decade while claiming the observation of room temperature ferromagnetism (RTFM). Nevertheless, there is a lack of consensus on a mechanism responsible for this phenomenon. In this study, we focus on Cu-doped ZnO (ZCO) to understand the microscopic origin of RTFM and the role of different oxidation states of Cu in RTFM. We have performed different spectroscopic techniques using synchrotron facilities. The values of spin-moment obtained from x-ray magnetic circular dichroism sum-rule truly exhibit a ferromagnetic interaction in the nanocrystalline powder of ZCO with ∼0.58 μB for 5% of Cu concentration in the total fluorescence yield mode. Such an enhanced magnetization is attributed to the presence of Cu2+, which is mainly localized in the bulk region. Cu in ZCO is mostly dominated by the presence of Cu2+. This is clearly reflected by the profiles of x-ray photoemission spectroscopy. Consequently, the weakly magnetized total electron yield mode is attributed to a state of magnetic frustration as the majority of Cu3+ is found on the surface. Some of these Cu3+ when come in the vicinity of Cu2+ ions result in a highly correlated state of double exchange mechanism, which is the microscopic origin of RTFM in ZCO. The coupling between Cu2+-Cu3+ is mediated via oxygen vacancies (VO), the presence of which is confirmed through the features of electron energy loss spectroscopy over different edges. The confirmation of VO is also supported by the deconvolution of E2high-phonon in the Raman spectra. Moreover, the defects in the local electronic structures of ZCO are demonstrated by the deconvoluted spectra of Cu L3 x-ray absorption spectroscopy. The images obtained from high-resolution transmission electron microscopy confirm the incorporation of Cu into the wurtzite crystal of ZnO. A clear enhancement in magnetization upon an increase in carriers of Cu in ZCO indicates carrier-induced ferromagnetism. Cu2+ and VO are the two attributes of RTFM in ZCO.

Investigation of the Doping and Withdrawal Speed Effect on the Properties of sol–gel Dip-coated Cu-Doped ZnO Thin Films

Investigation of the Doping and Withdrawal Speed Effect on the Properties of sol–gel Dip-coated Cu-Doped ZnO Thin Films

Synthesis of Bitter gourd-shaped Cu-doped ZnO nanostructures and their investigation for the detection of NO2 gas at low concentrations

Nitrogen dioxide (NO2) exposure can have several adverse health impacts on people, especially the respiratory system. Low selectivity, a lack of long-term stability, and structural and morphological optimization are some challenges associated with using ZnO for NO2 gas sensing. Therefore, we intended copper (Cu) doping in ZnO to alter its shape and gas-sensing characteristics. This study explores the synthesis, properties, and gas-sensing capabilities of bitter gourd-shaped Cu-doped zinc oxide (ZnO) nanostructures for the detection of nitrogen dioxide (NO2). A facile hydrothermal synthesis method was employed to synthesize bitter gourd-shaped Cu-doped ZnO nanostructures and comprehensively characterized by several techniques. Comprehensive characterizations of our produced Cu-doped ZnO nanomaterial demonstrated by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), and different energy spectrum. The material was annealed at 400 °C in a controlled dry air environment to improve its suitability for gas sensor applications. A series of temperature-ranging experiments were conducted to get gas-sensing readings from 25 °C to 300 °C. The resulting sensor, founded upon the distinctive morphology of Cu-doped ZnO structures reminiscent of the intricate shape of bitter gourd, unveiled good selectivity with a pronounced affinity for detecting NO2 gas. Notably, the zenith of its performance was attained at an operating temperature of 200 °C, where its selectivity and sensitivity were most pronounced. Even at a low concentration of 1 ppm, the sensors displayed a maximum response of 3.7, highlighting their high sensitivity. The sensors demonstrated excellent reproducibility, selectivity, and a low detection limit. These findings position bitter gourd-shaped Cu-doped ZnO nanostructures as promising candidates for NO2 sensing applications across diverse environments.

LED-enhanced photocatalytic reduction of hexavalent chromium by Cu-doped ZnO nanorods: kinetic modeling, cost analysis, and toxicity assessment

ABSTRACT This study unveils the synthesis and application of Cu-doped ZnO nanorods (NRS) as an efficient catalyst for the photocatalytic reduction of hazardous hexavalent chromium (Cr6+) in water. Synthesized via a simplified co-precipitation method, the NRS demonstrated enhanced performance, achieving an 89.35% Cr6+ reduction efficiency under optimal conditions. The catalyst’s performance was significantly augmented in the presence of hydrogen peroxide (H2O2) and revealed a first-order kinetic model. Radical trapping experiments highlighted the pivotal role of hydroxyl radicals in the photocatalytic process. A comparative analysis of the NRS with LED/ZnO and undoped ZnO underscores the superior efficiency of the Cu-doped variant. Moreover, the applicability of this system was validated in real water and wastewater matrices containing Cr6+, indicating its promising potential for industrial and environmental applications. An in vivo bioassay using Daphnia magna further confirmed the reduced toxicity post-treatment, underscoring the environmental friendliness of this innovative approach. The findings present Cu-doped ZnO nanorods as a promising, effective, and eco-friendly catalyst for the remediation of Cr6+ contaminated water, marking a significant stride towards sustainable and efficient water treatment solutions.

Physico-chemical and biological characterization of Ag- and Cu-doped ZnO thin films coated with calcium phosphates

Physico-chemical and biological characterization of Ag- and Cu-doped ZnO thin films coated with calcium phosphates

Rubia-inspired biogenic synthesis of Cu–ZnO nanocomposites: Dual-modelling of visible light photocatalytic degradation and antibacterial assessment

Cu-doped ZnO nanoparticles (NPs) were synthesised using Rubia cordifolia root extract and their photocatalytic degradation and antimicrobial properties were evaluated. Among all dopant concentrations, UV-VIS analysis of 5 % Cu–ZnO NPs revealed a clean shift towards the visible range with a reduction in the band gap from 3.2 eV for pristine ZnO to 2.98 eV. Formed NPs were identified as wurtzite crystal structure (size of 16.67 nm) having functional group of ZnO, using XRD and FTIR analysis. Highest photocatalytic degradation efficiencies of both Alizarine Red (AZ) (80 %) and Rhodamine B (RhB) (82 %) dyes were by 5 % Cu–ZnO NPs. Statistical modelling and optimization were conducted using Response Surface Methodology (RSM) and Adaptive Neuro-Fuzzy Inference System (ANFIS), resulting in development of models having >90 % predictive accuracy. Furthermore, the biogenic Cu–ZnO nanoparticles exhibits effective antimicrobial properties against both gram-positive (S. aureus) and gram-negative (E. coli) bacteria. The biogenic synthesis approach demonstrated enhanced photocatalytic efficiency and antimicrobial properties, suggesting its potential for environmentally friendly applications.

Structure, electrical and optical properties of ZnO and Cu-doped ZnO films prepared by magnetron sputtering at different H2 fluxes

Structure, electrical and optical properties of ZnO and Cu-doped ZnO films prepared by magnetron sputtering at different H2 fluxes

Enhanced Visible Light Photocatalytic Activity of Cu-Doped ZnO ALD Films Deposited on Porous Substrates

Enhanced Visible Light Photocatalytic Activity of Cu-Doped ZnO ALD Films Deposited on Porous Substrates

Therapeutic Physical Properties, Photocatalytic, and Anti-bacterial Activities of Hydrothermally Fabricated Cu-doped ZnO NPs

Therapeutic Physical Properties, Photocatalytic, and Anti-bacterial Activities of Hydrothermally Fabricated Cu-doped ZnO NPs

Visible Light Induced Photocatalytic Removal of Methylene Blue Using Cu-tunable p-type ZnO Nanoparticles.

Removal of phototoxicity and zootoxicity pollutants from the aqueous environment is of great importance to human and aquatic life. Copper-tunable p-type zinc oxide (Cu-ZnO) photocatalysts have been prepared by the chemical co-precipitation method. The structural, morphological, elemental and optical properties of the obtained catalysts were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis and ultraviolet-visible (UV-Vis) spectrophotometry. The diffraction patterns of the as-synthesized catalysts were matched with that of the hexagonal wurtzite structure for the standard ZnO nanoparticles. The photocatalytic activity of the prepared Cu-doped ZnO catalyst was evaluated using methylene blue (MB) dye under various conditions. The effect of operational parameters such as MB initial concentration, catalyst dosage, and solution pH was optimized using a face central composite design (FCCD) of the response surface methodology (RSM). The optimum photodegradation efficiency of 98.00% was found at 0.30g/L catalyst dose, 10.00mg/L initial concentration of MB and initial pH at 6.00. The degradation model was statistically remarkable with p < 0.0001% in which the MB initial concentration and solution pH were the most significant variables influencing the removal of MB over the Cu tunable p-type ZnO photocatalyst under visible light irradiation. Finally, the photocatalytic degradation of MB using the undoped and Cu-doped ZnO nanoparticles was nicely fitted pseudo-first-order kinetics scheme.