China
Africa
Explore chapters and articles related to this topic
MOFs Metal Oxide-based Nanocomposites
Published in Ram K. Gupta, Tahir Rasheed, Tuan Anh Nguyen, Muhammad Bilal, Metal-Organic Frameworks-Based Hybrid Materials for Environmental Sensing and Monitoring, 2022
M. Irfan Hussain, Ghulam Abbas Ashraf, Muhammad U. Farooq, Muhammad Siddique Ahmad, Jazib Ali, Muhammad Usman Khan
CuO is semiconducting and attracted particular attention, owing to the versatility of the monoclinic structure. It is covalent in characteristics with an average small size for synthesis with wet-chemical techniques. Cuprous oxide (Cu2O), a reddish material with a coordinated oxygen atom, and cupric oxide (CuO) or copper (II) oxide, a black material, are the two common copper oxides. It possesses p-type semiconductors and is a significant product of copper mining with a bulk direct Eg of 2-2.17 eV. Both cooper oxides have fine/narrow Eg of 1.2 eV (bulk) for CuO, which is extracted from solids. As the heat treatment causes negatively charged vacancies, commonly attributed to the p-type character of both oxides [34]. At normal temperature, Cu2O has good conduction about 100 cm2 V-1s-1, resulting in an exceptional expansion with different micrometer ranges. Cu2O excitons have been discovered with high stability as (10 µs) after photoexcitation.
Remediation of Organic Pollutants Using Biobased Nanomaterials
Published in Narendra Kumar, Vertika Shukla, Persistent Organic Pollutants in the Environment, 2021
Solomon E. Shaibu, Edu J. Inam, Eno A. Moses, Nsikak A. Abraham, Nnanake-Abasi O. Offiong
The suitability of a nanoremediant is also dependent on the target organic micropollutants. Again, Sahithya et al. (2016) established this by comparing the adsorptive removal efficiencies against the organophosphate insecticide monocrotophos of nanocomposites of montmorillonite, copper(II) oxide, and chitosan; montmorillonite, copper(II) oxide, and polylactic acid; and montmorillonite, copper(II) oxide, and gum ghatti. The nanocomposite derived from polylactic acid performed better than the chitosan-based material. Further analysis revealed major involvement of amines and carboxylic groups, carbon atoms, copper(II) oxide nanoparticles, and silicon in the process. The homogeneity of the composite derived from polylactic acid was said to account for its superior efficiency during monocrotophos removal from aqueous matrix.
Synthesis of Solids
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
High-temperature superconductors (see Chapter 10) were first prepared using a conventional ceramic method. For example YBa2Cu3O7−x. (Figure 3.4) can be synthesised by baking together yttrium oxide, copper(II) oxide, and barium carbonate. The synthesis, however, takes 24 hours to complete. A microwave method that can prepare the superconductor in under 2 hours has been reported. A stoichiometric mixture of copper(II) oxide (CuO), barium nitrate (Ba(NO3)2), and yttrium oxide (Y2O3) was placed in a microwave oven that had been modified to allow safe removal of the nitrogen oxides formed during the reaction. The mixture was treated with 500 W of microwave radiation for 5 minutes, then reground and exposed to microwave radiation at 130–500 W for 15 minutes. Finally, the mixture was ground again and exposed to microwave radiation for a further 25 minutes. The microwaves in this example couple to the copper(II) oxide.
Laser-Assisted coating techniques and surface modifications: a short review
Published in Particulate Science and Technology, 2021
Behzad Fotovvati, Amir Dehghanghadikolaei, Navid Namdari
Using the laser-assisted direct material deposition method, Mansour et al. (Mansur, Wang, and Berndt 2013) developed a composite coating of hydroxyapatite (HA) and Ti-6Al-4V, which had two distinct layers including a top hard ceramic layer on a heat-affected zone, in which Ti diffuses into Fe. They found that a combination of the laser power and traverse speed, i.e., energy density, controls important coating features such as mechanical properties, microstructure, and chemistry. With the energy density of 167 J/mm2, they could obtain a Ca/P ratio of less than 1.67 (nearest to human bone), which is favorable for cell apoptosis and clinical practice. Rytlewski (Rytlewski 2014) compared two different coating compositions of 5 wt.% of Cu(acac)2 and 15 wt.% of copper(II) oxide (CuO) or copper(II) hydroxide (Cu(OH)2). They used various numbers of laser pulses at a constant fluence of 100 mJ/cm2 to irradiate the coatings followed by electroless metalization with copper. More efficient laser ablation and formation of metallic copper on the coating surface containing CuO allowed the copper to be plated at a higher energy dose of laser radiation compared to the coatings containing Cu(OH)2. The authors observed less porosity in the coating containing CuO rather than in Cu(OH)2, and they attributed this observation to the formation of water, which results in the thermal decomposition of Cu(OH)2.
Enhancement of dielectric and electro-optical parameters of a newly prepared ferroelectric liquid crystal mixture by dispersing nano-sized copper oxide
Published in Liquid Crystals, 2020
Sidra Khan, Shikha Chauhan, Achu Chandran, Michał Czerwiński, Jakub Herman, Ashok M. Biradar, Jai Prakash
As can be seen from the figure, the dielectric permittivity of the nCuO/FLC composite (0.25 wt% and 0.5 wt%) is increased upto ~50 at 20 Hz comparing to the permittivity value (~35) of pristine FLC material W302. It is reported that copper (II) oxide shows enhanced dielectric properties [61,62]. The enhancement in the dielectric permittivity is due to the effective coupling of FLC molecules with dielectric nCuO. The low-frequency peak due to p-UHM process disappears by doping nCuO into FLC material W302 owing to the effect of nCuO on the dynamics of the FLC molecules at the interface of FLC and the solid substrate of the sample cell, as seen in Figure 6(b). The low-frequency peak comes in highly anchored surfaces due to the partial unwinding of the helical structure near the surface of the substrates. In weakly anchored surfaces, the p-UHM process is not dominant. The unwinding mode can be suppressed either by decreasing the surface anchoring at the surface of the substrate or by increasing surface tension of FLC materials by doping suitable nanomaterials in the host FLC materials [41]. The effects of doped NPs of CuO on thermal stability of the nCuO/FLC composite are very important, but the results based on the effect of nCuO doping on thermal stability are under investigation and will be reported elsewhere in near future.
A new route for the synthesis of functionalized benzothiadiazine 1,1-dioxide derivatives via intramolecular C–H activation reactions of N,N′,N′′-trisubstituted guanidines and benzenesulfonylchloride
Published in Journal of Sulfur Chemistry, 2018
Maryam Nazari, Manijeh Nematpour, Elham Rezaee, Mehdi Jahani, Sayyed Abbas Tabatabai
Initially, we examined various copper catalysts, including copper (I) bromide, copper (I) iodide, copper (II) sulfate, copper (II) acetate, and copper (II) oxide, for the synthesis of N,N′,N′′-trisubstituted guanidines from aniline and carbodiimides. Only the copper (II) oxide gave the best results. We therefore optimized the reaction conditions for hydroamination of carbodiimides by using copper (II) oxide as a catalyst for the model reaction of aniline (2a) with N,N′-dicyclohexylcarbodiimide (1a; DCC). A brief screening of solvents including acetonitrile, toluene, THF and DMF in the presence of 10 mol% of catalyst under reflux showed that acetonitrile was found as the best solvent for this reaction (Table 1).