Monoclinic CuO Research Articles

SIMULATION STUDIES OF CR DOPED CUO HETEROJUNCTION SOLAR CELL

1% and 3% Cr doped CuO thin films have been deposited on soda lime glass by spin coating method and then their structural, morphological and optical properties have been investigated by operating X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Ultraviolet-Visible Spectroscopy (UV-Vis) techniques, respectively. XRD patterns of CuO:Cr (1%) and CuO:Cr (3%) thin films demonstrate characteristics of monoclinic CuO structure with a C2/c space group. The morphology of coated film plays an important role in analyzing some optoelectronic properties. 1% Cr doped CuO thin film absorbs more photons compared to 3% Cr doped CuO in Vis and UV regions. The band gaps of 1% Cr and 3% Cr doped CuO thin films are to be 2.18 eV and 2.30 eV, respectively. The Mo/1% and 3% Cr doped CuO/n-ZnO/i-ZnO/AZO solar cell has modelled with SCAPS-1D simulation program. The photovoltaic (PV) parameters of solar cell deteriorated with some increase in the neutral defect density (N_t) value. As the shallow acceptor defect density (N_a) value is increased, J_SC is decreased, V_OC, FF and η are increased. PV performance of 1% Cr doped CuO solar cell were found to be better than that of 3% Cr doped CuO solar cell. The efficiency of 1% Cr doped CuO solar cell is increased with the use of SnO2 intermediate layer in 2 nm thickness at the heterojunction interface.

Innovative approach to synthesize Mo-Doped CuO Nanostructures: Uncovering structural and photocatalytic insights

The synthesis of molybdenum-doped copper oxide was carried out using a sol–gel technique, with sodium hydroxide as a pH regulator. Structural, morphological, and compositional analysis of both pure and molybdenum-doped copper oxide was observed through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). For the monoclinic CuO nanostructure, key structural parameters like crystallite size, lattice parameters, micro strain, and dislocation density from XRD data was determined. Several methods, were employed to assess the crystallite size, micro strain, and dislocation density of synthesized nanostructures. The photocatalytic activity of Mo-doped CuO nano photocatalyst was evaluated using PL spectroscopy. Notably, the results demonstrated that 3% molybdenum-doped copper oxide removed 91% of the MB dye, outperforming the pure CuO sample, which only achieved 59% removal. This enhanced performance can be attributed to the increased surface area and optimized band gap of the Mo-doped CuO. The tuned band gap and unique nano architecture of the doped CuO not only facilitated the excitation process but also facilitated in transporting photo-induced species to the photo catalyst’s surface. These findings highlight the exceptional photocatalytic efficacy of the 3% molybdenum-doped CuO photo catalyst, showcasing its potential for treating toxic industrial effluents even through multiple cycles.

Growth and electrochemical properties of CuO nanowires-ZnO microrods composite

We have presented simple two step process to synthesize CuO nanowires - ZnO microrods composite using thermal oxidation and hydrothermal method respectively. The synthesized composite showed monoclinic CuO and hexagonal ZnO. Field emission scanning electron microscopy of the samples showed the randomly oriented CuO nanowires have average diameter ∼200 nm and length ∼10 μm. The ZnO microrods have diameter ∼1 μm and length ∼4 μm. The Raman spectrum of sample of CuO nanowires showed the peaks for Raman active (Ag + 2Bg) modes, while that of composite showed E1 and E2 modes of ZnO indicating lattice disorder and oxygen vacancy, along with Bg mode of CuO. Cyclic voltammetry in 0.1 M NaoH electrolyte of the samples showed pseudocapacitance nature of the material. At scan rate of 10 mV/s the CuO–ZnO composite showed specific capacitance of 57 F/g, while CuO nanowires showed ∼5 mF/g at 5 mV/s scan rate.

A Promising Electrochemical Sensor Platform for the Detection of Dopamine Using CuO‐NiO/rGO Composite

AbstractDopamine plays a significant role in the proper functioning of the central nervous system. Hence, the ability to sense levels of dopamine is pivotal in diagnosis and treatment procedures. For sensing dopamine, a mixed metal oxide nanocomposite (NC) of copper oxide‐nickel oxide/reduced graphene oxide (CuO‐NiO/rGO) is fabricated by the sol–gel method, and it is used to modify the glassy carbon electrode. The structural and morphological characterizations are done by X‐ray diffraction (XRD), Energy dispersive X‐ray (EDAX), Raman, and Scanning electron microscopy (SEM). XRD results exhibit monoclinic CuO, cubic NiO, and hexagonal rGO structures. The Raman studies confirm the D and G bands for rGO. Different electrochemical techniques are used to examine the efficacy of nanocomposite in detecting dopamine. The CuO‐NiO metal oxide NC response compared with the CuO‐NiO/rGO NC shows a better response by rGO containing nanocomposite.Further, the chronoamperometric method is employed, and the diffusion coefficient is calculated as 1.04 × 10−6 cm2 s−1. The differential pulse voltammetry is carried out to measure the nanocomposite's sensitivity and detection limit (LOD). The catalyst exhibits a sensitivity of 7.2 µA cm−2 mM−1 and a LOD of 0.006 µM. The composite can be used as a flexible skin patch sensor to predict abnormal dopamine levels such as Parkinson's disease.

UV filters and high refractive index materials based on carboxymethyl cellulose sodium and CuO@ZnO core/shell nanoparticles

Nanoparticles have substantially contributed to the field of skincare products with ultraviolet (UV) filters to preserve human skin from sun damage. Thus, the current study aims to develop new polymer nanocomposites for the efficient block of UV light that results from the stratospheric ozone layer loss. Co-precipitation method was used to successfully synthesis CuO@ZnO core/shell NPs with a well-crystalline monoclinic CuO core and wurzite ZnO shell. Using the casting method, core/shell NPs were successfully introduced to carboxymethyl cellulose sodium (CMC). The CMC nanocomposites displayed considerably broader optical response extending from near-ultraviolet to visible light, which was likely due to heterojunction between the p-CuO core and n-ZnO shell and defects originating from the synthetic process. The transmittance of pure CMC in the UV, visible, and near IR regions is significantly reduced with the addition of 2 and 4 wt% of CuO@ZnO core/shell NPs to CMC. 99% of UV light is absorbed when 4 wt% of CuO@ZnO core/shell NPs are added. The addition of different concentrations of CMC nanocomposite to one of the sunblock in Egyptian market were studied and showing the highest Sun Protection Factor of 22. Moreover, optical dispersion parameters and refractive index were improved strongly with core/shell NPs addition.

Evaluation of physiochemical and electrochemical behaviour of reduced grapheme functionalized copper nanostructure as an effective corrosion inhibitor

This study examines the physicochemical properties and corrosion resistance of hydrothermally produced copper oxide-reduced graphene oxide nanocomposite (CuO/rGO). The CuO/rGO nanocomposite has a well-defined and homogeneous structure, decreased crystal size, and uniformly distributed CuO nanoparticles tethered to the rGO. X-Ray diffraction confirms the fabrication of 15.1 nm crystalline monoclinic CuO nanoparticles. EDX confirms the composite's composition by detecting Cu, O, and C components. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (LSV) tests evaluate the CuO/rGO nanocomposite's corrosion resistance. A mild steel plate under an HCl electrolyte with corrosion in the PPM ratio treats the nanocomposite-coated substrate. The composite's synergistic effect is assessed by comparing its corrosion performance to CuO/rGO concentrations in ppm. The corrosion resistance data demonstrate that the CuO/rGO composite improves with inhibitor concentrations of 0, 25, 50, 75, and 100 ppm. Adding rGO to the composite protects it and speeds up charge transfer, reducing corrosion and improving stability. The composite's synergistic effect of CuO and rGO provides excellent corrosion resistance regardless of concentration, making it a viable material for corrosion-prone applications. The research develops novel and effective anti-corrosion methods to preserve materials in the food, automotive, and large-scale energy industries.
 KEY WORDS: CuO/rGO nanocomposite, Tafel plot, Corrosion protection, Surface analysis
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 269-280. DOI: https://dx.doi.org/10.4314/bcse.v38i1.20

Fabrication and physicochemical characterization of copper oxide–pyrrhotite nanocomposites for the cytotoxic effects on HepG2 cells and the mechanism

Abstract Novel CuO–FeS nanocomposites were synthesized to exert anticancer effects on HepG2 cells. The formation was initially demonstrated using UV–Visible spectrophotometry analysis, which indicated two peaks at 335 and 370 nm. Characteristic Fourier transform infrared spectroscopy peaks for Cu–O and Fe–S bonds were observed at 516, 577 and 619 cm−1 in addition to other notable peaks. The Miller indices correspond to the lattice spacing of monoclinic CuO and FeS as observed by selected area diffraction rings concurrent with the X-ray diffraction observations. The morphology was interpreted by scanning electron microscopy and transmission electron microscopy, indicating a particle size of 110 nm. As per energy-dispersive X-ray spectroscopy analysis, strong peaks for Cu (0.9, 8 and 9 keV), Fe (6–7 keV), O (0.5 keV) and S (2.5 keV) indicated the formation of CuO–FeS blend with no impurities. A mean particle size of 121.9 nm and polydispersity index of 0.150 were displayed by dynamic light scattering analysis and the zeta potential was −29.2 mV. The composites were not toxic to normal 3T3-L1 cells and were not haemolytic even at higher doses. In addition, the stable composites exerted cytotoxic effects on HepG2 cells (IC50 = 250 ± 5.7 μg/mL) and induced cell death by creating a loss in mitochondrial membrane potential and induction of mitochondrial apoptosis in a ROS-independent manner.

CuO/ZnO Type-II heterojunction modified by rGO nanosheets for improved photocatalytic mineralization of antibiotics

In the present work, CuO/ZnO type-II heterojunction was modified by graphene oxide nanosheets for excellent photocatalytic mineralization of antibiotics under artificial UV light and natural sunlight. For this purpose, CuO/ZnO heterojunction-graphene oxide nanocomposites were synthesized via a facile refluxing method in aqueous media. The synthesized nanocomposites were characterized through diverse characterization techniques such as XRD, FT- IR, Raman, SEM, TEM, and UV–Vis DRS to determine their structural, morphological, and optical properties. XRD analysis confirmed the monoclinic CuO and hexagonal wurtzite ZnO phase in bare CuO/ZnO heterojunction and different CuO/ZnO heterojunction-graphene oxide nanocomposites as well. The optical band gap was found in the range of 3.06–3.19 eV for different nanocomposites. The photocatalytic activity of the bare heterojunction and nanocomposites was performed against the degradation of ciprofloxacin under the irradiation of artificial UV and natural sunlight as well. The highest degradation % of ciprofloxacin was achieved at 96.27 % and 76.44 % under artificial UV and natural sunlight within 120 min, respectively over CuO/ZnO heterojunction with 3 wt% of graphene oxide. The outstanding photocatalytic performance of CuO/ZnO heterojunction-graphene oxide (3 wt%) owing to the high adsorption capacity and synergism between CuO/ZnO and graphene oxide caused the improved separation of charge species resulting higher production rate of reactive oxygen species and prompt degradation of ciprofloxacin.

Structural, optical, and dielectric properties of hydrothermally synthesized SnO2 nanoparticles, Cu/SnO2, and Fe/SnO2 nanocomposites

The structural and optical properties, as well as dielectric characteristics at various frequencies (0.1 Hz—20 MHz) and temperatures, T (300–400 K), of hydrothermally synthesized SnO2 nanoparticles, Cu/SnO2, and Fe/SnO2 composites have been investigated. The crystal structure is mostly formed of a tetragonal SnO2 phase, with a second phase of monoclinic CuO or rhombohedral Fe2O3 detected in Cu/SnO2, and Fe/SnO2 composites, respectively. The direct optical band gap, residual dielectric constant, and density of charge carriers are increased, while ac conductivity (σ ac) and dielectric constant decreased in Cu/SnO2 and Fe/SnO2. The value of σ ac was decreased while the electric Q-factor was increased by increasing T. SnO2 obeyed the hole-conduction mechanism for 400 ≥ T (K) ≥ 300, while Cu/SnO2 and Fe/SnO2 obeyed the electronic-conduction mechanism for 400 ≥ T (K) > 300. The binding energy is independent of T for SnO2, whereas it increases with rising T for Cu/SnO2 and Fe/SnO2 composites. F-factor and electronic polarizability are improved by a rise of T for SnO2 and Cu/SnO2 meanwhile are decreased for Fe/SnO2. The electrical impedance of the grains and their boundaries as well as equivalent capacitance are increased by increasing T and have higher values for Fe/SnO2 at T > 300 K. The obtained results recommend the synthesized Cu/SnO2 and Fe/SnO2 composites to be used as catalysts for water purification, anodes for lithium batteries, supercapacitors, and solar cell applications amongst others.

Enhanced electrochemical performance of CuO/NiO/rGO for oxygen evolution reaction

To design the highly active, stable electrocatalyst for oxygen evolution is emerging as challenging task for sustainable energy production. Herein, we fabricated the non-noble CuO/NiO/rGO nanocomposite approached by facile chemical co-precipitation method. The successful formation of binary metal oxide nanocomposite with reduced graphene oxide was confirmed with monoclinic CuO and cubic NiO, which is clearly revealed in the XRD diffraction results. By incorporating the CuO and NiO into the rGO sheets results homogeneous tiny nanoparticles morphology decorated on the graphene sheets which improving interaction among metal nanoparticles and carbon based products. The electrocatalytic performance of resultant binary metal oxide nanocomposite with rGO was investigated in alkaline KOH environment towards oxygen evolution reaction. The 200 mV overpotential was attained at 10 mA/cm2 with smaller 165 mV/dec Tafel value. The elevated electrochemical surface area (ECSA) value of 132.5 cm2 was estimated from cyclic voltammetry analysis of optimized CuO/NiO/rGO electrocatalyst. The electrochemical impedance spectrum of the prepared electrocatalyst shows that the low 0.04 Ω charge transfer resistance is highly desirable to the better conductivity. The prepared CuO/NiO/rGO electrocatalyst stability was verified by chronoamperometry test at low 10 mA/cm2 and exhibited stable performance up to 16 h towards OER. Hence, this work contributes innovative synergistic approach for growth of cost effective binary metal-oxide (CuO/NiO) nanocomposite combined with conductive carbon material for oxygen evolution reaction.

Preparation of CuO loaded cation exchange resin composites and its degradation of polyacrylamide aqueous solution

Macroporous cation exchange resins (CER) were used as carriers, and CuO loaded cation exchange resin composites was successfully prepared under thermostatic oscillation and hydrothermal conditions. The results showed that the as-prepared composites exhibited obvious shell-core structure. The different amounts of NaOH affected the micro morphology of CuO on the surface and in the internal pores of the resin, and also affected the percentage content of Cu element. XRD characterization clearly revealed that the products were monoclinic crystal system CuO species with a grain size of about 16 nm. The highest degradation rate of polyacrylamide (PAM) by CuO@IER-1g reached 81.94%, after 6 cycles CuO@CER-1g has still good photocatalytic activity, and the decrease in degradation rate was the combined effect from the adsorption of ion exchange resins and the electron-hole pairs formed by CuO and a series of free radical transfer reactions under ultraviolet light. This study has important theoretical basis and practical significance for enriching ion exchange theory, developing the photocatalytic industry, and purifying the environment.

Green synthesis of Ag/CuO and Ag/ [formula omitted] nanoparticles for enhanced photocatalytic dye degradation, antibacterial, and antifungal properties

In the context of synthesizing metal doped metal oxide nanoparticles (NPs), green synthesis emerges as a reliable, sustainable, environmentally-friendly, and exceptional alternative to the more efficient and conventional chemical methods. In this study, we explored the co-precipitation method performed for the Caesalpinia pulcherrima (C.pulcherrima) flower extract high percentage of hydroxyl functional groups on terpenoid derivatives, reducing and encapsulating agents, and the stability of the Ag/CuO and Ag/ TiO2 NPs. The XRD patterns provided evidence of the highly crystalline structure of monoclinic CuO, tetragonal crystal structure, and face-centered cubic Ag metal, obtained to improve the nanosized 6 and 8 nm, which structural defects in the synthesis materials were determined by scanning and transmission electron microscopy (SEM and TEM), as well as by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX) analyze. The existence of Ag ions (Ag+), Ti4+ ions, and Cu2+ ions in CuO and TiO2 caused the reduction of carbonyl and hydroxide functional groups, thereby facilitating the efficient formation of nanostructures, as demonstrated by XPS and Fourier transform infrared spectroscopy (FTIR). The band gap analysis of Ag/CuO and Ag/TiO2 NPs revealed that they increased the catalytic activity of methylene blue (MB) dye degradation efficiency achieved by 86 and 94 %, respectively. Comparatively, Ag doped with CuO and TiO2 has a synergistic effect leading to in highly effective antimicrobial activity against P. aeruginosa and E. coli infections.

Synthesis, characterization and enhancing efficiency of composite CuO2/CuO nanostructures deposited on porous activated carbon for supercapacitors electrode applications

The efficiency of supercapacitor (SC) electrodes made from hydrothermally obtained composite Cu2O/CuO nanostructures/activated Cassia fistula dry seed pod carbon (CCu NSs) was improved. X-ray results indicated a mixed phase of monoclinic CuO and cubic Cu2O nanoparticles. Morphology and dispersion of both phases were revealed using field emission scanning electron microscopy and transmission electron microscopy. Raman spectra indicated the characteristic peaks of disordered and graphitic carbon in all samples. Fourier transform infrared spectra confirmed the vibrational modes of Cu and O atoms. Specific surface area and pore-size distribution of samples were determined using a nitrogen adsorption-desorption isotherm. X-ray photoelectron spectroscopy was employed to examine their chemical surfaces. Electrochemical properties were evaluated with cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy with three-electrode and symmetric SC cell experiments in KOH. After a 5000 cycle GCD test at 5 A g−1, CCu-2 NS electrode demonstrated an exceptional EDLC performance with 91.2 % capacity retention and specific capacitance 277.80 F g−1 at 0.5 A g−1. Additionally, the fabricated CCu-2//CCu-2 NSs SC cell showed an outstanding 62.3 % capacity retention at 1 A g−1 after a 5000 cycle GCD test with high energy (Esd) and power densities (Psd) of 11.39 Wh kg−1 and 629.34 W kg−1, respectively.

Bi-metal-organic framework-derived S-scheme InP/CuO-C heterostructure for robust photocatalytic degradation of ciprofloxacin in a microfluidic photoreactor

The presence of antibiotics in the environment raises significant environmental concerns due to their adverse impact on organisms and the potential transmission of drug-resistant genes. Heterostructure photocatalysts have emerged as a promising remedy for this issue. This study introduces an innovative approach that employs an In/Cu-organic framework (bimetallic-MOF) as a sacrificial precursor for crafting a carbon-supported InP/CuO heterostructure with adjustable band-matching properties. Through comprehensive analyses encompassing structural, morphological, optical, electrochemical, and density functional theory calculations, compelling evidence is presented for the cubic carbon layer housing zinc-blende InP and monoclinic CuO. Furthermore, the existence of an S-scheme charges transfer pathway between InP and CuO is strongly substantiated, significantly enhancing spatial charge separation. The engineered InP/CuO S-scheme nanoheterostructure exhibits exceptional performance and stability under visible light exposure within a custom-designed spiral microfluidic photoreactor (SMPR), achieving an impressive 81.70% degradation of ciprofloxacin – a commonly found antibiotic in wastewater – in just 15 min. The findings from photoelectrochemical and spectroscopic analyses reveal that the InP/CuO S-scheme heterostructure, derived from the bi-MOF, in conjunction with the SMPR, not only exhibits a robust response to visible light, improved carrier mobility, and effective charge separation and transfer, but also enhances mass and photon transfer. Within the S-scheme heterostructure, the process of charge transfer centers on the creation of reactive oxygen species, specifically OH and O2–, on InP and CuO surfaces, correspondingly. These species function as oxidation and reduction photocatalysts, respectively, exerting a pivotal influence in augmenting the overall performance. The findings make substantial contributions towards creating effective and sustainable solutions for mitigating environmental contamination, emphasizing the crucial role of advanced material design and microfluidic reactor engineering in the realm of photocatalysis.

Facile dip-coating assisted preparation of reduced graphene oxide-copper oxide nanocomposite thin films on aluminum substrate for solar selective absorber

Reduced graphene oxide integrated copper oxide nanocomposite thin film (rGO-CuO NC TF) solar selective absorber coatings were devised on aluminum substrate using dip-coating procedure. The prepared coatings were subjected to characterization by scanning electron microscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, PL spectroscopy, UV–vis–NIR spectrophotometer, Emissometer and Raman spectroscopy. XRD and Raman analyses disclosed presence of mono-phase with highly crystalline monoclinic structured CuO in the rGO-CuO NC TFs. The SEM images revealed grain-like morphology of CuO, which are randomly distributed on rGO sheets. EDX and XPS investigations confirmed presence of anticipated chemical constituents and chemical composition, respectively in the NC TFs. The rGO-CuO NC TF with 1.0 wt% GO disclosed absorptance (α) of 79.92% and emittance (ε) of 4.2% with a highest selectivity (ξ) of 19.03 that suggests its promising prospect for solar absorber coating in solar thermal devices.

Incorporation of copper in LaCoO3: modulating thermoelectric power factor for low- and mid-temperature thermoelectric applications

In the present work, LaCoO3/ x wt% Cu (x = 0%, 5%, 10%, 15%, and 20%) samples were prepared using solid-state reaction method followed by conventional sintering. We have performed electrical and thermoelectric (TE) measurements on these samples both at low (100–310 K) as well as in mid (310–790 K) temperature range. X-ray diffraction (XRD) studies showed that the pristine LaCoO3 sample crystallized in a distorted rhombohedral structure with the space group Rstackrel{-}{3}c. Interestingly, the addition of Cu resulted in two distinct phases viz. rhombohedral LaCoO3 and monoclinic CuO. Throughout the entire temperature range, the electrical resistivity of the samples decreased with temperature, which depicts the semiconducting behavior of the prepared samples. Furthermore, there is a crossover from negative to positive Seebeck coefficient for the pristine sample at 275 K, but all the copper-incorporated samples exhibited a positive Seebeck coefficient indicating holes as the majority charge carriers. It is found that, the sample with x = 10% exhibited the maximum power factor of about 99 µW/m K2 at 400 K, which is significantly higher than the pristine sample at the same temperature.

Waste remediation: Low-temperature synthesis of hybrid Cu(OH)2/CuO and CuO nanostructures from spent printed circuit boards and their dye degradation studies.

The demand for environmentally friendly and sustainable resource utilization techniques for recycling waste printed circuit boards is significant due to their status as valuable secondary resources, containing high-purity copper and precious metals. In this context, Cu(OH)2/CuO and CuO nanostructures were fabricated using alkaline precipitation and low-temperature aging methods using the strip solution originated from laboratory-scale spent mobile phone printed circuit board recovery process. XRD, FTIR, FESEM-EDX, and TEM were utilized to characterize the as-recovered nanoproducts. A hybrid structure of Cu(OH)2/CuO was formed at 70°, and monoclinic CuO phase was formed at 80°C aging time. The results show that Cu(OH)2/CuO nanoflakes have an average crystallite size of 24.06nm and a particle width of 22 ± 3nm. Cu(OH)2/CuO nanoflakes formed at 70°C aging temperature and 24-h residence time have finer crystallite and particle sizes than CuO-ridged nanospheres formed at 80°C aging temperature. The optical band gap energy of Cu(OH)2/CuO and CuO nanostructures formed was found to be 2.28eV and 2.22eV, respectively. The hybrid Cu(OH)2/CuO nanostructure photocatalyzed the decomposed 97.28% rhodamine blue using a visible light source, whereas the CuO nanostructure degraded only 14.64% rhodamine blue dye under similar conditions. A surfactant-less hybrid structure is developed without the use of any chemical precursor. Thus, a high value-added product is produced using one waste material to remove another waste in wastewater treatment.

Waste to wastewater treatment: Synthesis of CuO nanoparticles from discarded printed circuit boards for the removal of Methylene Blue under visible light

Owing to the swift advancements in the electronic industry and the increased demand, electronic equipment has a reduced lifespan in both developed and developing country markets, causing the generation of tons of electronic waste. The improper disposal of discarded Printed Circuit Boards (PCBs) can pose various environmental risks, despite the fact that they are a valuable source of high-purity copper and precious materials. Consequently, there is a significant demand for the recycling of waste PCBs using environmentally friendly and appropriate sustainable resource utilization methods. In this study the metallic clads separated from downsized PCBs are leached into the solution phase and precipitation with an alkaline medium is done to recover Copper Oxide nanoparticles (CuO NPs). The XRD analysis provided confirmation that the synthesized nanoparticles were monoclinic CuO, free from any impurities. FTIR confirmed that the synthesized product is pure CuO. The surface morphology of the synthesized CuO was revealed through FESEM, which showed irregular morphology. Further confirmation of this was obtained through TEM analysis. Additionally, the direct band gap was measured to be 1.93 eV. The as-synthesized nanoparticles are utilized for the degradation of Methylene Blue when exposed to visible light. Hence e-waste can be useful to produce value-added product to solve environmental problem as well as reducing the problematic e-waste, preserving naturally occurring ores.

Analysis and characterization of structural, morphological, thermal properties and colloidal stability of CuO nanoparticles for various natural fuels

CuO nanoparticles were made quickly from natural macromolecules using the combustion process, and their structural, morphological, thermal, and particle stability properties were examined. All samples were monoclinic polycrystalline by XRD. Tea extract, wine, honey, and cow urine-assisted nanoparticles had crystallite sizes of 25.82, 26.18, 27.69, and 25.32 nm, respectively, according to the WH plot. FESEM and EDAX analysis verifies leaf, pollen grain, disc, and rice-like morphologies and stoichiometric products. Crystallite size correlates with TEM mean particle size. The parameters of the XRD pattern, which was matched with the standard data, reveal the presence of a pure monoclinic CuO phase with only substantial vibrations at 430 cm-1 to 603 cm-1. Thermal investigations (TG-DTA) demonstrate that particles are stable at 896°C-960°C before sublimating. Tea extract, wine, honey, and cow urine have been shown to affect CuO weight reduction. Anti-microbial study of the organic fueled CuO was made with Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacteria, also Candida albicans and Aspergillus niger fungi. It is found that CuO nanoparticles effectively inhibit fungal growth more than bacterial growth.

Highly photoactive rGO-MnO2/CuO nanocomposite photocatalyst for the removal of metanil yellow dye and bacterial resistance against Pseudomonas Aeruginosa

The superior photocatalytic, biological, and electrochemical properties of metal oxide nanocomposites have made them an important part of contemporary nanotechnology research. Nanocomposite involving MnO2 and CuO has been widely utilized for catalytic and electrochemical applications. However, the different oxidation states of MnO2 and lower band gap of CuO limits the efficiency of the devices involving the composite of these two semiconductors. As a result, reduced graphene oxide (rGO) is integrated into the MnO2/CuO matrix. rGO-MnO2/CuO and MnO2/CuO nanocomposites (NCs) were synthesized using one-pot green synthesis and chemical precipitation respectively. rGO decorated MnO2/CuO NC was green synthesized from graphene oxide using Alternanthera sessilis leaf extract. XRD detected peaks related to orthorhombic structured MnO2 and monoclinic structured CuO for both the composites. Star shaped nanostructures are observed for rGO incorporated MnO2/CuO nanocomposite. MC and rMC composites have band gaps of 2.16 and 2.04 eV, respectively. FTIR spectrum showed the characteristic peaks for MnO2 and CuO in the rGO-MnO2/ CuO composite. Raman active Ag and Bg CuO modes occur at 270 and 450 cm−1 and Mn-O symmetric vibrations at 590 and 540 cm−1. The incorporation of rGO into the MnO2/CuO composite increased its photocatalytic activity from 87 % to 96 % against the degradation of metanil yellow dye by increasing its electron conductivity, adsorption capacity, and light absorption capacity. The MnO2/CuO nanocomposite with rGO demonstrated enhanced antibacterial activity, with a zone of inhibition of 24 mm compared to 13 mm for the control and 18 mm for the MnO2/CuO composite.