Good Crystallinity Research Articles

Enhanced Photocatalytic Degradation of Selected Contaminant Dyes from Textile Sewage Discharge and Electrochemical Efficiency using Citrus limetta Mediated ZnO Nanopellets

T his study focuses on the phyto mediated synthesis of zinc oxide nanoparticles (ZnO-NPs) using Citrus limetta extract and evaluates their antimicrobial, photocatalytic, and electrochemical properties. Structural analysis by XRD confirmed good nano crystallinity with an average crystallite size of 16.29 nm and the band gap of 3.2–3.33 eV indicated semiconductor behavior. FTIR analysis revealed Zn-O bonds and functional groups. TEM showed a particle size distribution of 20-50 nm. ZnO-NPs demonstrated significant antibacterial activity against Vibrio cholerae, suggesting potential for cholera resistance. They also exhibited excellent performance as electrode materials with a specific capacitance of 200.16 F/g and effective photocatalytic degradation of methylene blue and Congo red dyes.

Carboxymethyl cellulose assisted hydrothermal synthesis of litchi-like zinc ferrite nanoparticles for water remediation through visible photo-Fenton-like catalysis

The conventional methods for the synthesis of zinc ferrite (ZnFe2O4) basically require high temperature calcination oxidation step, which produces environmentally unfriendly high energy consumption and may produce harmful gases that pollute the atmosphere, as well as the calcination synthesis limits the application of ZnFe2O4 such as preparation of organic composite materials. To end this, by adding carboxymethyl cellulose (CMC) to the reaction system, homogeneous litchi-like ZnFe2O4/CMC nanoparticles were successfully synthesized without alkali and calcination in this paper. The rich carboxyl group of CMC is conducive to the chelation and fixation of metal ions in the reaction precursor, which greatly promotes the synthesis of ZnFe2O4. The synthesized particle size is ~100 nm, with obvious ZnFe2O4 diffraction peaks and good crystallinity. The photocatalytic performance of the synthesized photocatalyst was evaluated by visible light-Fenton-like method. With the activation of peroxymonosulfate (PMS), 80.27 % of tetracycline hydrochloride (TC) was degraded in just 18 min, suggesting that the synthesized catalyst had an excellent photocatalytic performance. After four cycles, the catalyst still could degrade 64.52 % TC. And the same behavior in XRD and FTIR spectra confirms the stability of the photocatalyst. In addition, it was determined that singlet oxygen (1O2) dominated the visible light catalytic degradation.

Sustainable visible light-driven catalysis using Ca-doped ZnO nanoparticles via sol-gel methodology

In current research, we investigated the optical parameters of ZnO based nanomaterials (pure and Ca-doped ZnO nanostructures). X-ray diffraction study examined that nanostructures had good crystallinity and phase purity. Furthermore, energy-dispersive Xray spectroscopy reported the composition of nanomaterials and scanning electron microscopy (SEM) also illustrated the surface morphology of nanomaterials. Photoluminescence and UV-visible spectroscopy were employed to explore the optical features. It was observed from results that 3% calcium-doped zinc oxide exhibited highest efficiency in the degradation of both MB and MO dyes. Notably, the highest degradation efficiency achieved for MB and MO was 84% and 89%, respectively.

Enhanced Charge Transfer in Poly(Heptazine Imide) Synergistically Induced by Donor-Acceptor Motifs and Ohmic Junctions for Efficient Photocatalytic CO2 Reduction.

Poly(heptazine imide) (PHI) has received widely interest in the photocatalytic CO2 reduction due to its good crystallinity and complete in-plane structure. However, its poor photo-induced carrier separation and migration efficiency and insufficient active sites results in undesirable photocatalytic CO2 reduction performance. Herein, we designed and constructed a novel ohmic junction photocatalyst by integrating melamine edge-modified PHI (mel-PHI) with extended π-conjugated system with TiN (TiN/mel-PHI) for enhancing the photocatalytic CO2 reduction activity. Strikingly, the photocayalytic CO2 reduction yield of the optimal TiN/mel-PHI is 62.64 µmol·g-1·h-1, which is 5.6 and 2.8 times higher than PHI (11.26 µmol·g-1·h-1) and mel-PHI (22.32 µmol·g-1·h-1), respectively. The superior photocatalytic CO2 reduction activity is attributed not only to the formation of D-A structure by the introduction of melamine, which extends the π-conjugation system, alters the electronic structure of PHI, and accelerates the charge separation and migration, but also to the induced internal electric field by ohmic junction further enhances the charge separation and migration efficiency. Meanwhile, the synergistic effect of mel-PHI and TiN enriched the electron number of TiN, reducing the CO2 reduction potential. This work highlights the synergistic enhancement of charge transfer between D-A motifs and ohmic junctions, confirming their potential in optimizing photocatalysts.

Novel Syntheses of Wide-Band Gap Semiconducting CdxZnx−1Co2O4 of Spinel Nanostructure: Characterization and Optical Properties

AbstractCadmium doped zinc cobaltite spinel structure in the form of CdxZnx-1Co2O4 (0 ≤ x ≤ 1) are synthesized by sol-gel method. The energy dispersive X-ray spectra confirm the synthesis of pure ZnCo2O4 and Cd doped samples nanoparticles. Scanning and transmission electron microscopes images of Cd ZnCo2O4 samples show the cubic crystal structure of the nanoparticles. A good crystallinity of the ZnCo2O4 and its dopants samples are indicated by the sharpness and strong peaks of X-ray diffraction patterns. The particle size is independent of the ratio of incorporated Cd into the ZnCo2O4 matrix. The FT-IR transmission spectrum of each Cdx Zn1-xCo2O4 complex shows two strong vibration peaks that are ascribed to the spinel structure’s octahedral and tetrahedral. The absorption spectra reveal three distinct absorption characteristics for Cdx Znx-1Co2O4 peaking at 268, 532 and 778 nm due to the photoexcitation of electrons from O 2p to Co 3d transitions and d-d transition of Co 3d. N2 adsorption–desorption isotherms for Cdx Znx-1Co2O4 indicate are carried out.

Facile synthesis of polyhedral oligomeric silsesquioxanes with excellent thermosetting, fibrous and crystalline properties

The development of multifunctional polyhedral oligomeric silsesquioxanes (POSS) that are more serialized than traditional POSS is essential to reduce the economic investment and expand the category of high-performance POSS. This work employed a simple one-step method to synthesize a series of different physical states of methacryloxypropyl-phenyl POSS (AcPhPOSS). The FTIR, NMR and MS results showed that the products were mainly composed of regular T8, T10 and T12 cage-like structures, and the outer periphery of the AcPhPOSS cage carried different proportions of flexible methacryloxypropyl (R1) and rigid phenyl (R2) groups. In addition, the curable, fibrous, and crystalline properties of liquid, semi-solid, and powder AcPhPOSS were studied through thermal curing, electrospinning, and crystallization methods, respectively. The results showed that AcPhPOSS in three different states, especially AcPhPOSS@1:0 (liquid), AcPhPOSS@1:3 (semi-solid) and AcPhPOSS@0:1 (powder), exhibited good thermal curing properties, fiber and crystallization, respectively. Hence, this work proposes a facile strategy for producing multifunctional materials with good curing properties, fiber-forming properties, and crystallinity, which have broad application potential in thermosetting resins, fiber materials, and single crystal materials.

Synthesis, Chiroptical Properties, and Absolute Configuration Determination of Phenyl‐4‐pyridyl‐2,5‐dipyrimidinylmethane

Phenyl‐4‐pyridyl‐2,5‐dipyrimidinylmethane (1) has been synthesized in five steps from 5‐methylpyrimidine. The structural feature of 1 is the symmetry elements with respect to the 180º rotation of the aryl group along the central C‐C bonds. Due to this structural feature, the compound 1 is expected the good crystallinity despite of the asymmetric molecular structure. The optical resolution of 1 was achieved by high performance liquid chromatography using chiral stationary phase (chiral HPLC). The circular dichroism (CD) spectra of the two fractions showed opposite signs. As expected, the X‐ray crystallographic analysis was successfully performed for both the racemic and enantiomerically pure crystals of compound 1, with the nitrogen atoms being unambiguously assigned in both cases. It was concluded the first‐eluted fraction in chiral HPLC was determined to be S configuration both by the CD calculation for reproducing the experimental CD spectrum and by the anomalous diffraction of X‐ray crystallographic analysis of enantiomerically pure 1.

Biphasic interface templated synthesis of wrinkled MOFs for the construction of cascade sensing platform based on the encapsulated gold nanoclusters and enzymes

The design and construction of MOFs with flower-like structure could afford sufficient space for the immobilization of guests with large size and interconnected transport channels for their mass diffusion although it remains a challenge. Herein, wrinkled Ce-based hierarchically porous UiO-66 (Ce-WUiO-66) with good crystallinity was successfully synthesized for the first time using bicontinuous emulsion composed of 1-heptanol, water and F127 (PEO106PPO70PEO106) surfactant as a template. F127 played a key role in the formation of emulsions as a stabilizer, and meanwhile its PEO segments interacted with MOF precursors to guide the evolvement of crystallized pore walls. Through controlling the ratios of heptanol to water and the salinity, the distances of the pleat openings and the morphology of the resultant Ce-WUiO-66 were facilely regulated. In virtue of its highly open radial structure, Ce-WUiO-66 could serve as an ideal platform for loading multiple substances to build a cascade sensing system. As a proof of concept, we designed an amino acid (AA) cascade probe by co-immobilizing gold nanoclusters (AuNCs) and LAA oxidase into Ce-WUiO-66. The aggregation-induced-emission enhancement resulted from the encapsulation of AuNCs into Ce-WUiO-66 significantly improved the detection sensitivity and the detection limit of corresponding substrates reached as low as 10-8 M. The proposed biphasic interface assembly strategy is hopefully to provide a new route for the rational design of MOFs with various open pore structure and broaden their potential applications with multiple large-size substances involved besides the currently exemplified cascade sensing platform.

Core‐shell Structured Nano CuO@CER Composites for the Photoelectrocatalytic Degradation of Methylene Blue

AbstractThe composite material of nano CuO loaded on ion exchange resin (CuO@CER) as the carrier was prepared successfully by constant temperature oscillation and hydrothermal synthesis methods. It was applied to the photoelectrocatalytic degradation of methylene blue (MB) as an organic pollutant, and further to explore the optimal conditions for CuO@CER photoelectrocatalytic degradation of MB. The results showed that the composite material had a typical core‐shell structure, and the nano CuO loaded on the ion exchange resin had good crystallinity and high purity. CuO@CER exhibited excellent photocatalytic and photoelectrocatalytic performance towards MB, with degradation rates of 92.02% and 95.20% in 70 min under their respective optimal reaction conditions. Furthermore, the photoelectrocatalytic stability of CuO@CER was good relatively, and the degradation rates of MB exceeded 96% after 5 cycles of photoelectrocatalytic experiments. Free radical quenching experiments indicated that superoxide radicals were the main active groups during the photoelectrocatalysis. Additionally, the mechanism of photocatalytic degradation for MB under the electric field was briefly analyzed. This study will provide technical support for the photoelectrocatalytic degradation of organic dye wastewater.

Organic molecule-mediated synthesis of GdPO4:Eu3+ micro/nano-luminescent materials and MRI tracing performance evaluation

The influence of the introduction of structural modifiers citric acid and acetic acid on the morphology, luminescence properties and magnetic resonance imaging (MRI) tracer properties of GdPO4:Eu3+ micronanoparticles synthesized in ethanol system was investigated in the paper. In this system, GdPO4:Eu3+ micronanomaterials such as square flake, hexagram, waist drum morphologies can be prepared by adjusting ratios of structural modifier, phosphoric acid and gadolinium nitrate, respectively. In addition, the synthesized products were analyzed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), fluorescence spectroscopy (PL), and magnetic resonance imaging (MRI) detection. The products were found to exhibit good crystallinity, particularly in terms of their luminescent properties, which exhibited notable differences. Overall, the luminescent properties of GdPO4:Eu3+ synthesized by citric acid modification were significantly enhanced compared with acetate modification, with at least five times more luminescent intensity than that of acetate modification. And amazingly, the GdPO4:Eu3+ luminescence intensity is strongest when the square flake-hexagram coexisting. The tracer properties of GdPO4:Eu3+ MRI with better luminescent square flake, hexagram, and square flake-hexagram coexisting morphologies were also investigated. It was found that the square flake had better T1-longitudinal relaxation imaging with a relaxation rate r1 value of 0.79 mM−1s−1. This work is a good advancement for organic molecule-mediated modulation, synthesis of gadolinium phosphate-based rare-earth micronanomaterials and study of their applications in luminescence and MRI tracing.

Synthesis and characterization of new organometallic lanthanides metal complexes for photodynamic therapy

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{10}^{6}$$\\end{document} M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable.

Evaluation of AlN insertion layer on the properties of heterogeneous integrated Ga2O3 films on sapphire

Integration of gallium oxide (Ga2O3) with highly thermal conductive AlN/sapphire substrate is more effective to dissipate heat in the Ga2O3-based devices. In this work, the properties of Ga2O3 films grown on sapphire and AlN/sapphire substrates via MOCVD were both examined via various experimental methods. The X-ray diffraction (XRD) analysis showed good crystallinity and different orientations of Ga2O3 and AlN thin films. The absorption properties and band gaps were extracted from UV/Vis spectra. The atomic force microscopy (AFM) scanning images showed smooth Ga2O3 surfaces on sapphire and AlN/sapphire substrates (RMSs of 2.4 nm and 4.8 nm, respectively). The scanning electron microscopy (SEM) highlighted well-defined grains of Ga2O3 and distinct boundaries of both heterostructures. X-ray photoelectron spectroscopy (XPS) analysis depicted the distributions of various components throughout the films. Finally, by using the time-domain thermoreflectance (TDTR) method, the thermal conductivity and the thermal boundary conductivity of Ga2O3 without AlN interlayer were found to be 3.1 W/(m·K) and 70.1 MW/(m2·K) respectively. By comparison, adding AlN interlayer made the thermal conductivity and thermal boundary conductivity rise to 3.3 W/(m·K) and 111.5 MW/(m2·K) respectively. These findings have demonstrated the high-quality Ga2O3/AlN integration and good heat dissipation provided by AlN interlayer, opening up new prospects for Ga2O3/AlN devices in the future.

Dysprosium chromite nanoparticles: A promising photocatalyst for the remediation of ciprofloxacin and methylene blue from wastewater

A facile sol-gel synthesis method was employed to synthesize dysprosium chromite (DyCrO3) nanoparticles (NPs), which were subsequently calcined at 750 ∘C to investigate their structural, optical, and photocatalytic properties. Rietveld refinement of powder X-ray diffraction patterns revealed a single-phase orthorhombic structure for the DyCrO3 NPs, exhibiting good crystallinity and belonging to the Pbnm space group. Furthermore, Field Emission Scanning Electron Microscopy and Transmission Electron Microscopy imaging revealed a promising morphology with an average particle size of 30 ± 7 nm. Optical assessments indicated an energy band gap of 2.72 eV, suggesting potential for solar light harvesting as a photocatalyst. Mott-Schottky plots confirmed the n-type semiconductor behavior of the DyCrO3 NPs, and valence band X-ray photoelectron spectroscopy analysis supported these findings. Electronic band structure calculations showed a substantial conduction band minimum and a positive valence band maximum, essential for promoting oxygen reduction and oxidation reactions, respectively, which are crucial for photocatalytic activity. Moreover, the synthesized DyCrO3 NPs demonstrated significant potential as efficient photocatalysts, effectively decomposing the antibiotic ciprofloxacin (CIP) under solar light. Notably, the DyCrO3 NPs achieved 83 % degradation of CIP within 240 min of solar irradiation. Similarly, under identical conditions, the DyCrO3 NPs photocatalyst showed promise in degrading 70 % of the colored organic pollutant methylene blue (MB). Interestingly, during the first 120 min, the degradation of CIP was approximately 25 % greater than that of MB. The ability of DyCrO3 NPs to efficiently degrade both colored and colorless pollutants highlights the catalyst’s inherent photocatalytic nature, rather than merely relying on dye-sensitization effects. Furthermore, the presence of DyCrO3 NPs reduced the activation energy for CIP degradation from 31.657 kJ mol−1 K−1 to 20.846 kJ mol−1 K−1, providing additional evidence of their true catalytic efficacy. Apparent quantum yield values of 40 % for CIP and 35 % for MB degradation further illustrate their superior solar energy harvesting ability. A comprehensive mechanism was developed to explain the impressive photocatalytic performance of the synthesized NPs, highlighting their potential in degrading pharmaceutical antibiotics.

Comparative Study of Indium Oxide Films for High‐Mobility TFTs: ALD, PLD and Solution Process

AbstractDeposition of indium oxide base films for high‐mobility thin film transistors (TFTs) has been an important part in the implementation of high‐resolution and high‐frequency display back panels. In this study, three types of In2O3 (InO) films have been fabricated for TFTs using atomic layer deposition (ALD), pulsed laser deposition (PLD), and solution process, respectively. ALD‐derived InO films show controllable grain formation and optimized TFTs show the field effect mobility of ≈100 cm2 V−1s−1 in both the conventional transistor measurements and critical four‐probe measurements, reaching the level of low‐temperature polycrystalline silicon (LTPS). Combined spectroscopy investigations show that the ALD‐derived InO film features advantages as compared to those of the PLD‐deposited and solution‐processed InO film in providing a smoother surface morphology, good crystallinity, and more orderly atomic growth mode. Moreover, the bias‐stress stability of ALD‐derived TFTs can be improved with further passivation.

Influence of Substrate on Sb2Se3/CdS Heterojunction Thin Film Solar Cells and Evaluation of Their Performance by Dark J‐V Analysis

ABSTRACTA simple binary antimony selenide (Sb2Se3) absorber is evolving as an alternative photovoltaic material in thin film solar cells because of its unique properties and easy processing. Sb2Se3 thin films having good crystalline quality are grown via versatile thermal evaporation from pre‐synthesized near stoichiometric compound material on molybdenum‐coated soda lime glass (SLG) and borosilicate glass (BG) substrates. Following the systematic characterizations on the absorber films, substrate configured Sb2Se3/CdS heterojunction devices were fabricated and their photovoltaic characteristics have been studied using current density vs. voltage (J‐V), dark J‐V modeling, external quantum efficiency and capacitance vs. voltage measurements. The power conservation efficiency values of 4.88% and 5.04% were achieved for the devices fabricated on SLG and BG substrates, respectively with deficit in open circuit voltage. The obtained values are higher in comparison to the reported device efficiencies in substrate configured Sb2Se3 solar cells, in which the absorber is prepared through thermal evaporation. To understand the loss in open circuit voltage, a compact equivalent circuit model was considered and identified the contribution of different shunt leakage paths in the devices. In addition to that, the device fabricated on the SLG was stable with minimal changes in its photovoltaic performance for a period spanning over 200 days. The results obtained are encouraging with scope for improving the device performance through interface engineering and back surface passivation strategies.

Room temperature in situ growth of fluorinated covalent organic framework on electrospun nanofibers for efficient detection of benzoylurea insecticide residue in water samples

The accurate detection of benzoylurea insecticides (BUs) residues is vital for the environment and human health. In this work, a room-temperature synthesis strategy was developed to fabricate the covalent organic framework (COF)–polyacrylonitrile (PAN) nanofibers composite by an electrospinning technique. The COF was functionalized on PAN nanofibers via in situ polymerization of 1,3,5-tris(4-aminophenyl)triazine (TAPT) and 2,3,5,6-tetrafluoroterephthaldehyde (TFTA). The obtained TAPT-TFTA@PAN nanofibers showed a porous structure, high surface area, good crystallinity and excellent extraction efficiency to BUs. A sensitive method combining dispersive solid-phase extraction (DSPE) using TAPT-TFTA@PAN nanofibers as an adsorbent with liquid chromatography–ultraviolet detector was developed for trace analysis of four BUs in environment water samples. This method achieved a wide linear range of 0.5–200 ng·mL−1 for triflumuron and hexaflumuron, and of 0.5–150 ng·mL−1 for teflubenzuron and fluazuron. The limits of detection (S/N = 3) for four BUs ranged from 0.11 to 0.42 ng·mL−1. The accuracy of the proposed method was validated by measuring trace BUs in the spiked water samples with recoveries in the range of 98.3 %∼125.3 %. The results demonstrated that the TAPT-TFTA@PAN nanofibers have great potential as an extractant for effective enrichment of benzoylurea insecticide from complex water samples.

Comprehensive surface and crystallographic structure investigation of MnGaGe nanoislands grown on GaAs

The growth of islands with nanometer height and diameter sizes of the ternary compound MnGaGe with tetragonal structure on the GaAs (001) substrate surface was investigated. Topographic analyses performed by atomic and magnetic force microscopy are consistent with the formation of ferromagnetic MnGaGe nanoislands, constituted by the preferential stacking of (001) and (110) planes whose are the most favorable to the epitaxial relationship on the (001) surface of GaAs wafer, not tested yet. As the spontaneous magnetization tends to align preferentially perpendicular to the Mn basal planes of the tetragonal crystallographic structure, one part of the nanoislands has magnetic dipole or even single- domains whose magnetization is in-plane and another part out-of-plane directions, in the remanent state. Kelvin probe force microscopy and ultraviolet photoelectron spectroscopy analysis obtained the work function, not measured in the literature, and indicates the intermetallic character of the MnGaGe nanoislands, whose near-stoichiometry and good crystalline structure are confirmed by energy dispersive X-ray spectroscopy, X-ray diffraction together with nanodiffraction probe and X-ray fluorescence mapping carried out at a synchrotron installation. The high chemical stability of the MnGaGe nanoislands exhibiting ferromagnetism at room temperature with magnetization perpendicular to the substrate is very promising for spintronic applications at nanoscale.

Heat capacities and thermodynamic properties of urea phosphate and its aqueous solutions at various temperatures

Urea phosphate was produced through a complexation reaction of phosphoric acid and urea and subsequent cooling crystallization. The elemental composition analysis, XRD, and FTIR all confirmed that the prepared urea phosphate had high purity and good crystallinity, and showed a clear onset melting temperature of 118.12℃ and corresponding enthalpy change of 222.10 J∙g−1 in TG/DSC measurement. Meanwhile, the heat capacities of urea phosphate and its aqueous solution were carefully measured using microcalorimetry with an expanded relative uncertainty better than 2 %. The experimental results revealed that the heat capacity of urea phosphate rises rapidly with temperature, with an increase of 41 % from −20 to 100℃. The experimental heat capacity data were correlated with semi-empirical models of Maier-Kelley equation, Khodakovsky equation and Debye-Einstein equation which all give excellent reproduction of the measured data with very close average deviation around 0.5 %. The enthalpy, entropy, and Gibbs free energy of solid urea phosphate were estimated at various temperatures by integrating heat capacity against temperature with Maier-Kelley equation and the results confirmed urea phosphate is thermally quite stable below 100℃. The heat capacity of urea phosphate aqueous solution increases with concentration and temperature, and there is a strong linear relationship between the solution’s heat capacity and temperature when the composition remains constant. The apparent molar heat capacity of urea phosphate in solution is positive and increases with concentration and temperature. The extrapolated partial molal heat capacity of urea phosphate is temperature independent and shows an average value of −709.4 J·K−1·mol−1. Due to the partial dissociation and partial ionization of urea phosphate in solution, the excess molar heat capacities show positive deviation from that of ideal solution, which also increases with the increase of concentration and temperature.

Structural and Electrochemical Properties of Binary ZnO:Al Nanocomposites as Anode for Lithium-ion Batteries

In conventional lithium-ion batteries (LIBs), carbon compounds are commonly utilised as the anode owing to their great performance, low cost, and abundance. However, due to the limited storage capability of pure carbon materials that restrict further improvement of LIBs, zinc oxide (ZnO) has been one of the promising anode materials to be used as an alternative to strengthen the electrochemical performance of LIBs due to its high theoretical capacity of 987 mAh g-1. This study aims to synthesise ZnO:Al nanowires using the hot-tube thermal evaporation method. Three types of samples are made using this method by varying the concentration of 0 wt% (S1), 3wt% (S2), and 6 wt% (S3) of aluminium (Al) during the Al deposition process. The EDX findings indicated that the sample has a high proportion of zinc (Zn) and oxygen (O), with the S3 sample having the highest Al concentration after being deposited. The most substantial diffraction peak for XRD of all samples was found at (101), exhibiting a single crystalline hexagonal structure with optimum growth direction on the c-axis. For EIS analysis, the S3 sample has the lowest bulk resistance and maximum ionic conductivity. In conclusion, the ZnO sample with 3 wt% of Al as a dopant was selected as the optimum result to synthesise a homogenous surface of ZnO:Al with good crystallinity by using a hot-tube thermal evaporation process and giving the best conductivity in electrochemical performance.

Construction of One-Dimensional Covalent-Organic Framework Coordinated with Main Group Metals for Selective Electrochemical Synthesis of H2O2.

Covalent-organic frameworks (COFs) are promising electrocatalysts for the selective synthesis of H2O2 through the two-electron oxygen reduction reaction (2e- ORR). However, the design and synthesis of efficient and stable COF-based electrocatalysts is still challenging. In this work, a predesigned 1,10-phenanthroline-based one-dimensional COF (PYTA-PTDE-COF) was constructed to anchor main group metal (In, Sn, and Sb) as electrocatalysts toward 2e- ORR. The catalysts are featured with fully exposed metalated side chains. Structural characterization revealed that PYTA-PTDE-M's (M = In, Sn, and Sb) are all quite similar, except for the coordinated metal ions with the maintenance of good crystallinity. They all exhibited satisfying activity and selectivity toward 2e- ORR under alkaline conditions. Among them, PYTA-PTDE-Sb exhibited the best performance (Eonset is 0.765 V, the H2O2 selectivity is 96%, and the yield rate is 209.2 mmol gcat-1 h-1). Moreover, it also delivered superior stability with almost no attenuation of current density during the long-time test. Theoretical calculations revealed that the Sb metal site in the COFs has the lowest adsorption strength of *OOH, which could be the main reason for its superior selectivity. The PYTA-PTDE-Sb assembled zinc-air battery realizes not only the supply of clean energy but also the production of green chemicals, showing it is highly promising in practical applications. This work offers an example for designing main group metal-coordinated 1D COFs and reveals fundamental structure-activity relationship toward 2e- ORR.