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Chemical precipitation method was used to prepare of Zn0.96Ni0.04S nanoparticles. XRD showed that ZnS:Ni2+ nanoparticles crystallized in zinc blend structure with preferential orientation by the side of (111) plane. Scanning electron microscope (SEM) images of Zn0.96Ni0.04S nanoparticles portray substantial agglomeration of particles with potholed spherical morphology and energy dispersive spectrum (EDAX) measurements incorrigible that the presence of Ni in ZnS lattice. High resolution tunneling electron microscope (HRTEM) divulge that Zn0.96Ni0.04S particle size were ranges from ∼ 15 to 20 nm with good crystalline character and SAED pattern were good concurrence with X-ray diffractive (XRD) results. UV–Vis spectroscopy was engage to evaluate optical band gap of Zn0.96Ni0.04S nanoparticle, and which further disclose that when 3-mercaptopropionic (MPA) concentration increase guide the absorption edge shifted to lower wavelength. Peak at 411 °C with matching weight loss of 39.2 wt% in DTA reveals that Ni2+ ions are get away from the ZnS matrix. [ABSTRACT FROM AUTHOR]

Advancing inverted (p‐i‐n) perovskite solar cells (PSCs) is critical for commercial applications given their compatibility with different bottom cells for tandem photovoltaics, low‐temperature processability (≤100 °C), and promising operational stability. Although inverted PSCs have achieved an efficiency of over 25 % using doped or expensive organic hole transport materials (HTMs), their synthesis cost and stability still cannot meet the requirements for their commercialization. Recently, dopant‐free and low‐cost non‐stoichiometric nickel oxide nanocrystals (NiOx NCs) have been extensively studied as a low‐cost and effective HTM in perovskite optoelectronics. In this minireview, we summarize the synthesis and surface‐functionalization methods of NiOx NCs. Then, the applications of NiOx NCs in other perovskite optoelectronics beyond photovoltaics are discussed. Finally, we provide a perspective for the future development of NiOx NCs for the commercialization of perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

Advancing inverted (p‐i‐n) perovskite solar cells (PSCs) is critical for commercial applications given their compatibility with different bottom cells for tandem photovoltaics, low‐temperature processability (≤100 °C), and promising operational stability. Although inverted PSCs have achieved an efficiency of over 25 % using doped or expensive organic hole transport materials (HTMs), their synthesis cost and stability still cannot meet the requirements for their commercialization. Recently, dopant‐free and low‐cost non‐stoichiometric nickel oxide nanocrystals (NiOx NCs) have been extensively studied as a low‐cost and effective HTM in perovskite optoelectronics. In this minireview, we summarize the synthesis and surface‐functionalization methods of NiOx NCs. Then, the applications of NiOx NCs in other perovskite optoelectronics beyond photovoltaics are discussed. Finally, we provide a perspective for the future development of NiOx NCs for the commercialization of perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

In order to obtain up-conversion luminescent materials with bright red emission, a series of Yb3+, Er3+, Mn2+- doped Gd2O3 microcrystals were prepared by simple chemical precipitation method, and their morphology, structure and luminescent properties were characterized. The results show that Gd2O3 :10%Yb3+, 1% Er3+ microcrystals exhibit a flower-like morphology, and the average diameter is 2. 28 μm. After calcination at high temperature, the sample presents a cubic Gd2O3 structure with good crystallinity, and Mn2+ doping does not affect the morphology and crystal phase of the product. Under 980 nm near-infrared light excitation, Gd2O3 : 10% Yb3+, 1% Er3+ microcrystals show orange-red luminescence, which corresponds to the 4F9/2→4I15/2 transition of Er3+. With the increase of Mn2+ doping concentration (molar fraction), the luminescence intensity of Gd2O3:10% Yb3+, 1% Er3+, x% Mn2+ microcrystals first increases and then decreases, and the luminescence color gradually turns to red, which is consistent with the CIE color coordinate. At the same time, the up-conversion luminescence mechanism and the possible energy transfer process of Gd2O3: 10% Yb3+, 1% Er3+, x% Mn2+ microcrystals were analyzed according to the relationship between luminescence intensity and excitation power. [ABSTRACT FROM AUTHOR]

Photocatalysis is the most environmentally benign and efficient method for degrading organic dyes in water purification. Herein, the synthesis of ZnO nanoparticles was achieved by simple homogeneous chemical precipitation via the support of adipic acid and followed the calcination process at elevated temperatures. Based on the physical and morphological characterization analysis, the high crystallinity hexagonal structure with uniform granular shape morphology of the ZnO nanoparticles was formed with a band gap of 3.2 eV. The photocatalytic performance of the ZnO nanoparticles was investigated with the degradation of methylene blue (M.B.) dye as a model compound in an aqueous medium under UV light irradiation. The optimal ZnO‐700 nanoparticles demonstrated the highest photocatalytic activity thanks to their large surface area and numerous oxygen vacancies. More importantly, a small amount of photocatalyst (0.4 g/L) successfully degraded M.B. dye from an aqueous solution with 100 % efficiency within just 11 minutes of irradiation time under UV light with protective photocatalytic activity 4 sequential cycles. Besides, in‐depth photocatalysis experiments present that via a facile two‐step synthesis method, the as‐prepared ZnO photocatalysts depict enhanced chemical stability in a harsh environment and efficient photodegradation. [ABSTRACT FROM AUTHOR]

In the current study, the combined anti-tumor efficacy of bioactive hydroxyapatite nano- particles (HA-NPs) loaded with altretamine (ALT) was evaluated. The well-known fact that HA has great biological compatibility was confirmed through the findings of the hemolytic experiments and a maximum IC50 value seen in the MTT testing. The preparation of HA-NPs was performed using the chemical precipitation process. An in vitro release investigation was conducted, and the results demonstrated the sustained drug release of the altretamine-loaded hydroxyapatite nanoparticles (ALT-HA-NPs). Studies using the JURKAT E6.1 cell lines MTT assay, and cell uptake, as well as in vivo pharmacokinetic tests using Wistar rats demonstrated that the ALT-HA-NPs were easily absorbed by the cells. A putative synergism between the action of the Ca2+ ions and the anticancer drug obtained from the carrier was indicated by the fact that the ALT-HA-NPs displayed cytotoxicity comparable to the free ALT at 1/10th of the ALT concentration. It has been suggested that a rise in intracellular Ca2+ ions causes cells to undergo apoptosis. Ehrlich's ascites model in Balb/c mice showed comparable synergistic efficacy in a tumor regression trial. While the ALT-HA-NPs were able to shrink the tumor size by six times, the free ALT was only able to reduce the tumor volume by half. [ABSTRACT FROM AUTHOR]

In the present work, pure and Sn-doped CeO2 nanoparticles (NPs) were synthesized by the chemical precipitation method calcined at 400 °C for 4 h. Characterization of NPs was done through X-ray diffraction (XRD), UV-visible, photoluminescence (PL), Fourier transform infrared (FTIR) spectroscopy and high-resolution electron microscope (HRTEM) techniques. The XRD study revealed the crystalline nature, size, and structure of the prepared NPs. The HRTEM results illustrated cubic structure. The UV-visible and PL studies were used to measure the optical behaviors of CeO2 NPs. The UV-visible showed that the bandgap value of CeO2 NPs increased from 3.61 to 3.65 eV for different doping concentrations. The XRD study exhibited that the size of the CeO2 NPs reduced from 11.03 to 7.91 nm. From the TEM analysis, the average size of undoped and 10% Sn-doped CeO2 NPs was calculated as 9.3 and 7 nm, respectively. A cyclic voltammetric study confirmed that Sn-doped CeO2 exhibited a higher specific capacitance value than the pure CeO2. The chemical precipitation method observed excellent redox and oxidation behavior were observed for Sn-CeO2 NPs by the cyclic voltammetric study. The significant enhancement in the specific capacitance suggested that Sn-doped CeO2 is a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Co3O4 nanoparticles were purified and modified using chemical precipitation procedures, and doped with Ni, CuNi, and CdNi. The X-ray diffraction study showed that the nanoparticles had a crystallite size of 18 nm and had a cubic crystalline structure. Subsequent doping with nickel, copper–nickel, and cadmium-nickel was conducted to study the modification in the quantum state of the material, specifically examining changes in crystallite size, band gap, and magnetic characteristics. Ni(0.06)Co3O4(0.94) and Cu(0.03)Ni(0.03)Co3O4(0.94) versions showed higher optical band gaps, smaller crystallite sizes, and worse magnetic characteristics compared to undoped CoNPs. The sample Cd(0.03)Ni(0.03)Co3O4(0.94) stood out due to its exceptional magnetic characteristics. Energy Dispersive X-ray Spectroscopy was used to analyze the elemental composition of pure and doped CoNPs. Scanning electron microscopy was employed to examine the morphology, showing that the particles were mostly semi-spherical and had an average size of 32 nm. The nanoparticles’ photocatalytic degradation efficiency was evaluated by measuring the breakdown of Congo red dye in water under exposure to both a Xenon lamp and direct sunlight. This evaluation aims to measure the efficiency of photocatalytic degradation. The doped nanoparticles showed improved degradation abilities, with Cd(0.03)Ni(0.03)Co3O4(0.94) having a high degradation efficiency of 93.4% after 90 min of Xenon radiation. The efficiency was much higher than Cu(0.03)Ni(0.03)Co3O4(0.94) (80.9%), Ni(0.06)Co3O4(0.94) (68.2%), and undoped CoNPs (54%). The photodegradation rate constant for Cd(0.03)Ni(0.03)Co3O4(0.94) is equal to 22.71 × 10−3 S−1 about more than two times of pure CoNPs sample (10.20 × 10−3 S−1), these observation due to the presence of Cd and Ni doping, which have a substantial amount of surface area, and extremely small particle size, this sample was able to attain an optimal bandgap configuration, resulting in an increase in its photocatalytic performance. The photodegradation efficacy of five distinct effluent wastewaters under solar irradiation was meticulously examined. In addition, investigations were conducted into the recycling capabilities of Congo Red dye and effluent wastewater, with the processes being repeated seven and eight times, respectively, to evaluate the sustainability and efficiency of these methodologies in contaminant removal. [ABSTRACT FROM AUTHOR]

Herein we describe an effective route for the degradation of methyl green (MG) dye under visible light illumination by pristine and strontium (Sr)-doped zinc oxide (ZnO) photocatalysts (synthesized by the simple chemical precipitation method). The x-ray diffraction structural analysis has confirmed that both photocatalysts exhibit the hexagonal wurtzite structure; without any additional phase formation in Sr-doped ZnO, in particular. The optical properties of the synthesized photocatalysts have been investigated using UVâ€"vis absorption spectroscopy in the wavelength range of 250â€"800 nm. Through Tauc’s plot, the slight decrease from 3.3 to 3.2 eV in band gap energy has been elucidated (in the case of Sr-doped ZnO), which has been further confirmed by the quenching in the intensity of Photoluminescence (PL) emission spectrum. This may be due to sub-band level formation between valence and conduction band, caused by the impregnation of Sr2+ ions into ZnO host. The morphological study has also been performed using Field Emission Scanning Electron Microscope, which indicates nanoparticles (NPs) based surface texture for both photocatalysts. During the photocatalytic activity study, after 30 min irradiation of visible light, ∼65.7% and ∼84.8% photocatalytic degradation of MG dye has been achieved for pristine and Sr-doped (2 wt%) ZnO photocatalysts, respectively. The rate of photocatalytic reaction (K) has been observed to be ∼0.06399 minâˆ'1 for Sr-doped (2 wt%), whereas nearly half magnitude ∼0.03403 minâˆ'1 has been observed for pristine ZnO, respectively. The significantly improved photodegradation activity may be ascribed to the relatively broader optical absorption capability, surface defects and the enhanced charge separation efficiency of the Sr-doped ZnO photocatalyst. [ABSTRACT FROM AUTHOR]

The band-gaps of wide band gap metal sulfide semiconductors such as ZnS, are significantly reduced when doped with transition metal ions Ni2+. The new composite materials offer promising and versatile applications in spintronic devices, solar cells and other optoelectronic devices, and in photonics etc. It has led to substantial modifications in methods of synthesis for ZnS nanoparticles. In this research work, we have synthesized ZnS nanoparticles via simple chemical precipitation method. ZnS nanoparticles have been characterized using UV-visible spectra and Raman spectroscopy. For morphological studies we have used scanning electron microscopy (SEM). The optical band gap has been evaluated from UV-vis-nir absorption spectrum of the particles. Raman spectroscopy is used to study the rotational, vibrational and other modes of the sample, as we are interested to reveal properties of nanoclusters treating as those as nano-molecules. We correlate the variations in properties with their structures. Our investigations confirm formation of large single crystals (nanomolecules) yielding resonant Raman peaks. It is further confirmed from SEM images of the samples. Nanoparticles have special properties other than bulk. Their surface energy contributions are entirely different from their bulk counterparts and play dominant role in its stability. Thus, we assign a special phase for them as "Nanophase". The phenomenon of nano-cluster (aggregates) formation of nickel atoms via nucleation is also confirmed for high doping concentrations of nickel, which results into inverse trend for band-gap. [ABSTRACT FROM AUTHOR]

Nowadays, antimicrobial agents are currently being employed using noble metal nanoparticles such as gold and silver. NiO nanoparticles are a good alternative in this case, since they are less expensive than gold and silver. Antimicrobial agents are very important in textiles, water disinfection, medicine and food packaging. Most of these applications employ nanoparticles of specific shape, size and chemical composition. For these reason, present work focuses on synthesis of Nickel oxide nanoparticles by Chemical precipitation method. Obtained particles by this method were characterizes for their structural, optical, and antimicrobial properties after calcination process at various temperature of 400 °C, 600 °C, and 800 °C at 2 h. The Rietveld refinement was carried out to obtain the crystal structure and purity of synthesis was achieved. The analysis of peak broadening was performed to estimate the discrepancy in crystallite size and microstrain components of the nanoparticles with the calcination temperatures and were compared with Transmission Electron Microscope results. The calculated band gap value varies from 3.37 to 3.3 eV by increasing the calcination temperature. The emission peak at 490 and 580 nm affirmed the presence of defects in the NiO lattice. The formation of NiO was confirmed using FTIR for all the calcination at different temperatures nanoparticles. Antimicrobial activities of prepared nanoparticles were tested against selected four distinct pathogenic bacterial and three non-identical fungi species by the disc diffusion method. Results of the zone of inhibition values (mm) indicate that the test samples were exhibited significant antimicrobial activity. [ABSTRACT FROM AUTHOR]

Development photoinduced photocatalysts is a significant approach to improve photocatalytic activity and stability. Herein, we successfully prepared Zn x Cd 1 − x S / CeO 2 composites by a facile method. It is found that the Zn x Cd 1 − x S / CeO 2 composites show significant enhancement in photocatalytic activity for methyl orange (MO) degradation under visible and UV light irradiation. The degradation efficiency reaches up to 3.7 times higher than that of pure CeO 2 under visible light irradiation. Moreover, the Zn x Cd 1 − x S / CeO 2 samples have almost no loss of photocatalytic activity after five recycles, indicating good photocatalytic stability of the samples. The attractive photocatalytic activity of the Zn x Cd 1 − x S / CeO 2 samples could b e attributed to the robust charge carriers transfer and separation. [ABSTRACT FROM AUTHOR]

In this study, copper hydroxide sulfate (Cu4(OH)6SO4) was synthesized by chemical precipitation using CuSO4 as the precursor material and the first time borax as basic precipitating agent. The synthesized samples were characterized using XRD, FTIR, and SEM. The decomposition kinetics of Cu4(OH)6SO4 were examined by the thermoanalytical procedures. It was obtained from TG‐DTG data that Cu4(OH)6SO4 has two‐region decomposition at elevated temperatures. Kinetic parameters of these regions were calculated by using both the model‐fitting and model‐free methods. In the decomposition of copper hydroxy sulfate, the mean activation energy for first region was calculated as 90.88 kJ mol−1 from KAS method and 91.47 kJ mol−1 from FWO method. The mean activation energy for the second region was 207.20 kJ mol−1 from KAS and 213.34 kJ mol−1 from FWO. The activation energies for first and second regions were obtained from Ortega method as 56.3 and 198.3 kJ mol−1, respectively. [ABSTRACT FROM AUTHOR]

The aim of the present work is to investigate the change in thermal conductivity and stability of copper oxide (CuO) water-based nanofluids, which are prepared by a two-step process, with different concentrations of anionic (Sodium dodecyl sulfate SDS) and nonionic dispersants (Polyvinyl pyrrolidone PVP). Further, CuO nanofluids and nanoparticles have been characterized by XRD, EDX, FESEM, TEM, DLS, and UV to examine the particle size, elemental composition, morphology, particle size distribution, and band gap. Besides, thermal conductivity and stability of all the fluid samples have been measured with respect to particle volume fraction. The interpretation of particle stability in different weight percent of dispersants in base fluids in the presence of PVP dispersant results in a better stabilizing agent than SDS at higher particle volume fraction. Finally, evaluating the effect of lower dispersant concentration (0.1–0.5 wt%) and particle size on the thermal conductivity of CuO water-based nanofluids confirmed that the significant enhancement of thermal conductivity is observed at lower dispersant concentration and decreases with increase in particle size. The enhancement of thermal conductivity was found to be 38% and 34% at 0.4 wt% of SDS and PVP dispersants. [ABSTRACT FROM AUTHOR]

ZnO–ZnSe heterostructures were successfully synthesized by single step chemical precipitation method at room temperature. The obtained composite structures were systematically characterized for structural, morphological, optical, and vibrational properties using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), High-resolution transmission electron microscopy (HRTEM), UV–Vis DRS, photoluminescence spectroscopy (PL), and Fourier-transform Raman spectroscopy (FT-Raman). XRD patterns of the synthesized samples exhibit peaks corresponding to wurtzite ZnO and ZnSe structures which primarily confirmed the formation of single phase heterostructures. ZnO microspheres grown over the surface of ZnSe nano cauliflower clusters obtained from the FESEM images confirmed the formation of ZnO–ZnSe heterostructures. A sharp peak around 290 nm in UV–Vis DRS absorption spectra corresponds to ZnSeO3 and a wide weak absorbance is observed in the visible region (ranging from 370 to 663 nm) corresponding to the nanocomposite structure. In the Raman spectra, the surface phonon mode which is the characteristic feature of the ZnO–ZnSe heterostructures is observed at 237 cm−1. Based on the characterization results, the photocatalytic properties of ZnO–ZnSe nanoparticles were evaluated for the degradation of methylene blue (MB) and was found to exhibit solar photocatalytic property. [ABSTRACT FROM AUTHOR]

A unique method of preparing TiO2/sericite composite particles material was investigated by coating anatase TiO2 on the surface of sericite via chemical precipitation method. The results of X-ray diffraction, scanning electron microscope, infrared spectra and X-ray photoelectron spectroscopy indicated that TiO2 coated uniformly on the surface of sericite, and Si-O-Ti chemical bonds are formed during the thermal treatment process. The hiding power of Ti/SE-CPM composite is up to 85% of TiO2 white pigments, and the oil absorption value was equal to TiO2 white pigments. All these data demonstrated that the obtained Ti/SE-CPM samples have similar excellent properties compared with anatase TiO2 white pigments. Therefore, this study provides a feasible way of reducing the usage of TiO2 while maintaining similar pigment properties, which, of course, will reduce the cost, protect our environment and has a potential application in large-scale production of white pigments. [ABSTRACT FROM AUTHOR]

CeO 2 -SnO 2 nanocomposites were synthesized by simple chemical precipitation method. The composites were characterized by XRD, UV–vis, SEM, FE-SEM, HR-TEM, FT-IR and FT-Raman. X-ray diffraction result confirms the structure with good crystalline and size of the nanocomposites. HR-TEM results revealed formation of nanocomposite in spherical shape with less than 10 nm size and highly homogeneous. X-ray photoelectron spectroscopy confirmed the chemical composition and different ionization states of Ce3+/Ce4+, Sn4+ and O1s. Functional groups of nanocomposites were identified using FT-IR spectroscopy. FT-RAMAN spectra were used to identify the Raman shift, which supported the formation of nanocomposite. Thermal stability and phase changes of CeO 2 -SnO 2 nanocomposite were characterized by TG and DTA. Paramagnetic property of the nanocomposite at room temperature was studied by EPR technique. The results of cyclic voltammetry and amperometry studies demonstrated the electrocatalytic activity of CeO 2 -SnO 2 nanocomposites towards l -cysteine oxidation. The electrochemical studies showed that CeO 2 -SnO 2 composite detects L-cysteine linearly over a concentration range from 0.016 × 10−3 M to 2 × 10−3 M. The electrochemical sensor showed high sensitivity of 186.34 μA mM−1 cm−2 with lower detection limit of 0.016 × 10−3 M. Moreover, the sensor results showed good selectivity, excellent stability and reproducibility of the CeO 2 -SnO 2 nanocomposites as a promising candidate for L-cysteine sensing. Image 1 • CeO 2 -SnO 2 nanocomposites were synthesized by a simple chemical precipitation method. • The nanocomposite size was 10 nm with highly homogeneous. • The CeO 2 -SnO 2 was used as modify electrode for determination of the L-cysteine biomolecules. • Sensor results showed good selectivity, excellent stability and reproducibility. [ABSTRACT FROM AUTHOR]

In this study, benzimidazole and Zn2+ are deposited on the surface of AP particles through chemical precipitation to improve its thermal properties, energy properties and hygroscopicity. The results show that compared with pure AP, the HTD peak temperature and apparent activation energy of the AP@ZIF-7 (25 wt%) sample are reduced by 98.49 °C and 117.62 kJ·mol−1, respectively. The heat release during thermal decomposition increases by 1133.62 J·g−1. In addition, the contact angle between AP@ZIF-7 (25 wt%) and water is 79.19°, which is 66.09° higher than that of AP. At the same time, after being placed at a relative humidity of 88% for 72 h, its moisture absorption rate drops to 0.05 wt%, a decrease of 0.266 wt%. Moreover, compared with the propellant prepared with AP as oxidant, the burning rate of the propellant containing AP@ZIF-7 (25 wt%) increases by 5.28 mm·s-1, and the flame temperature increases by 873.17 °C. ZIF-7 was deposited on the surface of AP particles by chemical precipitation method, which is expected to comprehensively improve the hygroscopic, energy and thermal properties of AP. [Display omitted] • The ZIF-7 layer can cover the surface of AP particles uniformly and compactly. • The AP@ZIF-7 composites were successfully prepared. • The ZIF-7 layer can improve the thermal decomposition of AP. • The layer of ZIF-7 can improve the anti-hygroscopic performance of AP. • AP@ZIF-7 can increase the burning rate and burning temperature of the propellant. [ABSTRACT FROM AUTHOR]

Abstract Copper oxide (CuO) nanomaterials (NMs) of different size and morphology were synthesized by Chemical precipitation, Microwave irradiation and Hydrothermal method and characterized by TEM, BET, FTIR, XRD and EDX analysis. As synthesized CuO NMs were utilized for elimination of harmful dyes viz. Direct Red 81 (DR-81) and Coomassie Brilliant blue R-250 (BBR-250) and pathogenic bacteria (Staphylococcus aureus). Owing to their morphology, smaller size and relatively high surface area (40.320 m2 g−1), CuO NMs prepared by chemical precipitation method were observed to show better adsorption capacity for both the dyes (68.70 (DR-81) and 73.04 (BBR-250) mg g−1). The influence of different experimental conditions was studied by the methodical assessments of various parameters such as pH, adsorbent dose, concentration and contact time. Moreover, different adsorption isotherms and pseudo-second order kinetic model were applied to understand the adsorption mechanism. Langmuir model was found to be best fit thus confirming the monolayer adsorption process. To ensure the practical utility of CuO NMs for organic waste removal, the adsorption studies were performed in the presence of different inorganic ions and real water samples. In addition, recovery of the dye and NMs were also carried out effectively by simple method, thus avoiding the secondary pollution. CuO NMs were observed to exhibit significant antibacterial activity against the human pathogenic bacteria. These studies demonstrated that synthesized CuO NMs showed good adsorption efficiency for the removal of harmful dyes and antimicrobial activity against the pathogenic bacteria, which vary as a function of size and surface area. Highlights • Facile and non-toxic methods to synthesize CuO NMs of various shape and size. • CuO NMs exhibited effective dye removal and significant antibacterial activity. • CuO NMs were also efficient in eliminating dyes from field samples. • NMs fabricated via chemical precipitation method demonstrated better results. • NMs were successfully recovered with excellent chemical stability and further reused. [ABSTRACT FROM AUTHOR]

With the use of Paulownia wood as a substrate and a vacuum impregnation method, CaCO3/wood composites were prepared. The XRD results showed that a variety of types of calcium carbonates coexisted in the composite and the elevated temperature was favorable for the aragonite type. The SEM results showed the modified wood retained the original wood structure and that CaCO3 was uniformly distributed in the wood cell cavity and clung to the wood cells. The mechanical testing results showed that the mechanical properties of all the composites were obviously improved; the maximum value of strength of compression (SC) and modulus of elasticity (MOE) of the CaCO3/wood composites were 32.23 MPa and 0.92 GPa, respectively, values 44.2% and 53.3% higher than those of the original wood. The maximum value of proportional limit (PL) of the composites was 29.4 MPa (38.5% increase from original wood). A cone calorimeter was used to investigate the flame retardation properties of CaCO3 on the composites. The value of the heat release rate and total heat release of composites were lower than those of the original wood; the CaCO3 wood composites showed good flame retarding effects. [ABSTRACT FROM AUTHOR]

new material of Cu(OH)2 nanostructures was prepared using cupric nitrate and sodium hydroxide as raw materials by the chemical precipitation method. The Cu(OH)2 nanostructures were characterized by scanning electron microscope, transmission electron microscopy, infrared spectrometer, and X-ray diffractometer. The results showed that the Cu(OH)2 nanostructures exhibited excellent uniform and dispersion at 40°C. A series of factors was investigated to effect the photocatalytic efficiency of methyl orange (MO), such as the concentration of Cu(OH)2 nanostructures, the reaction time of the Cu(OH)2 nanostructures, the initial concentration of MO, and so on. As a result, the Cu(OH)2 nanostructures exhibited excellent photocatalytic efficiency with the concentration of 20 mg L-1 Cu(OH)2 nanostructures, the initial concentration of MO was 15 mg L-1 and the stirring time was 70 min. [ABSTRACT FROM AUTHOR]

UV and solar-based photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) as an organic contaminant in ceramics industry wastewater by ZnS and Fe-doped ZnS NPs was the focus of this research. Nanoparticles were prepared using a chemical precipitation process. The cubic, closed-packed structure of undoped ZnS and Fe-doped ZnS NPs was formed in spherical clusters, according to XRD and SEM investigations. According to optical studies, the optical band gaps of pure ZnS and Fe-doped ZnS nanoparticles are 3.35 and 2.51 eV, respectively, and Fe doping increased the number of carriers with high mobility, improved carrier separation and injection efficiency, and increased photocatalytic activity under UV or visible light. Doping of Fe increased the separation of photogenerated electrons and holes and facilitated charge transfer, according to electrochemical impedance spectroscopy investigations. Photocatalytic degradation studies revealed that in the present pure ZnS and Fe-doped ZnS nanoparticles, 100% treatment of 120 mL of 15 mg/L phenolic compound was obtained after 55- and 45-min UV-irradiation, respectively, and complete treatment was attained after 45 and 35-min solar light irradiation, respectively. Because of the synergistic effects of effective surface area, more effective photo-generated electron and hole separation efficiency, and enhanced electron transfer, Fe-doped ZnS demonstrated high photocatalytic degradation performance. The study of Fe-doped ZnS's practical photocatalytic treatment capability for removing 120 mL of 10 mg/L 2,4-DCP solution made from genuine ceramic industrial wastewater revealed Fe-doped ZnS's excellent photocatalytic destruction of 2,4-DCP from real industrial wastewater. [Display omitted] • Use of Fe-doped ZnS NPs for photocatalytic degradation of organic pollutants. • UV and solar-based photocatalytic degradation methods for treatment of wastewater. • The degradation efficiency increased with Fe-doping in ZnS NPs. • Fe-doped ZnS NPs can be a promising material for industrial wastewater treatment. [ABSTRACT FROM AUTHOR]

• Inhibition of Ca2+ in municipal solid waste incineration fly ash is investigated. • Chemical precipitation and electrochemical methods are innovatively coupled. • Space-time migration laws of Ca2+ in an electrokinetic cycle are studied. • Carbonate inhibition mechanism are revealed. • Effect of voltage gradient on Ca2+ precipitation is greater than that of carbonate. Based on the traditional electrokinetic repair method, the chemical precipitation method and electrochemical method are innovatively coupled in this study. Taking the municipal solid waste incineration (MSWI) fly ash produced by a thermal power plant as the research object, an electrokinetic experiment is carried out. By changing the content of sodium carbonate and the voltage gradient, the change laws of electrolyte interface, electrolyte current and Ca2+ concentration are analyzed. Besides, the space–time migration law of soluble Ca2+ in a certain electrokinetic cycle and the carbonate inhibition mechanism are revealed. By means of SEM-EDS and XRD, the elemental composition and micro morphology of fly ash before and after treatment are studied, and the components of precipitation products are determined. The results show that, when the contents of sodium carbonate reach 6.6 % and 9.9 %, the white Ca(OH) 2 floc in the electrolyte can be obviously observed to transform into CaCO 3 precipitation, so as to achieve an ideal inhibition effect. Simultaneously, the influence of voltage gradient on Ca2+ precipitation is greater than that of sodium carbonate. The inhibition mechanism of soluble Ca2+ is mainly through changing the chemical equilibrium of Ca(OH) 2 -CaCO 3 system, and then forming stable CaCO 3 precipitation. [ABSTRACT FROM AUTHOR]

Heterostructured AgBr/Bi 2 Sn 2 O 7 photocatalysts were synthesized successfully via the ultrasonic-assisted chemical precipitation method. XRD, FT-IR, FE-SEM, TEM, XPS, UV–vis-DRS and PL spectroscopy were used to characterize the phase structure, morphology, chemical composition, oxidation state, and optical properties of AgBr/Bi 2 Sn 2 O 7 heterojunction. The photocatalytic activity of as-prepared catalysts was evaluated by the degradation of RhB under visible light irradiation. The obtained AgBr/Bi 2 Sn 2 O 7 composite with the 1:1 molar ratio exhibited significantly enhanced photocatalytic performance. Further first-principles calculations indicated that the hybridization interaction between Ag and O atoms at AgBr/Bi 2 Sn 2 O 7 interface is expected to be beneficial for enhancing the charge transfer and improving the photocatalytic activity of heterostructured composites. [ABSTRACT FROM AUTHOR]

Undoped and Mn 2+ doped CdOZn 3 (PO 4 ) 2 nanocomposites are fruitfully synthesized by chemical precipitation process at room temperature. The morphology, structure and spectroscopic properties of the prepared samples are characterized by X-ray diffraction (XRD), optical absorption, Scanning electron microscope (SEM) with EDS, Fourier transform infrared (FT-IR) spectroscopy, Photolumiscence (PL) and Electron Paramagnetic Resonance (EPR). XRD data confirms the cubic phase of CdO and monoclinic phase of Zn 3 (PO 4 ) 2 . Strain and dislocation density are also calculated from XRD studies. Optical absorption spectrum of Mn 2+ doped CdOZn 3 (PO 4 ) 2 nanocomposite shows different spin-forbidden DMSO- d 6 bands which are the characteristics of octahedral site symmetry related to Mn 2+ . The crystal field parameter Dq and inter electronic repulsion parameters (B and C) are deliberate using optical absorption data. Surface morphology of sample is firm by Using Scanning electron microscopy (SEM) and the distribution of Zn, Cd, phosphate and oxygen species in the prepared sample is identified by EDS. PL studies recognize the white light emission. The ‘g’ value of the nanocomposite material synthesized is lesser than (negative shift) the free electron value (2.0023), which gives ionic nature to the bonding and confirms the presence of Mn 2+ in distorted octahedral site symmetry. [ABSTRACT FROM AUTHOR]

In recent years, transition metal sulfides have been regarded as a promising energy storage material for supercapacitors, due to their high theoretical specific capacity and conductivity compared with other similar metal oxides and hydroxides. However, the sluggish diffusion dynamics and low capacitance impede its practical implement application. Herein, an advanced 3D nanocomposite of NiCo 2 S 4 /CuCo 2 S 4 heterostructure was designed via a time-saving, safe and efficient approach. The mass transfer kinetics of NiCo 2 S 4 /CuCo 2 S 4 nanocomposite has been significantly promoted owing to this novel heterostructure. Therefore, the NiCo 2 S 4 /CuCo 2 S 4 electrode materials reveal a superior specific capacitance (180.8 mAh g−1 at 2 A g−1) and excellent rate properties (84.7% capacitance retention from 2 to 20 A g−1). The asymmetric supercapacitor device assembled with NiCo 2 S 4 /CuCo 2 S 4 and activated carbon has an energy density of 37.0 Wh kg−1 at 400 W kg−1 and outstanding cyclic stability (93.3% remained after 10,000 cycles at 10 A g−1). Density functional theory (DFT) calculation further proves the electronic structure and the charge transfer can be tuned by the heterostructure of NiCo 2 S 4 and CuCo 2 S 4. This work offers a new perspective to design a high-performance electrode material in the field of supercapacitors. [Display omitted] • A 3D NiCo 2 S 4 /CuCo 2 S 4 nanoparticles composite was synthesized by a time-saving chemical deposition method. • NiCo 2 S 4 /CuCo 2 S 4 composite has a larger specific surface area than NiCo 2 S 4 or CuCo 2 S 4. • The heterostructure of NiCo 2 S 4 /CuCo 2 S 4 improves charge transport capacity. • The materials reveal a capacitance (180.8 mAh g−1 at 2 A g−1), rate properties (84.7% retention from 2 to 20 A g−1). [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnO and 3 wt% Tb-ZnO NPs were effectively fabricated by simple chemical co– precipitation method. • Fine-tuning the optical properties of ZnO by Tb ion doping. • The specific surface area was analysed by the single point Brunauer Emmet Teller (BET) for surface area analyzer. • Enhanced the electrochemical sensing behaviour of ZnO/MCPE towards moxifloxacin drug by Tb doping ion doping. • To evaluate the antibacterial activities of pure ZnO and Tb-ZnO NPs. Chemical co-precipitation method was adopted for the synthesize of ZnO and 3 wt% Tb doped ZnO (Tb-ZnO) nanoparticles (NPs) using ascorbic acid as a capping agent and its Optical, photoluminescence, electrochemical-sensing and antibacterial properties were investigated. Formation of hexagonal wurtzite structure was confirmed by XRD studies. FTIR shows strong absorption and stretching vibration between the molecules. The samples morphology was identified by SEM and TEM micrographs. Elemental composition was done by EDXA spectroscopy. S pecific surface area and porosity of Tb-ZnO NPs have been examined by BET method. The influence of Tb content on bandgap was analyzed by UV–Vis spectra; the band gap was originating to be 3.2 and 3.56 eV for undoped ZnO and Tb-ZnO NPs, respectively. PL study confirmed the existence of various types of defects as well as band edges. Electrochemical routines in the direction of moxifloxacin drug were ominously examined via dopant and supplementary results stood established through Tb-ZnO as electrode was made of modified carbon paste (Tb-ZnO/MCPE) by cyclic Voltammetric technique. The antibacterial activities of ZnO and Tb-ZnO NPs were studied by agar well diffusion technique as opposed to pathogenic bacterial strains. [ABSTRACT FROM AUTHOR]

Nano-hydroxyapatite samples with different morphologies were successfully prepared by chemical precipitation method using polyethylene glycol (PEG) as a template. The phase composition, micro-morphology and surface functional groups of the nano-hydroxyapatite samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), respectively. The results reveal that the mirco-morphology of hydroxyapatite can be effectively controlled by adjusting pH values in the preparation. Moreover, the growth mechanism of HAp with different morphologies was also discussed. [ABSTRACT FROM AUTHOR]

Ni 2 P/ZnO core/shell composites were fabricated basing on combining hydrothermal route with a facile chemical precipitation method. The characterization results show that the composites are comprised of the hexagonal Ni 2 P microspheres and hexagonal ZnO nanoparticles. In which, ZnO nanoparticles coat on the surfaces of Ni 2 P microspheres and some of them even assemble to worm-like structure. During the coating process, Zn 2+ was absorbed on the surface of Ni 2 P microspheres by electrostatic interaction and then formed ZnO shell. But excessive Zn 2+ can affect the crystalline and formation of core-shell structure of Ni 2 P/ZnO composites, so it is necessary to control the amount of Zn 2+ . Choosing Methylene Blue (MB) as a typical organic dye, the as-prepared Ni 2 P/ZnO core/shell composites show the enhanced photocatalytic degradation activity, which may be due to its better adsorption ability and the effective separation of photogenerated electron–hole pairs. [ABSTRACT FROM AUTHOR]

Novel hexagonal ring structured PbO/CdO/ZnO and spherical shaped PbS/CdS/ZnS nanocomposites were successfully synthesized by chemical method in air. Structural, morphological, chemical composition, optical, electrochemical and thermal properties were investigated using different analytical techniques. In comparison with the PbO/CdO/ZnO, PbS/CdS/ZnS nanocomposites showed well-defined cyclic voltammetric response. Optical absorption as well as emission peak position of the annealed nanocomposites was significantly red shifted compared with the as-prepared samples. To prevent the toxic effect of the Pb–Cd, the environment friendly Zn was coated on the surface of binary composites. The combined electrochemical and optical experiments indicated that PbO/CdO/ZnO and PbS/CdS/ZnS nanocomposites can be considered as efficient candidates for optical and electrochemical applications. Phase transition, decomposition and stability of the nanocomposites were identified by thermal study. [ABSTRACT FROM AUTHOR]

A novel paraffin@SiO 2 shape-stabilized composite phase change material (ss-CPCM) was fabricated by chemical precipitation process using sodium silicate precursor. Various techniques were used to characterize the as-prepared paraffin@SiO 2 ss-CPCM so as to investigate its structure and thermal properties, including Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and thermal conductivity measurement. The SEM results show that the microstructures of the prepared ss-CPCM are some uniform submicron particles. The FTIR and XRD results showed that there was no chemical interaction between paraffin and SiO 2 matrix. The DSC analysis results indicated that the paraffin@SiO 2 ss-CPCM achieved high encapsulation efficiency and desirable latent heat storage capability. The thermal conductivity of the composite was also significantly improved compared with pure paraffin. According to the TGA results and the thermal cycling tests, the prepared ss-CPCMs had a good thermal stability. The prepared paraffin@SiO 2 ss-CPCM with enhanced heat transfer and phase change properties holds great promise for building energy conservation owing to the low cost of raw materials and the simple synthetic technique. [ABSTRACT FROM AUTHOR]

Chemical precipitation method was used for the synthesis of Mn 2+ doped ZnO-CdS composite nanopowder. The effect of Mn 2+ doping was investigated on their structural, optical and magnetic properties. XRD pattern reveals the hexagonal phase of ZnO as well as CdS and the average crystallite size is found to be 18 nm. The morphological studies show non-uniformly distributed spherical like structures with little agglomeration. Crystal field and interelectronic repulsion parameters are evaluated from optical absorption study. EPR spectrum exhibits a well resolved sextet at g = 1.9924. By correlating optical and EPR studies, Mn 2+ ions occupy octahedral sites in the host lattice which is also confirmed by PL analysis. From 1931 CIE chromaticity diagram, the prepared sample exhibits orange-red emission. IR spectrum confirms the existence of Zn-O and Cd-S vibrational modes. Room temperature ferromagnetism is observed in the prepared sample. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) nanoparticles were synthesised by a simple chemical precipitation method in various media, such as acidic, basic and neutral. Hydrochloric acid and sodium hydroxide were used to maintain the different pH levels and tungstic acid was used as the precursor for the synthesis of tungsten oxide. The resultant nanoparticles were studied by different characterisation techniques. Powder X-ray diffraction shows that the average crystallite size of the WO3 is about 13 nm and exhibits stable orthorhombic phase for different pH values. Particle size and the surface morphology of the synthesised material were studied by TEM analysis. Chemical composition and surface area of the nanoparticles were studied by FTIR and BET measurements. Optical properties of the synthesised nanoparticles were studied by UV-Vis absorption and photoluminescence spectroscopy. Band gap (∼2.7 eV) of the synthesised WO3 was investigated from the optical absorption spectra. At room temperature, a strong PL blue emission peak at ∼440 nm was observed for the synthesised tungsten oxide nanomaterials. Thermal stability of the synthesised material was studied by TG/DTA analysis. Cyclic voltammetry illustrated the electrochemical response of the WO3 nanoparticles using KCl as electrolyte. The peak separation of 182 mV, 153 mV and 77 mV for the acidic, basic and neutral media were observed. Thus it was confirmed that, tungsten oxide has a low peak separation, a fast reaction rate and electron transfer rate in neutral medium. [ABSTRACT FROM AUTHOR]

In the present work, solution based simple chemical precipitation method has been used to prepare undoped and Ni-doped ZnS nanoparticles. Zinc acetate, sodium sulfide, and nickel nitrate have been used as precursors for the preparation of Ni-doped ZnS nanoparticles. The X-ray diffraction results revealed that the undoped and Ni-doped ZnS nanoparticles exhibit hexagonal Structure. The average grain size of the prepared nanoparticles was found to lie in the range of 2.6–4.2 nm. The SEM images show that the particles have smooth surface and the formation of agglomerated nanoparticles. The compositional analysis results confirm the presence of Ni, Zn and S in the prepared samples. The optical properties of undoped and Ni-doped ZnS quantum dots have been studied using absorption spectra. HRTEM results show that undoped and Ni-doped ZnS nanoparticles exhibit a uniform size distribution with average grain size lying in the range of 2.3–3.6 nm. The synthesized nanoparticles exhibited an emission peak centered at around 612 nm in the PL spectrum. [ABSTRACT FROM AUTHOR]

Highlights: [•] α-Fe2O3 nanoparticles was prepared by chemical precipitation technique. [•] Crystallite size and lattice parameters were determined by XRD analysis. [•] Direct and indirect band gap energies were calculated from UV-DRS. [•] FTIR study determined functional and compositional changes of nanoparticles. [•] SEM with EDX revealed that the morphological and elemental identification. [Copyright &y& Elsevier]

Abstract: Hematite (α-Fe2O3) nanoparticles were synthesized from the ferrihydrite precursor via a simple chemical precipitation method with trace amounts of Fe(II) as the catalyst under nitrogen atmosphere. The characteristic of the synthesized hematite particles were evaluated by XRD, FT-IR, and FE-SEM. The magnetic and electrical properties were studied by a vibrating sample magnetometer (VSM) and an electrometer, respectively. The synthesized products were of a single phase of the hexagonal structure hematite without any other impurities. The physical morphology of the synthesized hematite appears to be composed of a large number of very small particles appearing as the “raspberry shape”. The particle size of the synthesized hematite can be successfully controlled at 50–150nm, appearing as three different morphologies: the spherical-like, the cubic-like, and the ellipsoidal shape, through adjusting the synthesis conditions. The smallest particle possesses the highest electrical conductivity of 5.2×10−3 s/cm. On the other hand, the largest particle exhibits weak ferromagnetism and the highest saturation magnetization (M s) of 1.94emu/g, is higher than that of the smaller particle, which possesses the super-paramagnetic behavior. Furthermore, the different particle shapes are shown here to critically affect the electrical and magnetic properties of the nanoparticles. [Copyright &y& Elsevier]

NaCrF crystals with unique morphology were prepared by a chemical precipitation method. Through XRD and FESEM analysis, the shape characteristics of the NaCrF crystals were studied. The results indicated that the terminal pH and concentration of Cr and NaF encouraged the growth of spherical, truncated cuboid, concave cubic and cubic shape NaCrF crystals. Molecular simulations revealed that shape formation was due to crystal bonding energy. [ABSTRACT FROM AUTHOR]

Abstract: ZnS:Fe/MX (M=Cd, Zn; X=S, Se) nanocrystals were synthesized by chemical precipitation method. Compared to ZnS:Fe nanocrystals, the diffraction peaks intensity of ZnS:Fe/ZnS nanocrystals reduced and the diffraction peaks of ZnS:Fe/ZnSe nanocrystals moved to lower angles. TEM photos show that ZnS:Fe and ZnS:Fe/ZnSe nanocrystals are spheroidal and the average particles size is about 2–4nm. The selected-area electron diffraction pattern of ZnS:Fe/ZnSe nanocrystals shows the diffraction rings, indicating the ZnS:Fe/ZnSe nanocrystals have a polycrystalline structure. XPS shows that the divalent and trivalent of Fe ion are coexisted in ZnS:Fe nanocrystals. The emission peaks of ZnS:Fe nanocrystals were from S and Zn ions vacancy defects and surface defects for the range of 200–900nm. The use of ZnS (CdS, ZnSe) as surface modifying reagent inhibited the luminescent intensity of ZnS:Fe nanocrystallines at 420nm. The PL spectra of ZnS:Fe/CdS nanocrystals show a new peak at 554nm. [Copyright &y& Elsevier]

Abstract: ZnO quantum-dot chains codoped with Eu3+ and Er3+ were synthesized by the chemical precipitation method and the codoping effects on the structures, morphologies and optical properties of the powders were briefly investigated. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results indicated the Eu3+ and Er3+ were incorporated into the crystal lattice of ZnO host. Transmission electron microscope (TEM) measurements showed the sizes of the ZnO quantum dots decreased with the increase of Eu3+ and Er3+ doping concentration, and the quantum-dot chains were formed by codoping with Eu3+ and Er3+. The green emissions in the photoluminescence spectra were attributed to 4f–4f of Er3+ inner shell 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions, and the characteristic red emissions of Eu3+ ions were attributed to the 5D0 → 7F1 and 5D0 → 7F2 transitions, respectively. Moreover, the red emission of the Eu3+ ions gradually decreased with the Er3+ ions doping concentration increased, which may be due to the different energy storage centers in the powders. [Copyright &y& Elsevier]

Photocatalytic degradation of methylene blue was investigated using nanocrystalline ZnO prepared by chemical precipitation and thermal decomposition routes. In both preparation routes zinc acetate dihydrate was used as the precursor. In the case of precipitation route, sodium hydroxide was used as the precipitating agent at room temperature, but in thermal decomposition method the precursor was just calcined at 450°C for 30 min. The structural and morphological properties were studied by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The sample prepared by precipitation route exhibits higher photocatalytic activity than that by thermal decomposition method and the reasons for the enhanced photocatalytic activity have been discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract: ZnO nanoparticles (NPs) have been successfully synthesized by the chemical precipitation method in different atmospheres at 500°C. The annealing atmospheres were argon, forming gas (50% Ar/50% O2) and air, respectively. The effects of annealing atmosphere on the structure and optical properties of ZnO NPs were investigated in detail by X-ray diffraction, transmission electron microscope, photoluminescence and Raman scattering measurements. The results showed that the as-prepared ZnO NPs had a hexagonal wurtzite structure, and all the samples kept the overall crystal structure of bulk ZnO. From the Raman and photoluminescence spectra, it can be seen that the content of oxygen in different annealing atmospheres strongly influenced the crystallization and light emission of the ZnO NPs. The results revealed that the content of oxygen in air was the optimal condition for growing the ZnO NPs with the best crystalline quality and optical properties. Defect emission was significantly enhanced by annealing in Ar atmosphere, which indicated that the green defect emission was most likely due to oxygen vacancy. Moreover, the effect mechanism of annealing atmospheres on the structure and optical properties of ZnO NPs were also investigated. [Copyright &y& Elsevier]

Abstract: ZnO nanoparticles (NPs) have been successfully prepared by the chemical precipitation method at a low temperature of 200°C. X-ray diffraction (XRD), transmission electron microscope (TEM), photoluminescence (PL) and Raman were used to investigate the effect of annealing temperature on the structure and optical properties of ZnO NPs. The XRD analyses revealed that the average size of the as-prepared samples was about 8nm under 200°C, which had a good agreement with TEM images. Raman spectra showed that the E2 (high) mode became stronger and sharper with the increase of annealing temperature, but the intensity of phonon peak located at 580cm−1 was relatively suppressed. The position of ultraviolet (UV) emission peak in the room-temperature PL spectra showed a red-shift when the annealing temperature was increased. In addition, after annealing under 500°C, the intensity of the UV peak became strongest and the intensity of the green emission almost disappeared, which indicated that ZnO NPs have much better crystallization after annealing. [Copyright &y& Elsevier]

Abstract: Nano-sized amorphous CaSiO3 (A-CS) and β-wollastonite (β-CS) powder were produced by chemical precipitation method and subsequent heat treatment, using Ca(NO3)2·4H2O and Na2SiO3·9H2O as the starting materials, polyethylene glycol as the dispersant. Bulk materials were produced using the two powders as precursors. Rough, porous, and elongated particles occurred in A-CS material and the grains of β-CS were smooth, dense, and spheric. The particle sizes of A-CS and β-CS were about 40 nm and 90 nm in diameter respectively. The bioactivities of A-CS and β-CS materials were investigated by soaking the two materials in SBF solution at 36.5 °C for 6 h to 15 days. Experiment results revealed that CaCO3 crystallized accompanied with HAP on the A-CS surfaces. HAP crystallized constantly on the surfaces of β-CS. The HAP layer formed on β-CS was composed of uniformly sized particles. A layer of irregular particle size was formed on the A-CS owing to the co-existence of CaCO3. The A-CS showed a faster formation of HAP due to the high release rate of Ca ion. [Copyright &y& Elsevier]

Development of the composites based on substances with a high bioactivity potential is of current interest to medical materials science because composites' properties can be modified by varying the components ratios. Weakly crystallized calcium phosphates and calcium silicate hydrates, possessing higher chemical reactivity than their crystalline forms, are promising salts to be studied as biomaterials' constituents. In this study, precipitation from aqueous solutions was employed to obtain apatite and calcium silicate hydrate composites. Synthesized solids were examined without high-temperature thermal pretreatment using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), laser diffraction, physical adsorption (BET method) and thermogravimetric analysis coupled with the mass spectrometry (TGA/MS). Compositions containing poorly crystallized carbonate-substituted hydroxyapatite, calcium silicate hydrate and calcite as an admixture were obtained by varying concentrations of the reagents. Soaking of the composite ceramics formed from freshly precipitated synthetic solids in simulated body fluid (SBF) at 37 °C for 14 days lead to formation of the surface layer of amorphous calcium phosphate. As the calcium silicate content in the composites increases, the coating's density and thickness also increase, because silicate ions act as active sites in the process of new phase nucleation. Furthermore, prismatic calcite crystals were identified to form on the lower side of ceramics. This may be caused by an increasing of local supersaturation with respect to calcium carbonate in small-volume confinement conditions during the experiment. • Hydroxyapatite and calcium silicate composites could be obtained by coprecipitation. • Calcium salts are homogeneously distributed in mixtures at a quasi-molecular level. • An amorphous calcium phosphate layer forms on composites ceramics in model solution. • Calcium phosphate layer the thicker the more calcium silicate content in composite. • Calcite forms on tablets side that contact with a limited volume of model solution. [ABSTRACT FROM AUTHOR]

• Room temperature ferromagnetism is observed for 2% Co doped nanoparticles synthesized by a chemical route. • Bound magnetic polarons due to the oxygen vacancies and surface defects are the major reasons for the observed room temperature ferromagnetism. • EXAFS and XPS analysis showed the existence of Co2+ in tetrahedral sites of wurtzite lattice. • Undoped ZnO shows photo-catalytic degradation for Rhodamine dye under UV and solar irradiation. We have observed ferromagnetism at room temperature in 2% cobalt doped ZnO nanoparticles prepared by a simple chemical precipitation method. This can be described as a consequence of bound magnetic polaron (BMP) resulting from the occurrence of oxygen vacancies and surface defects in the sample. Photoluminescence and Raman measurements indicate the existence of such defects in the sample. Electron Spin Resonance (ESR) studies are done to probe into the magnetic nature of the doped samples further. Redshift in the band gap and formation of characteristic absorption bands after Co doping shows that Co ions are incorporated in the host ZnO lattice. The infrared sensitive vibrational modes are identified with Fourier Transform Infrared Spectroscopy (FTIR) measurements. The spin-orbital splitting in X- ray Photoelectron Spectroscopic (XPS) measurements show the matching oxidation (divalent) state among the dopant and the host. Local structural studies after Co doping by the Extended X-ray Absorption Fine Structure (EXAFS), shows the Co2+ integration in the ZnO lattice without any impurity states. Photocatalytic measurements show that ZnO is a very promising degrading agent for Rhodamine B dye solution under UV as well as solar irradiation. [ABSTRACT FROM AUTHOR]