Cu-O Bond Research Articles

Tecoma stans intermediated green synthesis of copper oxide nanoparticles, its characterization, paracetamol degradation and biological activities

The main objective of the present research work is to green synthesize copper oxide nanoparticles (CuO NPs) and to study its potential against various enmities to safeguard our environment and health. Based on this approach, preparation of CuO NPs was accomplished using four different volumes (10, 25, 40, and 50 mL of leaves extract) of Tecoma stansleaves extract. Moreover, all the synthesized CuO NPs were characterized using XRD, UV–visible, FTIR, and SEM with EDS analysis. From the XRD pattern, the structures of all the synthesized CuO NPs were found to be monoclinic in phase. According to the UV–visible studies, the calculated band gap energy values for all the prepared CuO NPs were higher compared to bulk CuO, which was 1.2 eV. Further, the FTIR results showed the presence of CuO bond and SEM with EDS analysis revealed the surface morphology of CuO NPs andthe presence of elements showing the purity of synthesized CuO NPs, respectively. The optimized condition for the preparation of CuO NPs were 50 mL of leaves extract mixed with 50 mL of double distilled water (CuO4 NPs) showed a spheroidal morphology as evident from the HRTEM images. XPS analysis used to find the oxidation state of detected elements especially for copper and oxygen. The predicted BET and Langmuir surface area of CuO4 NPs were calculated to be 40.305 m2/g and 5074.12 m2/g respectively. Photocatalytic degradation of paracetamol (PCM) using CuO4 NPs was investigated, and the effect of parameters such as pH, initial concentration of PCM solution, and catalyst dosage were studied under UV light irradiation. The highest removal of 95.15 % had been achieved at 120 min under optimized reaction conditions. Additionally, CuO4 NPs also exhibited exemplary antibacterial activity against bacillus subtilis bacteria with a zone of inhibition of 26 mm. Further, in vitro cytotoxic behaviour of CuO4 NPs was estimated using A549 cancer cells by MTT assay. Thus, the green synthesis of CuO NPs using Tecoma stans leaves extract has the capacity to participate in photocatalytic and biological activities.

Synthesis and Characterization of ZnO/Cu<sub>2</sub>O and Co co-doped Ag-ZnO/Cu<sub>2</sub>O Nanoparticles with Possible Photovoltaic Applications

The Photovoltaics phenomenon is one of the major turning points in the battle against the depletion of fossil fuels. Sunlight is the main resource in photovoltaics, but there remains a quest to harvest it efficiently to generate electricity. This study is focused on designing basic, cost-effective prototype solar cells using ZnO/Cu2O nanoparticles (NPs) and Co(cobalt) co-doped Ag-ZnO/Cu2O NPs under normal university laboratory conditions. ITO-coated glass was used as the substrate of the solar cell and a modified low-temperature chemical bath deposition method was used for fabrication. Both ZnO and Cu2O NPs were synthesized by aqueous precipitation methods and the fabrication was performed successfully using ZnO and Cu2O NPs. However, the fabrication with Co co-doped Ag-ZnO and Cu2O NPs requires more research since the Co co-doped Ag-ZnO NPs were synthesized by solvothermal method, and it appeared as a fine powder which was not thick enough to hold onto the Cu2O layer. The UV-spectroscopic analysis confirmed the characteristic band of ZnO NPs at 367.5 nm, Cu2O NPs at 360 nm, and Co co-doped Ag-ZnO NPs at 378 nm. The FTIR spectrum showed sharp peaks at 460 cm-1 and 606 cm-1 for the corresponding Zn-O bond and Cu-O bond, respectively with a broad peak at 1329 cm-1 for Cu2O FTIR, due to the chemisorbed and/or physiosorbed H2O and CO2 molecules on the surface of the nanostructure. The EDX analysis showed the presence of slight carbon impurity in ZnO NPs which resulted in a deviated XRD pattern while Cu2O NPs showed the characteristic XRD pattern. The solar cell illuminated under three different lux conditions, had the characteristic J-V plot when measured through Gamry Potentiostat.

Unraveling the influence of oxygen vacancy with and without replacement on Cu<i>2</i>O: A DFT Study

This study delves into the structural and electronic effects of oxygen vacancies in Cu2O using density functional theory (DFT) enhanced with Hubbard U corrections (DFT+U). A 3x2x1 supercell of Cu2O was employed. The study meticulously investigates the removal of 1, 2, and 3 oxygen atoms, analyzing the ensuing changes in both structural stability and electronic properties, with particular emphasis on the band gap.The structural analysis revealed that oxygen vacancy formation induces significant modifications in Cu-O and Cu-Cu bond lengths, with elongations observed around the vacancy sites in which the Cu-Cu bond length decreased to 2.4035 Å, compared to 3.0066 Å in the pristine structure. The structural distortion followed the Jahn-Teller effect, leading to the formation of isolated units and transformation in bond angles. The introduction of oxygen vacancies without replacement (WOR) caused significant distortions in the Cu2O lattice, which were more pronounced with increasing vacancy concentration. The Cu-O bond length increased from 1.8492 Å in the pristine structure to 1.9840 Å in the single vacancy configuration. However, in the oxygen vacancies with replacement (WR) the Cu-Cu bond length increased slightly to 3.0218 Å, with the Cu-O bond length expanding to 1.8505 Å. The band structure analysis indicated a decrease in the band gap with increasing vacancy concentration. The pristine Cu2O exhibited a band gap of 1.67 eV as calculated, which was increased to 1.97 eV with a single vacancy and 1.16 eV with two vacancies, reflecting the significant impact of oxygen vacancies on the material’s optoelectronic properties. The findings underscore the critical role of oxygen vacancies in modulating the structural and electronic properties of Cu2O, providing insights that are pivotal for optimizing its performance in applications like photocatalysis and solar cells.

Structural, Morphological, Optical and Vibrational Properties of a Novel Coral-Like Fibrous CuO Nanostructure Synthesized via Dropwise Precipitation for UV-light Induced Photocatalytic Wastewater Remediation on Aqueous R6G Dye

CuO is a well-known monoclinic structure with unique properties that is extensively investigated for sensor, energy storage, and optoelectronic applications. In this work, the CuO nanostructure was synthesized through facile precipitation by mixing the aqueous copper (II) sulfate pentahydrate with sodium hydroxide. The as-synthesized CuO was characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy. A homogeneous growth of a narrow, fine coral-like fibrous morphology was observed on CuO under SEM imaging. The FTIR spectra reveal the existence of some dominant sharp bands in the lower wavenumber region that represent the Cu-O bonds. The high solubility of CuO in water confirms the formation of particles with nanoscale dimensions. CuO exhibits a strong optical absorption peak at 510 nm, and the band gap determined by Tauc's relation is 2.11 eV. CuO is capable of inducing photocatalytic degradation on R6G dye solutions under low-intensity UVC irradiation, which can serve as a future photocatalyst for wastewater treatment.

Adjusting the Covalency of Metal-Oxygen Bonds in CuBi2O4 by Zn Cation Doping to Achieve Highly Efficient Photocathodes.

Zn doped CuBi2O4 photocathodes are prepared by using a low-cost solution-based spray pyrolysis method. The doping of Zn in CuBi2O4 promotes the separation and migration of carriers and effectively increases the carrier density. Compared with CuBi2O4 alone, the photoelectrochemical activity of the Zn doped CuBi2O4 photoelectrode is improved with the photocurrent density of -0.56 mA/cm2 at 0.4 V vs. RHE. This improvement is due to the lower electronegativity of Zn, which leads to the covalent increase of Cu-O and Bi-O bonds in CuBi2O4, which limits the recombination of photogenerated electrons and holes and improves charge separation and transport. This study presents an innovative approach to enhance the charge separation efficiencies of photocathodes by implementing element doping strategies, which may contribute to further research on photocatalytic water splitting.

A novel green nanocomposite for EOR: Experimental Investigation of IFT Reduction, wettability Shift, and nanofluid stability

A stable nanofluid (NF) is crucial for success of nano-enhanced oil recovery (nEOR) processes. However, this represents a significant challenge as nanoparticles (NPs) tend to agglomerate under high salinity and NP concentration adversely affecting the oil recovery. New nanomaterials including functionalized nanoparticles also known as nanocomposites (NC) can help to overcome these issues. In this paper, first, we reported synthesis, characterization, and performance evaluation of a novel hydrophobic CuO-SiO2-Montmorillonite-K+-Thiazine NC for the first time. The NC was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-Ray Diffraction (XRD), Thermogravimetry Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR). SEM analysis showed that the NC is composed of uniformly distributed NPs. EDAX results confirmed presence of Cu, SiO2, O2, and Cl in the NC. XRD analysis indicated that SiO2 is the dominant phase in the crystal lattice and responsible for adsorption capacity of the NC. TGA analysis showed that the NC will be thermally stable in typical reservoir temperatures (∼80°C). FTIR results confirmed presence of Si-O, Cu-O, Si-O-Si, Al-O-Si, Al-OH, and OH bonds in the NC. In the second phase of this research work, the novel NC was used to investigate recovery of a Kazakhstani paraffinic heavy crude oil from Berea sandstone with focus on IFT reduction, oil recovery, wettability alteration, and stability analysis of the NFs. NFs were prepared with NC concentrations of 250, 500, and 1,000 ppm using moderate salinity (MS), low salinity (LS), and distilled water (DW). The results showed that the optimal NF (250 ppm LS) exhibited a high zeta potential value (−65.5 mV) indicating a high stability which is superior to all of the previously reported NCs. This high stability is attributed to use of thaizine as a source of natural surfactant. The optimum NF also altered the wettability of the sandstone by 77.6% and the contact angle (CA) was reduced from 117.9° to 26.4° making the system strongly water wet. The nanoclay has significantly facilitated the wettability alteration. The optimum NF also reduced the IFT by 92.3% from 27.42 mN/m to 2.11 mN/m. An incremental oil recovery of 20% was also achieved in the tertiary or EOR stage of oil. A comparison with the NCs reported in the literature confirmed the excellent performance of this novel NC in terms of NF stability, IFT reduction, and wettability alteration. The novel NC has a great potential for nEOR and other oilfield and environmental applications.

Copper-induced lattice distortion in Na4Fe3(PO4)2(P2O7) cathode enabling high power density Na-ion batteries with good cycling stability

Na4Fe3(PO4)2P2O7 (NFPP) has attracted attention due to its high theoretical capacity, low cost, and good structure stability for Na-ion batteries. However, its practical application is limited by the low intrinsic electronic conductivity and sluggish ion diffusion kinetics. To tackle those problems, lattice strain engineering by heteroatom doping is applied to tune the local molecular structure and optimize the electrochemical properties of electrode materials. Copper cation (+2) with a smaller ionic radius was chosen to dope at Fe-site in NFPP, and the doping amount was also optimized, illustrating the optimized sample of Na4Fe2.7Cu0.3(PO4)2P2O7 (NFPP-0.3Cu) delivered a high capacity of 119.01 mAh g-1 at 1C (1 C = 129 mA g-1) and a high capacity retention of 82.76% after 3000 cycles at 20 C. Notably, full cells with NFPP-0.3Cu as cathode and hard carbon as anode delivered a high energy density of 230 Wh kg-1 and a power density of 2280 W kg-1. The exceptional electrochemical performances are attributed to the modulated electronic structure and abundant lattice defects by Cu-doping. Furthermore, in-situ X-ray diffraction technique and theoretical calculation have jointly proved that the lattice distortions originated from Cu-doping have reduced the band gap of the NFPP-0.3Cu and altered the coordination environment of Fe, shortening the Fe-O and Cu-O bond lengths, significantly enhancing the intrinsic ionic conductivity and the diffusion kinetics of Na+. This work provides new point of views on lattice strain engineering and reaction kinetics of cathode materials in promoting high energy and power density sodium-ion batteries.

8-Hy-droxy-quinolinium tri-chlorido-(pyridine-2,6-di-carb-oxy-lic acid-κ3 O,N,O')copper(II) dihydrate.

The title compound, (C9H8NO)[CuCl3(C7H5NO4)]·2H2O, was prepared by reacting CuII acetate dihydrate, solid 8-hy-droxy-quinoline (8-HQ), and solid pyridine-2,6-di-carb-oxy-lic acid (H2pydc), in a 1:1:1 molar ratio, in an aqueous solution of dilute hydro-chloric acid. The CuII atom exhibits a distorted CuO2NCl3 octa-hedral geometry, coordinating two oxygen atoms and one nitro-gen atom from the tridentate H2pydc ligand and three chloride atoms; the nitro-gen atom and one chloride atom occupy the axial positions with Cu-N and Cu-Cl bond lengths of 2.011 (2) Å and 2.2067 (9) Å, respectively. In the equatorial plane, the oxygen and chloride atoms are arranged in a cis configuration, with Cu-O bond lengths of 2.366 (2) and 2.424 (2) Å, and Cu-Cl bond lengths of 2.4190 (10) and 2.3688 (11) Å. The asymmetric unit contains 8-HQ+ as a counter-ion and two uncoordinated water mol-ecules. The crystal structure features strong O-H⋯O and O-H⋯Cl hydrogen bonds as well as weak inter-actions including C-H⋯O, C-H⋯Cl, Cu-Cl⋯π, and π-π, which result in a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing involving the main residues are from H⋯Cl/Cl⋯H inter-actions, contributing 40.3% for the anion. Weak H⋯H contacts contribute 13.2% for the cation and 28.6% for the anion.

Three novel dithiocarbamate surfactants: Synthesis, DFT calculation and flotation mechanism to chalcopyrite

Three novel dithiocarbamate surfactants including 2-hydroxypropyl diethyldithiocarbamate (HPD-2), 3-hydroxypropyl diethyldithiocarbamate (HPD-3), and 2-(2-hydroxyethoxy)ethyl diethyldithiocarbamate (HED-2) were prepared and characterized by FTIR, 1H/13C NMR and HRMS. They were first employed as collectors to float chalcopyrite. DFT calculations were performed to anticipate the structure–reactivity of the novel dithiocarbamates, revealing that the reaction sites were primarily distributed in CS and OH groups. Compared with HPD-2 and HPD-3, HED-2 possessed a higher chemical reactivity owing to the C-O-C group. Microflotation results indicated that the collecting ability of the three dithiocarbamate collectors towards chalcopyrite followed as HPD-3 > HED-2 > HPD-2. FTIR and XPS demonstrated that HED-2 chemisorbed onto the surface of chalcopyrite through newly generated CuS and CuO bonds.

Topography control and component design strategies to enhance electrochemical performance of O3-Type cathode materials for Sodium-ion batteries

Layered transition metal oxides (NaxTMO2, 0 < x ≤ 1) are considered one of the most promising cathodes for Sodium-ion batteries (SIBs) due to their high theoretical capacity and operability. However, NaxTMO2 still faces significant challenges, including poor kinetic performance and low energy efficiency. Herein, in order to enhance the kinetics of NaNi1/3Fe1/3Mn1/3O2 (NaNFMO), topography control and component design were proposed: First, Cu doping (Cu-NaNFMO) was used to expand lattice channels and improve “flat sheet” of layered oxide, which synergistically enhanced transport kinetics of Na+. Second, Co coating (NaNFMO@Co) reacted with surface residue to form a fast-ionic conductor NaxCoO2 (0 < x ≤ 1), which inhibited interfacial side reactions and enhanced transport kinetics of Na+. Furthermore, the presence of strong Cu-O bonds in Cu-NaNFMO and fast-ionic conductor NaxCoO2 in NaNFMO@Co led to better electrochemical redox performance, the initial charge specific capacity of NaNFMO was increased from 141.5 mAh g⁻1 to 145.8 mAh g⁻1 and 144 mAh g⁻1, with capacity retention improving by nearly 10 % after 100 cycles. Furthermore, NaNFMO@Co improves ICE from 90.56 % to 93.57 %. With the improved kinetics, the DCR of pouch cells decreased, and the energy efficiency increased from 93.3 % to 94 % and 95.7 %.

Micelle-modulated ribonuclease-like activities of oxo-bridged binuclear copper(ii) complexes with novel imidazole derivatives

Three bis-tridentate imidazole derivatives as ligands and their alkoxo-bridged binuclear copper(II) complexes (1, 2 and 3) were synthesized and characterized. Single crystals show that furan or thiophene moiety of 2 or 3 is free without a coordination with the central copper. Five-coordinated structure of 1 is constructed via two Cu-N and three Cu-O coordination bonds involving the participation of phenolic oxygen, alkoxo-bridged oxygen and the one carboxylate oxygen. Furthermore, catalytic reactivity of the as-synthesized binuclear complexes was evaluated for the transesterification of classic RNA model HPNP (2-hydroxypropyl-4-nitrophenyl phosphate). Overall, three complexes displayed the almost similar activity in both non-micellar and micellar solutions. HPNP transesterification achieved more obvious acceleration in micellar solutions of three kinds of cationic surfactants. All of three complexes obtained relatively good reactivity in CTAB micellar solution, respectively achieving approximately 804-fold (for 1), 762-fold (for 2) and 785-fold (for 3) rate enhancement compared to background rate of HPNP spontaneous cleavage. The as-synthesized binuclear complexes displayed approximately two times dominative activity in CTAB micellar solution over that in the non-micellar system. However, to some extent the introduction of amphoteric n-lauroylsarcosine sodium (LSS) and non-ionic polyoxyethylene lauryl ether (Brij35) inhibited the catalytic transesterification of HPNP. This study is beneficial to the design and application of novel mimic esterolases.

Cu Regulating the Bifunctional Activity of Co-O Sites for the High-Performance Rechargeable Zinc-Air Battery.

The rational design of cost-effective and highly active electrocatalysts becomes the crucial energy storage technology to boost the kinetics of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), which hinders the large-scale application of metal-air batteries under the situation of increasingly pressing energy anxiety. Herein, the Co-based ZIF introduced the moderate amount of Cu2+-derived Cu/Co metal nanoparticles (NPs) embedded in carbon frameworks after high-temperature calcination. The Co-O bond on the surface of Co nanoparticles is modulated by adjacent Cu nanoparticles with the surface Cu-O bonds. The resulted increase of the Co2+/Co3+ ratio in 0.1CuCo-NC enhances the ORR/OER bifunctional catalytic kinetics along with the ΔE of 0.639 V. In situ Raman spectra of the catalyst on the three-electrode system as well as in the driven zinc-air battery (ZAB) show that the Co-O active sites regulated by Cu nanoparticles with Cu-O bonds maintain a periodic lattice expansion and compression during discharging and charging. The zinc-air battery based on 0.1CuCo-NC has a peak power density of up to 198.3 mW cm-2, a mass-specific capacity of 798.2 mAh g-1, and a cycling stability of 923 h at room temperature. This work makes up the research gap of a Co-based metal-organic framework (MOF)-derived catalyst regulated by a transition metal.

Study of Microstructure, Morphology and Functional Groups of Titanium Dioxide (Tio2) Impregnated With Copper (Cu)

This research aims to determine the differences in the microstructure, morphology, and functional groups of TiO2 (P-25) after being impregnated with Cu. Cu-impregnated TiO2 samples are synthesized using the impregnation method with TiO2 (P-25) and copper sulfate as precursors. The microstructure and functional groups of TiO2 (P-25) and Cu-TiO2 were investigated using X-ray diffraction (XRD), scanning electron microscope-energy dispersive x-ray (SEM-EDX), and Fourier transform infrared (FTIR) analysis. The lattice parameters (a, b, and c) of the TiO2 sample were found to be a = b = 0.3778 nm, c = 0.9494 nm, and these values increased to a = b = 0.3779 nm, c = 0.9496 nm after the addition of Cu. The distance between the lattices of the TiO2 sample was measured at 0.3505 nm and increased to 0.3509 nm after Cu addition. The average crystallite size of the TiO2 sample was 33 nm, which increased to 43 nm after Cu impregnation. The strain value decreased from 2.76×10^(-3) to 1.82×10^(-3) after Cu addition. SEM results revealed that the morphology of the particles from the Cu-doped synthesis showed agglomeration. The success of Cu doping was confirmed by EDX mapping, which showed the presence of Ti, O, and Cu evenly distributed on the TiO2 surface. The FTIR spectrum indicated that TiO2 (P-25) and Cu-TiO2 particles had absorption peaks at similar wave numbers. However, in the absorption area of 1000 cm^-1 to 1250 cm^-1, new absorption bands affiliated with Cu-O bonds appeared in the Cu-TiO2 sample, resulting from TiO2 vibrations after Cu addition.

Catalytic Water Electrolysis by Co-Cu-W Mixed Metal Oxides: Insights from X-ray Absorption Spectroelectrochemistry.

Mixed metal oxides (MMOs) are a promising class of electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Despite their importance for sustainable energy schemes, our understanding of relevant reaction pathways, catalytically active sites, and synergistic effects is rather limited. Here, we applied synchrotron-based X-ray absorption spectroscopy (XAS) to explore the evolution of the amorphous Co-Cu-W MMO electrocatalyst, shown previously to be an efficient bifunctional OER and HER catalyst for water splitting. Ex situ XAS measurements provided structural environments and the oxidation state of the metals involved, revealing Co2+ (octahedral), Cu+/2+ (tetrahedral/square-planar), and W6+ (octahedral) centers. Operando XAS investigations, including X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), elucidated the dynamic structural transformations of Co, Cu, and W metal centers during the OER and HER. The experimental results indicate that Co3+ and Cu0 are the active catalytic sites involved in the OER and HER, respectively, while Cu2+ and W6+ play crucial roles as structure stabilizers, suggesting strong synergistic interactions within the Co-Cu-W MMO system. These results, combined with the Tafel slope analysis, revealed that the bottleneck intermediate during the OER is Co3+ hydroperoxide, whose formation is accompanied by changes in the Cu-O bond lengths, pointing to a possible synergistic effect between Co and Cu ions. Our study reveals important structural effects taking place during MMO-driven OER/HER electrocatalysis and provides essential experimental insights into the complex catalytic mechanism of emerging noble-metal-free MMO electrocatalysts for full water splitting.

Altering the CO2 Electroreduction Pathways Towards C1 or C2+ Products via Engineering the Strength of Interfacial Cu-O Bond.

Copper (Cu)-based catalysts have established their unique capability for yielding wide value-added products from CO2. Herein, we demonstrate that the pathways of the electrocatalytic CO2 reduction reaction (CO2RR) can be rationally altered toward C1 or C2+ products by simply optimizing the coordination of Cu with O-containing organic species (squaric acid (H2C4O4) and cyclohexanehexaone (C6O6)). It is revealed that the strength of Cu-O bonds can significantly affect the morphologies and electronic structures of derived Cu catalysts, resulting in the distinct behaviors during CO2RR. Specifically, the C6O6-Cu catalysts made up from organized nanodomains shows a dominant C1 pathway with a total Faradaic efficiency (FE) of 63.7 % at -0.6 V (versus reversible hydrogen electrode, RHE). In comparison, the C4O4-Cu with an about perfect crystalline structure results in uniformly dispersed Cu-atoms, showing a notable FE of 65.8 % for C2+ products with enhanced capability of C-C coupling. The latter system also shows stable operation over at least 10 h with a high current density of 205.1 mA cm-2 at -1.0 VRHE, i.e., is already at the boarder of practical relevance. This study sheds light on the rational design of Cu-based catalysts for directing the CO2RR reaction pathway.

Unlocking the potential of multicomponent mesoporous bioactive glass nanoparticles: An approach to enhanced ion therapy

This work presents the synthesis and characterization of a multicomponent mesoporous bioactive glass (MMBG) derived from the composition of 58S glass modified with copper, zinc, and boron. Morphological data revealed the presence of spherical particles with an average size of 616 nm and a specific surface area of 295 m2·g−1. X-ray diffractogram analysis confirmed the lack of long-range order in the MMBG, indicating the presence of a disordered vitreous structure characteristic of glass. The structural scenario of the bioactive glass MMBG reveals a characteristic configuration of borosilicate glasses, where the [BO4] polyhedra, along with SiO4 tetrahedra, constitute the backbone of the glassy matrix. Concerning zinc and copper ions, they function similarly to calcium in compensating for the remaining negative charges within the borosilicate network, behaving as typical network-modifying ions. The presence of these heavy ions, coupled with the formation of the borosilicate network in MMBG, led to a 20 % increase in density compared to 58S glass. Additionally, alterations in the chemical composition and structure of MMBG resulted in a reduction in molar volume compared to 58S, indicating a decrease in the volume occupied by one mole of oxygen in the glass matrix, thereby increasing the oxygen packing density. The pH studies reveal that changes in the chemical composition of MMBG did not compromise its chemical reactivity in aqueous environments. The capability of MMBG glass to act as a bioactive agent for ion therapy is evidenced by its ability to deliver Zn and Cu ions, as substantiated by the gradual disappearance of absorption in wavenumber range of 690–470 cm−1, attributed to the vibration of Zn-O and Cu-O bonds. Preliminary in vitro assay for bioactivity in SBF revealed that the formation of apatite layer on the surface of MMBG glass was notably thicker and denser compared to 58S glass. This result highlights the superior bioactive response of the MMBG bioactive glass, indicating its potential as an exceptionally favorable material for various biomedical applications.

Assessment of superconducting and structural stability of advanced Y-123 and Y-358 ceramics with Tb/Y substitution in main matrices

In this study, the performances of Y1-x(Tb)xBa2Cu3O7-δ (Y-123) and Y3-x(Tb)xBa5Cu8O18-δ (Y-358) advanced ceramics prepared by sol-gel preparation route are investigated by the advanced characterization methods including X-ray diffraction (XRD), temperature dependent resistivity (ρ-T), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and energy distribution spectroscopy (EDS) measurements and theoretical approaches. The EDS results illustrated that the Tb impurities were replaced successfully by the yttrium sites in the YBa2Cu3O7-y main matrix. Similarly, it was noted that the presence of excess impurities in the crystal structure led to the oxygenation problems. Electrical properties were determined by temperature dependent resistivity (ρ-T) measurements. ρ-T results indicated that Tb doping reduced the critical transition temperature (Tc) values for the transition to superconductivity for all samples in two YBCO phases. Although it appears to have negative effects of Tb ions on the number of mobile charge carrier concentrations in the σ antibonding in-plane Cu-O bonds, bipolaron formations in the polarizable lattices, oxidation states, and amplitude of the pair wave function of both phases, the other valuable properties (morphology, crystallinity quality, interaction between adjacent layers, critical current density, and flux pinning ability) were noted to improve remarkably in the case of the optimum amount in the Y-123 superconducting phase. In this context, the Y-358 superconducting phase was harshly affected by the substitution due to the change of the ortorombicity, localization problem, impurity phases, structure stabilization, crystal structure quality, crystallization system, homogeneities of oxidation states, oxygen ordering degree, and impurity scatterings. Besides, the analysis of the fluctuation induced conductivity indicated that the Y-123 ceramics with longer c-axis coherence length and less anisotropic nature exhibited well superconducting properties. Additionally, the doping ratio of x=0.01 led to the formation and distribution of more nucleation centers for the thermal fluxon motions of 2D pancake vortices. Similarly, the optimum Tb doped Y-123 system exhibited much durable to applied field strengths due to the best interaction quality between grains. Accordingly, this study recommended that the Y1-x(Tb)xBa2Cu3O7-δ advanced ceramic structure with new functionalities can find much more application areas in innovative, heavy-industrial technologies, and advanced engineering-related sectors.

Simultaneous Cu(II)-EDTA decomplexation and Cu(II) recovery using integrated contact-electro-catalysis and capacitive deionization from electroplating wastewater

The complex of heavy metals and organic acids leads to high difficulty in heavy metals separation by traditional technologies. Meanwhile, alkaline precipitation commonly used in industry causes the great consumption of resources and extra pollution. Herein, the effective decomplexation of Cu(Ⅱ)-EDTA and synchronous recycling of Cu2+ were realized by contact-electro-catalysis (CEC) coupled with capacitive deionization (CDI) innovatively. In particular, fluorinated ethylene propylene (FEP) as dielectric powders could generate reactive oxygen species under ultrasonic stimulation, realizing continuous deaminization and decarboxylation of Cu(Ⅱ)-EDTA and accelerating the totally breakage of Cu-O and Cu-N bonds. Additionally, the degradation pathway and intermediates evolution of Cu(Ⅱ)-EDTA were investigated using various characterization methods. It was confirmed that decarboxylation predominantly governed the degradation process of Cu(Ⅱ)-EDTA in CEC. During the course of treatment, the degradation ratio of Cu(Ⅱ)-EDTA reached 86.4 % within 150 min. Impressively, this strategy had satisfactory applicability to other metal combinations and excellent cycle stability. Subsequently, the released Cu ions were captured by CuSe cathode electrode through CDI. This research elucidated the degradation mechanism of persistent organic pollutant during CEC, and provided a novel approach for efficiently treating industrial wastewater containing metal complexes and advancing the exploitation and utilization of new technologies for metal recovery.

Switching CO2 Electroreduction toward Ethanol by Delocalization State-Tuned Bond Cleavage.

The electrochemical CO2 reduction reaction by copper-based catalysts features a promising approach to generate value-added multicarbon (C2+) products. However, due to the unfavored formation of oxygenate intermediates on the catalyst surface, the selectivity of C2+ alcohols like ethanol remains unsatisfactory compared to that of ethylene. The bifurcation point (i.e., the CH2═CHO* intermediate adsorbed on Cu via a Cu-O-C linkage) is critical to the C2+ product selectivity, whereas the subsequent cleavage of the Cu-O or the O-C bond determines the ethanol or ethylene pathway. Inspired by the hard-soft acid-base theory, in this work, we demonstrate an electron delocalization tuning strategy of the Cu catalyst by a nitrene surface functionalization approach, which allows weakening and cleaving of the Cu-O bond of the adsorbed CH2═CHO*, as well as accelerating hydrogenation of the C═C bond along the ethanol pathway. As a result, the nitrene-functionalized Cu catalyst exhibited a much-enhanced ethanol Faradaic efficiency of 45% with a peak partial current density of 406 mA·cm-2, substantially exceeding that of unmodified Cu or amide-functionalized Cu. When assembled in a membrane electrode assembly electrolyzer, the catalyst presented a stable CO2-to-ethanol conversion for >300 h at an industrial current density of 400 mA·cm-2.

Cu-O-Si-C interface-induced high-adhesion and anticorrosion of the DLC coatings on inner wall of copper tube prepared by PECVD

Deposition of well-adherent diamond-like‑carbon (DLC) films on copper is relatively difficult due to weak bonds between copper and carbon. The Cu-O-Si-C nanostructure was proposed to improve the adhesion and the corrosion-resistance of multilayer Si-DLC/DLC film on an inner surface of copper tube prepared by PECVD. First, the copper alloy was pretreated by oxygen. Then mixture gas of tetramethylhexylsilane (TMS) and oxygen was used to deposit interlayer, and finally multilayer Si-DLC/DLC film was deposited using the gas C2H2 and argon. Transmission Electron Microscope (TEM) demonstrated that there existed CuSiO3, CuO, SiC, SiO2 nanostructures in the interlayer. And X-ray Photoelectron Spectroscopy (XPS) proved that there were actually CuO, SiC and SiO bonds at the interface. These bonds and compounds enhanced the adhesion between multilayer Si-DLC/DLC film and copper substrate. The polarization potential was significantly improved to −0.07 V, achieved through the process of oxygen pre-implantation and the combined deposition of oxygen and TMS. Furthermore, the adhesion of the film was estimated by the Rockwell test and reached HF1-HF2. The Cu-O-Si-C microstructure plays a crucial role in enhancing the adhesion and corrosion resistance of multilayer Si-DLC/DLC film.