Crystal structure prediction and property calculation of copper-oxygen compounds using innovative search software from first principles

A Bayesian optimisation algorithm for deep learning crystal structure prediction software (CBD-GM) is used to predict the structures of Cu(I) and Cu(II) oxides of 2D and 3D materials. Two known 2D structures and two known 3D structures were anticipated, in addition to the prediction of 5 novel structures. All nine structures were optimised and analysed using density-functional theory (DFT). Firstly, DFT calculations using the PBE functional indicate that the structures should be thermodynamically and dynamically stable. Secondly, we calculated the elastic constants using the "stress-strain" method, and the predicted Young's modulus and Poisson's ratios of the materials suggest that they all should have excellent ductile mechanical properties. Calculations of the band structure of the materials performed using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional indicate that some of the materials should be semiconductors with useful bandgaps. The results therefore provide inspiration for the synthesis of new copper oxides for industrial applications.

Glycerol Valorization Towards Glycolic Acid Production Over Cu-Based Biochar Catalyst

Glycerol valorization towards high-value chemicals is of particular importance to increase the value chain of biodiesel production. In this study, the catalytic activity of a series of cheap Cu-based catalysts for glycerol conversion is investigated. Cu supported on activated carbon (AC, obtained through carbonization of coconut shell) exhibits outstanding catalytic activity for the selective conversion of glycerol into glycolic acid (GcA) in O₂ atmosphere, affording up to 68.3 % GcA yield. The combination of experimental results with theoretical calculations reveals that glyceraldehyde is the key reaction intermediate. The high specific surface area and surface oxygenated groups of AC enable the formation of CuO nanoparticles with small size and uniform dispersion. In addition, the surface oxygen vacancy on Cu/AC might help to activate reaction intermediates, and the electron transfer from Cu to AC facilitates the oxidation of glycerol to GcA. Cu loaded onto AC also significantly inhibits C-C breakage to generate formic acid as a byproduct. This work might aid the development of approaches for glycerol application and afford profitable possibilities for sustainable biodiesel.

Gum mediated synthesis and characterization of CuO nanoparticles towards infectious disease-causing antimicrobial resistance microbial pathogens

BACKGROUND

In this work biologically active CuO nanoparticle were discussed. The literature suggests that CuO shows very good antibacterial activity on both Gram positive and Gram-negative bacterial strains. Further, it is used in antibacterial coatings on various substrates to prevent various kinds of medical equipment's. Here CuO NPs was prepared via greener approach and almond gum is used as a reducing agent. Almond gum is nontoxic and contains huge amount of polysaccharides. Hence, the gum mediated CuO NPs can be used to treat urinary tract infection (UTI).

METHOD

The CuO NPs were characterized using UV, FTIR, XRD and HESEM with EDX analysis. The antibacterial (both Gram positive and Gram negative) effects of CuO NPs were determined with agar well diffusion method.

RESULTS

The CuO NPs were characterized by X-ray diffraction pattern result indicates that the monoclinic structure with average crystallite size about 12.91 nm. Straight line model in Scherrer method results found to be crystallite size. The crystallite size and microstrain were estimated in W-H analysis. Lorentz polarization factor, size-strain plot (SSP), morphological index (M-I) and dislocation density were calculated based on x-ray diffraction data. The FTIR analysis confirms presence of Cu and O band. From the absorption spectrum of CuO NPs, it was found to be cutoff wavelength of 230 nm and direct bandgap was found to be 4.97 eV. Morphology analysis shows that the synthesized of CuO NPs reveals agglomerated and spherical in shape. It was found to be 16 nm-25 nm. Energy dispersive spectroscopy (EDX) result indicates percentages of Cu and O element present in the sample. Antimicrobial studies reveal zone of inhibition of CuO NPs. This was used in different pathogens such as gram-positive and Gram-negative bacteria. This study shows exhibit excellent antimicrobial effects of CuO NPs.

CONCLUSION

Hence, in this article the novel and cost-effective method to prepare CuO NPs was discussed. The prepared CuO NPs can be used as an antifungal and antibacterial reagent.

Green synthesis of multifunctional carbon coated copper oxide nanosheets and their photocatalytic and antibacterial activities

The studies of metal oxides in environmental remediation of chemical and biological pollutants are gaining colossal importance. Herein, we report the facile synthesis of multifunctional copper oxide nanosheets (CuO NS) using an aqueous extract of Rhazya stricta. The phytochemical investigation of R. stricta indicated the presence of saponins, tannins, and reducing sugars, responsible for the reduction and stabilization of CuO NS. A UV–Visible spectrophotometer initially confirmed the fabrication of CuO NS with specific Surface Plasmon Resonance at 294 nm. Field Emission Scanning Electron Microscopy (FE-SEM), Fourier-transform infrared spectroscopy FTIR, and XRD were further used to characterize the CuO NS. The obtained CuO NS were poly-dispersed with an average size of 20 nm. Interestingly these particles were aligned together in 3D cubical sheets layered above each other via self-assembly. The as-synthesized CuO NS showed enhanced antibacterial potential (17.63 mm, overall mean inhibition zone) in comparison to the known antibiotics (11.51 mm, overall mean inhibition zone) against both Solanaceous crop's wilt-causing bacteria (Ralstonia solanacearum and Clavibacter michiganensis). Furthermore, the appreciable photocatalytic potential of CuO NS has also been observed, causing 83% degradation of methylene blue (MB) upon solar irradiation. The synthesis methodology is devoid of any toxic waste or by-products. It could be used to produce eco-friendly CuO nanomaterial for industrial uses.

Titanium Dioxide (TiO2) Mesocrystals: Synthesis, Growth Mechanisms and Photocatalytic Properties

Hierarchical TiO2 superstructures with desired architectures and intriguing physico-chemical properties are considered to be one of the most promising candidates for solving the serious issues related to global energy exhaustion as well as environmental deterioration via the well-known photocatalytic process. In particular, TiO2 mesocrystals, which are built from TiO2 nanocrystal building blocks in the same crystallographical orientation, have attracted intensive research interest in the area of photocatalysis owing to their distinctive structural properties such as high crystallinity, high specific surface area, and single-crystal-like nature. The deeper understanding of TiO2 mesocrystals-based photocatalysis is beneficial for developing new types of photocatalytic materials with multiple functionalities. In this paper, a comprehensive review of the recent advances toward fabricating and modifying TiO2 mesocrystals is provided, with special focus on the underlying mesocrystallization mechanism and controlling rules. The potential applications of as-synthesized TiO2 mesocrystals in photocatalysis are then discussed to shed light on the structure–performance relationships, thus guiding the development of highly efficient TiO2 mesocrystal-based photocatalysts for certain applications. Finally, the prospects of future research on TiO2 mesocrystals in photocatalysis are briefly highlighted.

Synthesis of high melting point TiN mesocrystal powders by a metastable state strategy

Synthesis of high melting point non-oxide ceramic powders with mesocrystal structure is an important and challenging task.

Real-Time and Tunable Substrate for Surface Enhanced Raman Spectroscopy by Synthesis of Copper Oxide Nanoparticles via Electrolysis

Here we show the capability of copper oxide (CuO) nanoparticles formed on copper (Cu) electrodes by the electrolysis as a real time active substrate for surface enhanced Raman scattering (SERS). We have experimentally found that using just the ultra pure water as the electrolyte and the Cu electrodes, ions are extracted from the copper anode form copper oxide nanoparticles on the anode surface in matter of minutes. Average particle size on the anode reaches to 100 nm in ninety seconds and grows to about 300 nm in five minutes. This anode is used in Raman experiments in real time as the nanoparticles were forming and the maximum enhancement factor (EF) of Raman signals were over five orders of magnitude. Other metal electrodes made of brass, zinc (Zn), silver (Ag) and aluminum (Al) were also tried for the anode material for a possible real-time substrate for SERS applications. Experimentally obtained enhancement factors were above five orders of magnitude for brass electrodes like the copper but for the other metals no enhancement is observed. Electron microscope images show the cubic nanoparticle formation on copper and brass electrodes but none in the other metals studied.

Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature

Copper nanoparticles have been deposited on silicon surfaces by a simple galvanic displacement reaction, and rapid thermal annealing has been performed under various atmospheric conditions. In spite of the general tendency of the agglomeration of nanoparticles to lower the surface energy at elevated temperatures, our plan-view and cross-sectional transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis shows that the thermal oxidation of the copper nanoparticles and formation of cupric oxide (CuO) on silicon surfaces leads to wetting rather than agglomeration. In contrast, agglomeration has been observed when copper nanoparticles were annealed in a nitrogen environment. The lattice transformation from cubic Cu to monoclinic CuO, and hence the change in surface energy of the particles, assists the wetting process. The occurrence of wetting during the oxidation step implies a strong interaction between the oxidized film and the silicon surface.

Hollow CuxO (x = 2, 1) micro/nanostructures: synthesis, fundamental properties and applications

In this review, we comprehensively summarize the important advances in hollow Cu_xO micro/nanostructures, including the universal synthesis strategies, the interfacial Cu–O atomic structures as well as the intrinsic properties, and potential applications. Remarks on emerging issues and promising research directions are also discussed.

Shape-controlled synthesis of Sn-doped CuO nanoparticles for catalytic degradation of Rhodamine B

The uniform Sn-doped CuO nanoparticles were synthesized by a simple solution method at a low temperature. The prepared samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy techniques (HRSEM, HRTEM, SAED, STEM and EDS elemental mapping), atomic force microscopy (AFM), UV/Vis spectroscopy, nitrogen physisorption (BET) and by evaluation of the catalytic activity on the degradation of Rhodamine B. The tin doping had a considerable influence on the morphology of CuO. The gradual narrowing of the particles morphology in the crystallographic [010] direction was observed with increasing the dopant concentration. The plate-like, rectangularsquare and rod-like CuO nanoparticles were obtained. The mechanism of a crystal growth of CuO associated with doping is proposed. The tin doping also affected the structural and optical properties of CuO. Increasing the amount of a dopant led to a red-shift of a band gap from 1.33 to 1.18eV. The incorporation of tin into the structure of copper oxide was confirmed by XRD and distribution of tin mapped by EDS analysis. The good catalytic properties of the as-prepared doped material were demonstrated by the enhanced catalytic removal of Rhodamine B in the presence of H2O2. The undoped CuO nanosheets reached only 24% efficiency in the removal of Rhodamine B within two hours. The best result exhibited CuO_050Sn sample containing 4at.% of tin and the degradation of Rhodamine B reached 99% within the same time. We have demonstrated a simple, scalable process for the preparation of catalytically very active Sn-doped CuO nanoparticles with varying properties.

Facile synthesis of 2D CuO nanoleaves for the catalytic elimination of hazardous and toxic dyes from aqueous phase: a sustainable approach

This article reports for the first time a facile, green synthesis of 2D CuO nanoleaves (NLs) using the amino acid, namely aspartic acid, and NaOH by a microwave heating method. The amino acid acts as a complexing/capping agent in the synthesis of CuO NLs. This method resulted in the formation of self-assembled 2D CuO NLs with an average length and width of ~300-400 and ~50-82 nm, respectively. The as-synthesized 2D CuO NLs were built up from the primary CuO nanoparticles by oriented attachment growth mechanism. The CuO NLs were characterized by an X-ray diffraction (XRD) method, transmission electron microscopy (TEM), selected-area electron diffraction (SAED) pattern, and Fourier transform infrared spectroscopy (FT-IR). The optical properties were investigated using UV-visible spectroscopy. For the first time, rose bengal and eosin Y dyes were degraded photochemically by solar irradiation using CuO NLs as a photocatalyst. The synthesized CuO NLs act as an efficient photocatalyst in the degradation of rose bengal and eosin Y dye under direct sunlight. The degradation of both the dyes, namely rose bengal and eosin Y, took place within 120 and 45 min, respectively, using CuO NLs as a photocatalyst, whereas commercial CuO, SnO2 quantum dots (QDs), and commercial SnO2 took more than 120 and 45 min for the degradation of rose bengal and eosin Y, respectively. The synthesized CuO NLs showed a superior photocatalytic activity as compared to that of commercial CuO, SnO2 QDs, and commercial SnO2. The reusability of the CuO NLs as a photocatalyst in the degradation of dyes was investigated, and it was evident that the catalytic efficiency decreases to a small extent (5-6 %) after the fifth cycle of operation.

Bundle-like α'-NaV2O5 mesocrystals: from synthesis, growth mechanism to analysis of Na-ion intercalation/deintercalation abilities

Bundle-like α'-NaV2O5 mesocrystals were synthesized successfully by a two-step hydrothermal method. Observations using electron microscopy revealed that the obtained NaV2O5 mesocrystals were composed of nanobelts with the preferential growth direction of [010]. The precise crystal structure was further confirmed by Rietveld refinement and Raman spectroscopy. Based on analysis of crystal structure and microscopy, a reaction and growth mechanism, hydrolysis-condensation (oxolation and olation)-ion exchange-self-assembly, was proposed and described in detail. Furthermore, electrochemical measurements were used to analyze the Na-ions intercalation/deintercalation abilities in NaV2O5, and indicated that Na-ions were difficult to extract. Importantly, the DFT theoretical calculation results, which showed that the migration energy of Na-ions was so huge that migration of Na-ions was quite difficult, can explain and support well the results of the electrochemical measurements.

Facile fabrication of three-dimensional hierarchical CuO nanostructures with enhanced lithium storage capability

3D hierarchical CuO nanostructures with flower-like and urchin-like morphologies have been prepared by a solvothermal method. They display high discharge capacity, good rate capability and long cycle life as anode materials for lithium-ion battery.

Synthesis of high aspect ratio CuO submicron rods through oriented attachment and their application in lithium-ion batteries

High aspect ratio CuO submicron rods were synthesized via the polymer-assisted oriented attachment of nanocrystal building blocks along with calcination.

Synthesis of high-purity CuO nanoleaves and analysis of their ethanol gas sensing properties

High purity CuO nanoleaves synthesized in solution through oriented attachment exhibit good gas sensing behavior with ethanol.

Selective growth of metallic nanostructures on microstructured copper substrate in solution

Two kinds of micro/nanostructured superhydrophobic CuO surfaces were achieved by the solution-immersion method.

Shape evolution of parallelogrammic magnesium oxalate controlled by phosphate species

The shape evolution of magnesium oxalate dihydrate to parallelogrammic micro-particles is closely related to the amount of Na₅P₃O₁₀ participating in the self-assembly of the layer-like parallelogram.

Designed fabrication of anatase mesocrystals constructed from crystallographically oriented nanocrystals for improved photocatalytic activity

In this article, we report a new route to synthesize octahedral anatase mesocrystals (MCs), polycrystals (PCs) and single crystals (SCs) in the TiCl₄–CH₃COOH system just by tuning the reaction time and Ti-source concentration.

Functionalization of carbon nanotubes via Birch reduction chemistry for selective loading of CuO nanosheets

CNTs pass through the inner part of CuO nanosheets, which ensures enhanced conductivity for electron transportation.

Morphology-dependent performance of CuO anodes via facile and controllable synthesis for lithium-ion batteries

Nanostructured CuO anode materials with controllable morphologies have been successfully synthesized via a facile and environmentally friendly approach in the absence of any toxic surfactants or templates. In particular, leaf-like CuO, oatmeal-like CuO, and hollow-spherical CuO were obtained by changing the ligand agents. The structures and electrochemical performance of these as-prepared CuO were fully characterized by various techniques, and the properties were found to be strongly dependent on morphology. As anode materials for lithium-ion batteries, the leaf-like CuO and oatmeal-like CuO electrodes exhibit relatively high reversible capacities, whereas hollow-spherical CuO shows enhanced reversible capacity after initial degradation. Furthermore, an excellent high rate capability was obtained for the leaf-like CuO and hollow-spherical CuO electrodes. These results may provide valuable insights for the development of nanostructured anodes for next-generation high-performance lithium-ion batteries.

Mesocrystals as a class of multifunctional materials

Mesocrystals that consist of crystallographically aligned individual building blocks and controlled level of porosity in between exhibit unique structures and multifunctional behavior.

Flexible CuO nanosheets/reduced-graphene oxide composite paper: binder-free anode for high-performance lithium-ion batteries

Flexible free-standing CuO nanosheets (NSs)/reduced graphene oxide (r-GO) hybrid lamellar paper was fabricated through vacuum filtration and hydrothermal reduction processes. A unique three-dimensional nanoporous network was achieved with CuO NSs homogeneously embedded within the r-GO layers. This hybrid lamellar composite paper was examined as a binder-free anode for lithium ion batteries, and demonstrated excellent cyclic retention with the specific capacity of 736.8 mA h g(-1) after 50 cycles. This is much higher than 219.1 mA h g(-1) of the pristine CuO NSs and 60.2 mA h g(-1) of r-GO film at the same current density of 67 mA g(-1). The high capacitance and excellent cycling performance were generated from the integrated nanoporous structure compose of CuO NSs spaced r-GO layers, which offered an efficient electrically conducting channels, favored electrolyte penetration, and buffered to the volume variations during the lithiation and delithiation process. These outstanding electrochemical capabilities of CuO NSs/r-GO paper holds great promise for flexible binder-free anode for lithium ion batteries.

Synthesis of Li-Mn-O mesocrystals with controlled crystal phases through topotactic transformation of MnCO₃

Mesocrystals of Li-Mn-O compounds, such as LiMn2O4, Li2MnO3, and LiMnO2-Li2MnO3, consisting of oriented nanoscale units were selectively produced under hydrothermal conditions from biomimetically prepared MnCO3 mesocrystals. Topotactic transformation through the intermediate phase of Mn5O8 inheriting a hierarchical structure of the MnCO3 precursor was essential for the formation of the mesocrystal compounds. The crystal phases were successfully controlled by varying the conditions for the hydrothermal reactions. The Li-Mn-O mesocrystals have considerable potential as cathodes of Li-ion batteries.