Facile mechano-chemical synthesis and enhanced photocatalytic performance of Cu2ZnSnS4 nanopowder

In the present study, Cu₂ZnSnS₄ (CZTS) powder was synthesized by the mechano-chemical method from its elemental constituents. X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and diffusion reflectance spectroscopy (DRS) were used for characterization of structural, morphological and optical properties. XRD result confirmed that a highly crystalline CZTS phase corresponding to the kesterite structure was formed after 50 h ball milling. Raman analysis confirmed the existence of single phase CZTS without any other phases. FESEM and TEM images reveal the irregular CZTS nanoparticles with an average size of 90 nm. The elemental mapping of the CZTS nanopowder showed the uniform distribution in agreement with the stoichiometry. DRS result showed a band gap value of 1.53 eV. XPS result revealed the oxidation states as Cu⁺, Zn²⁺, Sn⁴⁺ and S²⁻. The photocatalytic activity of CZTS has been investigated through photodegradation of methylene blue (MB) and methyl orange (MO) dyes solution with different concentrations under visible light irradiation. Although the CZTS decomposed MO only 81% until 210 min, the MB solution was completely photodegraded after 100 min. A kinetic study by Langmuir-Hinshelwood (L-H) model indicated about 3.7 times faster degradation of MB than MO and also higher adsorption capacity for MB by CZTS. Furthermore, the prepared CZTS was reusable and can be repeatedly used for the removal of dyes from aqueous solutions.     

Solvothermal synthesis and characterizations of graphene-ZnBi12O20 nanocomposites for visible-light driven photocatalytic applications

The Bismuth based Zinc metal oxide (ZnBi₁₂O₂₀) nanorods were synthesized via single step solvothermal approach. The characterization of synthesized hybridized structure was done by several analysis such as X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (UVvis–DRS), Fourier transform-infrared spectroscopy (FT–IR), Thermogravimetric analysis (TGA), Raman spectroscopy, Field-Emission scanning electron microscopy (FESEM), Energy dispersive analysis of X-rays (EDX), High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy. The photocatalytic activity of ZnBi₁₂O₂₀ and an incorporation of varying weight percentages of GO (1–4 wt %) into ZnBi₁₂O₂₀ catalyst (GZBC) were analyzed under visible light irradiation by the degradation of an aqueous solution of Methylene blue (MB) and Methyl orange (MO) dye. Among various developed nanocomposites, 3 wt% GZBC reduced graphene oxide exfoliated nanocomposites has revealed the degradation efficiency as 96.04, 94.52% at 100 and 120 min for MB and MO respectively with enriched visible light absorption range. The photocatalytic property of 3 wt % reduced graphene oxide exhibits higher degradation behavior than that of other synthesized nano-composites.     

ZnO–SnO2 nanocubes for fluorescence sensing and dye degradation applications

ZnO–SnO₂ nanocubes were used as promising material for efficient sensing of p-nitrophenol and faster photocatalytic degradations of dyes like methyl orange (MO), methylene Blue (MB) and acid orange 74 (AO74). ZnO–SnO₂ nanocubes were prepared by the facile solution process at 50 °C using Zn(NO₃)₂·6H₂O and SnCl₂·2H₂O as a precursor in the presence of ethylenediammine. The synthesized material was examined for its morphological, structural, crystalline, optical, vibrational, and compositional studies by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy. FESEM studies revealed the formation of well-defined ZnO–SnO₂ nanocubes where the structural examinations revealed the formation of a crystalline tetragonal rutile phase for SnO₂ with some crystal sites doped with Zn. The as-synthesized nanocubes were explored for their photocatalytic activities towards three different dye viz. MO, MB, and AO74. Practically, complete degradation of AO74 was seen within 4 minutes of photo-irradiation in the presence of 0.05 g ZnO–SnO₂ nanocubes. However, 97.17% and 41.63% degradations were observed for MB and MO within 15 and 60 minutes, respectively. All the dye degradation processes followed the pseudo-first-order kinetic model. Moreover, the as-synthesized nanocubes were utilized to fabricate highly sensitive and selective fluorescent chemical sensor for the detection of p-nitrophenol (PNP). ZnO–SnO₂ nanocubes showed a very low detection limit of 4.09 μM for the detection of PNP as calculated according to the 3σ IUPAC criteria. Further, the as-synthesized ZnO–SnO₂ nanotubes were found to be highly selective for p-nitrophenol as compared to the other two isomers.     

Synthesis of hexagonal boron nitride fibers within two hour annealing at 500 °C and two hour growth duration at 1000 °C

Several advantageous features like low density, large surface area, high porosity and tight pore size make the nanofiber suitable for a wide range of applications from medical to consumer products and industrial to high-tech applications. Present study concerns the synthesis of hexagonal boron nitride fibers (Ø=70–350 nm) from a mixture of Boron, Magnesium oxide and Iron oxide powders via a simple CVD technique. A relatively long annealing and growth duration of two hours at 500 °C and 1000 °C, respectively were utilized in this synthesis. The synthesized samples seem to have the BNFs of irregular curved human hair-like morphologies in lower resolution and solid cylinder-like structures in high resolution transmission electron microscopy. The presence of Boron and Nitrogen in the synthesized BNF's sample were confirmed via the B 1s peak at 190.7 eV and N 1s peak at 398.3 eV in the XPS survey whereas a major peak at 1370 (cm⁻¹) in the Raman spectrum corresponds to the vibration of E_2g mode in h-BN. The sharp peaks in the XRD pattern verify the h-BN phase and highly crystalline nature of the synthesized BNFs.     

Magnetic characteristics and optical band alignments of rare earth (Sm+3, Nd+3) doped garnet ferrite nanoparticles (NPs)

Yttrium iron garnet (YIG) nanoparticles (NPs) doped with rare earth (RE) metal ions (Y_2.5Sm_0.5Fe₅O₁₂, Y_2.5Nd_0.5Fe₅O₁₂) were successfully synthesized by sol-gel auto combustion approach. The cubic crystalline structure and morphology of the prepared garnet ferrite NPs were analyzed by X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The cubic crystalline garnet phase of the synthesized YIG, Sm-YIG and Nd-YIG samples was successfully achieved at 950 °C sintering temperature. The force constant and absorption bands were estimated by using Fourier transform infrared spectroscopy (FTIR). The doping effect of RE metal ions on the chemical states of YIG were examined by x-ray photoelectron microscopy (XPS). The valence band (from 12.63 eV to 13.22 eV), conduction band (from 10.89 eV to 11.34 eV) edges and optical bandgap values of RE doped YIG samples were calculated using UV–Vis spectroscopy and ultraviolet photo electron spectroscopy (UPS). The magnetic analysis of the prepared NPs was studied using vibrating sample magnetometer (VSM). The XPS analysis of RE doped YIG samples exhibit the existence of RE (Sm⁺³, Nd⁺³) contents on the surface of YIG ferrite by decreasing the oxygen lattice in garnet structure. The optical bandgap (from 1.74 eV to 1.88 eV) explains the semiconducting nature of the synthesized NPs. The UPS results confirm the valence band position of YIG doped samples. The saturation magnetization and remanence of RE doped garnet ferrite samples increased from 13.45 to 18.83 emu/g and 4.06–6.53 emu/g, respectively.     

Morphological,structural, surface,thermal, chemical,and magnetic properties of Al-doped nanostructured copper ferrites

Aluminum-doped copper ferrite nanoparticles synthesized via thermal decomposition were analyzed for Al³⁺ substitution effects. Nanocrystalline doped copper ferrite with a crystallite size <9 nm was characterized using several advanced techniques, including X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The degree of thermal decomposition used for doping copper ferrite at the nanoparticle level correlates well with the quantitative, dimensional, and structural characterizations. The Scherrer equation and Williamson–Hall method were employed to determine the general lattice strain and constants. Structural properties, such as the oxygen positional parameters, radii of the octahedral and tetrahedral sites, hopping lengths, bond lengths and angles, site bonds, and edge lengths, were determined using XRD patterns. The improved A–B super-exchange interaction was demonstrated by the discrepancy in the theoretically anticipated bond angles. The analysis of magnetic hysteresis (M − H) using a vibrating sample magnetometer (VSM) and XPS confirmed the improvement in the super-exchange interaction. XPS results suggest that Fe and Cu in the crystal lattice are in the form of Fe^III and Cu^II, respectively. The investigation of the degree of inversion, state, and composition using XPS aids to understand the properties of the nanostructured copper ferrites. The saturation and remnant magnetization were determined from hysteresis loops at 1.8 T obtained using the VSM at room temperature. The noncollinear spin and efficient sublattice interactions are responsible for the decrease in M_s and M_r.     

Ternary Ag@SrTiO3@CNT plasmonic nanocomposites for the efficient photodegradation of organic dyes under the visible light irradiation

In this research, carbon nanotube (CNT)-modified plasmonic silver-strontium titanate (Ag@ SrTiO₃) nanocomposites for the degradation of the organic dye were prepared by the sol-gel method. The characterization of all products was carried out using the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N₂ adsorption-desorption test (BET), field emission-scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS), and transient photocurrent (TPC) studies. It was found that the incorporation of Ag in and introducing CNT into the SrTiO₃ nanoparticles reduced the crystallite size to 21 nm and the band gap energy to 2.7 eV. The Reduced PL peak intensity, increased photocurrent value, and reduced charge transfer resistance approved that the Ag@SrTiO₃@CNT nanocomposite had a greater charge transfer efficiency than other samples. The optimal dosage of the photocatalyst, for the complete degradation of 5 ppm of the methylene blue (MB) solution after 30 min of the visible light irradiation, was decided as 0.5 g/L. Besides, in the experimental environment, the Ag@SrTiO₃@CNT sample illustrated the most significant photocatalytic performance of the degradation of methyl orange (MO) and Rhodamine B (RhB) dyes. The detailed mechanism and kinetics of the degradation procedure were clarified. Finally, the prepared system displayed increased stability and reusability in the entire cyclic degradation experiment.     

Preparation,microstructure and ion-irradiation damage behavior of Al4SiC4-added SiC ceramics

Single-phase Al₄SiC₄ powder with a low neutron absorption cross section was synthesized and mixed with SiC powder to fabricate highly densified SiC ceramics by hot pressing. The densification of SiC ceramics was greatly improved by the decomposition of Al₄SiC₄ and the formation of aluminosilicate liquid phase during the sintering process. The resulting SiC ceramics were composed of fine equiaxed grains with an average grain size of 2.0 μm and exhibited excellent mechanical properties in terms of a high flexure strength of 593 ± 55 MPa and a fracture toughness of 6.9 ± 0.2 MPa m^1/2. Furthermore, the ion-irradiation damage in SiC ceramics was investigated by irradiating with 1.2 MeV Si⁵⁺ ions at 650 °C using a fluence of 1.1 × 10¹⁶ ions/cm², which corresponds to 6.3 displacements per atom (dpa). The evolution of the microstructure was investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The breaking of Si–C bonds and the segregation of C elements on the irradiated surface was revealed by XPS, whereas the formation of Si–Si and C–C homonuclear bonds within the Si–C network of SiC grains was detected by Raman spectroscopy.     

Influence of the concentration of capping agent on synthesizing and analyses of Ceria nano-filler using modified co-precipitation technique

The pure crystalline cerium oxide (CeO₂) nanoparticles were synthesized using optimized content of Ce(NO₃)₃. 6H₂O with varying concentrations of sodium hydroxide (NaOH) (0.5, 1, 1.5, and 2 M) as a precipitation agent in presence of 2.5 wt% poly(vinylpyrrolidone) PVP. All the samples are prepared via the modified coprecipitation technique. The synthesized materials have been analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), laser Raman, high-resolution scanning electron microscope (HR-SEM), and photo luminescence (PL) analyses. The optimized sample was identified with the help of the above studies that could be analyzed through transverse electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies. The cubic structure with the Fm-3 m space group has been confirmed through XRD (JCPDS: 81-0792) and Raman analyses. The FT-IR and energy dispersive X-ray spectroscopy (EDX) analyses ascertain the occurrence of Ce and O species. The as-prepared CeO₂ filler (0, 3, 6, 9, and 12 wt%) is dispersed through the optimized polymer electrolyte Poly (styrene-co-methyl methacrylate) P(S-MMA) (27 wt%)–lithium perchloride (LiClO₄) (8 wt%)–ethylene carbonate + propylene carbonate (EC + PC) (1;1 of 65 wt%) complex system using solution casting technique. P(S-MMA) (27 wt%)–LiClO₄ (8 wt%)–EC + PC (1;1 of 65 wt%)–6 wt% of CeO₂ shows the high ionic conductivity 8.13 × 10⁻⁴ S cm⁻¹.     

Effective synthesis of well graphitized high yield bamboo-like multi-walled carbon nanotubes on copper loaded α-alumina nanoparticles

A high-yield bamboo like multiwalled carbon nanotubes (CNTs) were successfully synthesized on copper substituted alumina nanoparticles by thermal chemical vapor deposition (CVD) technique under atmospheric pressure. The obtained products were characterized by various techniques like FESEM with EDX, HRTEM and Raman spectroscopy, which reveals the formation of CNTs and are of bamboo shaped (stacking arrangement) multiwalled type with graphene layers having a diameter between 4 and 9 nm. The appearance of two peaks at 1597 cm^− 1 and 1302 cm^− 1 in Raman spectra are noticed as G-band and D-band for graphitic nature and defects due to bending & curvature of bamboo like carbon nanotubes (b-CNTs), respectively. The influence of reaction parameters such as time, temperature and flow rate was also studied to increase the carbon yield.     

Corrosion behavior of pulse laser deposited 2D nanostructured coating prepared by self-made h-BN target in salinity environment

Hexagonal boron nitride (h-BN) target was prepared by two step wet chemical reaction method using a nontoxic starting materials (urea and boric acid). Optimized annealing parameters (1600 °C for 2 h) and N₂ environment are applied for pertinent growth of boron nitride nano powder. A mechanical procedure was acquired to convert this powder into pallet (target) for further analysis. The prepared target (white pallet) was used to fabricate the corrosion resisting h-BN nano-sheet coating using pulse laser deposition technique. A thick h-BN coating was deposited on SS 304 and Si substrates. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to characterize the coating for structural and morphological purpose. X-ray photoelectron spectroscopy (XPS), Atomic force microscopy (AFM), and energy-dispersive X-ray spectroscopy (EDXA) were employed to characterize the coating for surface properties and chemical composition purpose. However, Contact angle and electrochemical work station were employed for wetting and corrosion analysis tests. We find that pulsed laser deposition (PLD) grown h-BN coating shows the non-wetting (134.2°) and reduce corrosion rate by one order of magnitude compared to bare SS. On the basis of these results, the h-BN nano-sheet coating may be a promising candidate for corrosion resist application in (3.5% NaCl solution) salinity environment.     

One pot synthesis of multiwalled carbon nanotubes reinforced polybenzimidazole hybrids: Preparation,characterization and properties

Poly[2,2^′-(p-oxydiphenylene)-5,5^′-bibenzimidazole] (OPBI) nanocomposites containing 0.1–1 wt% multi wall carbon nanotubes (MWNTs) have been synthesized via “one pot synthesis” which combines the in situ modification of MWNTs and in situ polymerization of OPBI in one reaction pot, a technique that is particularly suitable for large scale production. Raman spectroscopy, NMR, XPS and XRD characterizations of OPBI grafted MWNTs (MWNT-g-OPBI), purified from the MWNT-g-OPBI/OPBI hybrid, reveal that the OPBI chains are successfully attached to the surface of MWNTs in the process of one pot synthesis method. Fracture morphology of the nanocomposites reveals very efficient distribution of the MWNTs within the OPBI matrix with good interfacial interaction. The mechanical properties (including tensile and yield strength, Young's modulus, etc.) are obviously increased even at 0.1 wt% MWNTs loading, and further improvement is observed at higher filler contents. The thermal stability and electrical conductivity are also improved with the incorporation of MWNTs.     

Hydrogen incorporation,bonding and stability in nanocrystalline diamond films

The hydrogen concentration in hot filament and microwave plasma CVD nanocrystalline diamond films is analysed by secondary ion mass spectrometry and compared to the film grain size. The surface and bulk film carbon bonds are analysed respectively by X-ray photoelectron spectroscopy (XPS) and ultra-violet Raman spectroscopy. XPS results show the presence of the hydrogenated p-type surface conductive layer. The respective intensities of the 1332 cm^− 1 diamond peak, of the G and D bands related to sp² phases, and of the 3000 cm^− 1 CH_x stretching mode band, are compared on Raman spectra. The samples are submitted to thermal annealing under ultra-high vacuum in order to get hydrogen out-diffusion. XPS analysis shows the surface desorption of hydrogen. Thermal annealing modifies the sp² phase structure as hydrogen out diffuses.     

Engineering of morphological,optical, structural,photocatalytic and catalytic properties of nanostructured CuO thin films fabricated by reactive DC magnetron sputtering

Nanostructured thin films of CuO were deposited on silica glass substrates using reactive DC magnetron sputtering technique. Microstructural, morphological, optical, catalytic and photocatalytic properties of the prepared CuO thin films were examined using FESEM, AFM, Rutherford backscattering spectrometry, XRD, XPS, UV–Vis absorption and PL spectroscopy. FESEM showed nanostructures in the thin films, which were confirmed to be of monoclinic CuO by XRD analysis. Substrate temperature variation (40 °C, 100 °C and 300 °C) was found to significantly alter the optical, morphological, photocatalytic and structural properties of the CuO nanostructured thin film coatings. FESEM and AFM analyses showed decrease in size of nanostructures and surface roughness increase with increase in substrate temperature. Increase in UV–Vis absorbance and PL intensity of CuO thin films with decrease in crystallite size were noticed as the substrate temperature was increased. The prepared nanostructured CuO thin films exhibited highly enhanced photocatalytic activities and degraded dyes (MB and MO) in water in just 40 min under solar exposure and catalytic transformation of 4-nitrophenol (4-NP) took place in just 15 min. The developed CuO nanostructured thin film coatings are very promising for large scale, practical and advanced catalytic reduction of toxic 4-NP and photocatalytic applications in solar driven water purification.     

Synthesis of sponge like Gd3+ doped vanadium oxide/2D MXene composites for improved degradation of industrial effluents and pathogens

Current report is based on the synthesis of Gd⁺³ doped V₂O₅ nanostructures (GVO) along with fabrication of GVO/MXene binary nanocomposite. As synthesized GVO and GVO/MXene were characterized by XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Energy dispersive X-ray), BET (Brunauer Emmett Teller technique) and UV–Visible spectroscopy. Diffraction and elemental analysis confirmed the substitution of Gd⁺³ ions in VO layers. Orthorhombic phase of VO was observed in both GVO and GVO/MXene samples with crystallite size range of 17.02–17.51 nm. FESEM analysis indicated asymmetrical VO particles and sheets distributed on MXene layers, giving out a sponge like appearance. Surface area of GVO and GVO/MXene was enhanced to 20.46 and 23.69 nm, respectively. Effect of Gd⁺³ contents was significant on optical properties, which reduced the band gap energy of VO to 2.33 eV. The photocatalytic performance of prepared samples was analysed by the degradation of Methylene blue (MB) under direct sunlight. Gd⁺³ ion doping was found useful to enhance degradation of MB up to ～71%. Among all samples, GVO/MXene showed maximum degradation (～92%) within 120 min. Meanwhile, GVO/MXene showed good recyclability for successive five cycles. In addition, GVO and GVO/MXene were effective antibacterial agents against Gram positive (S. aureus) and Gram negative (P. vulgaris) strains of bacteria. The results suggested that the GVO and GVO/MXene could serve as potential candidates for large scale treatment of organic pollutants and pathogens.     

Thermal conductivity and mechanical properties of thermally conductive composites based on multifunctional epoxyorganosiloxanes and hexagonal boron nitride

As electronics become portable and compact with concomitant thermal issues, the demand for high-performance thermal interface materials has increased. However, the low thermal conductivity of polymers and the poor dispersion of fillers impede the realization of high filler loading composites, and this in turn limits the increase in thermal conductivity. To overcome this, multifunctional epoxyorganosiloxanes (MEOSs) were synthesized and used to fabricate thermally conductive composites in this study. In the first part of this study, the effect of the molecular weights of MEOSs on the curing behaviors of the MEOSs/trimethylolpropane tris(3-mercaptopropioante)/1-methyl imidazole systems was investigated by a DSC analysis. Both the nonisothermal and isothermal curing of the epoxy compositions (ECs) verified that the reaction rate of EC-1 containing MEOS-1 with lower molecular weight was faster than that of EC-2. In addition, mechanical properties of the cured EC-1 were superior to those of its counterpart because of a higher density in crosslinking. In the second part, EC-1 was admixed with h-BN to fabricate thermally conductive (TC) composites. Owing to the low viscosity (1.6 Pa s at 0.1 Hz) of EC-1, a TC-3 composite containing 45 wt% h-BN fillers was obtained, and the in-plane and through-plane thermal conductivity of the cured TC-3 composite reached 3.55 ± 0.29 Wm^?1K^?1 and 1.08 ± 0.08 Wm^?1K^?1, respectively. Furthermore, the tensile modulus of the cured TC-3 was measured as 76.3 ± 6.1 MPa, which was 9.1 times higher than that of the cured EC-1. Both the high thermal conductivity and good mechanical properties of the cured TC-3 composite were ascribed to the percolation of h-BN networks stemming from the high filler loading.     

Sonocatalysis and Photocatalysis in Ba0.5Sr0.5TiO3 ceramics

The photocatalytic, sonocatalytic, and sono-photocatalytic performances of Ba_0.5Sr_0.5TiO₃ (BST) ceramic (synthesized through solid-state reaction route) were investigated for the degradation of an organic dye named methylene blue (MB). The as-prepared BST ceramic powder was characterized using a scanning electron microscope, X-ray diffraction, X-ray photoelectron, and Raman spectroscopy techniques. The optical energy band gap of BST ceramic was found to be ∼3.17 eV. BST has shown significant catalytic activity following sonocatalysis and photocatalysis processes, i.e, ∼48% and ∼65% in 3 h, respectively. The synergic effect of the sonocatalysis and photocatalysis processes had shown an excellent degradation of 81% in 3 h. To determine the reactive species responsible for the degradation of MB dye, a scavenger test was also performed using isopropyl alcohol (IPA), ethylenediaminetetraacetic acid (EDTA), and benzoquinone (BQ) scavengers. The degree of MB dye degradation was quantified by a phytotoxicity test on “Vigna radiata” seeds. Furthermore, the potentiality of BST ceramic was explored for water cleaning applications while irradiating it to solar radiation in real-time conditions.     

Morphological,mechanical, and biological evolution of pure hydroxyapatite and its composites with titanium carbide for biomedical applications

Pure hydroxyapatite (HAp) was synthesized successfully via a wet chemical precipitation method. To study the influence of TiC (weight % of 5, 10, 15) substitution on the mechanical behavior of pure HAp, its composites with TiC were synthesized using a solid-state reaction method. Herein, detailed investigations of pure HAp and its composites using X-ray powder diffraction (XRD), FTIR spectroscopy, Raman spectroscopy, UV-VIS spectroscopy, SEM followed by EDAX and particle size analysis were carried out. XRD study reveals the phase stability of the prepared HAp and composite samples. However, FTIR and Raman spectroscopic studies revealed the bond formation among the various constituents. Mechanical behavior of HAp, and its composites with TiC were studied using numerous parameters like density, Young's modulus, fracture toughness, and load absorption capability. Based on these studies, it was revealed that the addition of 5 wt % substitution of TiC sintered at 1200 °C significantly enhanced the mechanical properties of pure HAp. Hence, 5 wt % of TiC composite 95HAp-5TiC showed the best mechanical characteristics such as density (2.3060 g/cm³), Young's modulus (14.53 MPa), fracture toughness (19.82 MPa m^1/2), maximum compressive strength (186 MPa) respectively. Cytotoxicity and osteogenic activities of the synthesized pure HAp and its composite, 95HAp-5TiC were performed using osteoblast cells (mouse calvarial) at different concentrations of the samples (0.01 μg, - 100 μg). From the above studies, the cell viability and ALP activities of the composite, 95HAp-5TiC found to be excellent than that of pure HAp. Hence, this composite sample may be utilized for bone implant applications.     

Preparation of nanostructure CuO/ZnO mixed oxide by sol–gel thermal decomposition of a CuCO3 and ZnCO3: TG,DTG, XRD,FESEM and DRS investigations

Nanostructure CuO/ZnO mixed oxide was systematically prepared via the sol–gel route using zinc and copper carbonates as precursors (molar ratio of 2:1) under thermal decomposition. The zinc and copper carbonates precursors have been synthesized by a simple chemical reaction in high yield and characterized by its melting point, FT-IR and thermal analysis (TG/DTG). The TG/DTG analysis proved that the thermal decomposition of zinc and copper carbonates precursors at 255 °C and 289 °C respectively. Thermo-gravimetric analysis (TG-DTG), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and diffuse reflectance spectroscopy (DRS) studies were undertaken to investigate the thermal properties and electronic structure of the CuO/ZnO mixed oxide catalysts. XRD data of the samples proved the formation of the nano-crystalline CuO/ZnO mixed oxide. Scanning electron microscopy (SEM) showed that the spherical-like particles have a diameter in the range 35–45 nm. Optical spectra of the nanostructure show a band peaked at 1.35 eV which is associated to near band gap transitions of CuO and a band centered at about 3.00 eV related to band gap transitions of ZnO nanostructures.     

Thermodynamic and microstructural analyses of photocatalytic TiO2 from the anodization of biomedical-grade Ti6Al4V in phosphoric acid or sulfuric acid

TiO₂ coatings were fabricated by anodization of Ti6Al4V in 1 M H₃PO₄ or H₂SO₄, at room temperature at 120 V for 10 min, and followed by annealing at 300° or 500 °C for 8 h. Analyses include mineralogy (GAXRD, Raman), chemistry (XPS), morphology and microstructure (FESEM, FIB, 3D confocal microscopy), thermodynamic, optical (UV–Vis), and photocatalytic performance (MB degradation). The present work highlights factors that govern the nature of the materials and their performance. The influence of the oxidation strength of the acid is pervasive in that it impacts on the crystallinity, microstructural homogeneity, coating thickness, Ti³⁺ concentration, gas generation during arcing to form pores, and resultant pore size and distribution density. A key observation is that the pores form a subsurface network of variable continuity, which has a significant impact on the surface area and associated density of photocatalytically active sites, access by liquids and gases inside the coating, penetration depth of incident radiation, gas condensation, and residual liquid trapping. These data and the related thermodynamic analyses of the acids, anodization processes, and oxidation processes facilitate the generation of schematic models for the anodization mechanisms and the resultant surface, bulk, and microstructural effects that dominate the photocatalytic performance.