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In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping levels (2%, 4%, 6%, and 8%) without disrupting the overall lattice configuration. The average particle size for undoped ZnS was found to be 5.27 nm, while the Ni-doped samples exhibited sizes ranging from 5.45 nm to 5.83 nm, with the largest size observed at 6% Ni doping before a reduction at higher concentrations. Fourier-transform infrared (FTIR) spectroscopy identified characteristic Zn–S vibrational bands, with shifts indicating successful Ni incorporation into the ZnS lattice. UV–visible spectroscopy revealed a decrease in the optical band gap from 3.72 eV for undoped ZnS to 3.54 eV for 6% Ni-doped ZnS, demonstrating tunable optical properties due to Ni doping, which could enhance photocatalytic performance under visible light. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the uniform distribution of Ni within the ZnS matrix, while X-ray photoelectron spectroscopy (XPS) provided further confirmation of the chemical states of the elements. Ni doping of ZnS nanoparticles alters the surface area and pore structure, optimizing the material's textural properties for enhanced performance. These findings suggest that Ni-doped ZnS nanoparticles offer promising potential for applications in photocatalysis, optoelectronics, and other fields requiring specific band gap tuning and particle size control. [ABSTRACT FROM AUTHOR]

Two forms of flower-like ZnO nanostructures were synthesized using hydrothermal methods at various growth times/temperatures and zinc precursors. The morphology, structure, chemical composition, and optical properties of these ZnO nanoflowers were studied using a scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectrons spectroscopy (XPS), Raman spectroscopy, and UV–Vis spectroscopy. The SEM images revealed two forms of flower-like nanostructures, namely lotus- and tulip-like flower ZnO nanostructures. The XPS analysis revealed the oxidation state of the Zn and O elements, as well as the presence of OH groups on the surface of the lotus-like flower ZnO nanostructure. The XRD results revealed less crystallinity of the lotus-like ZnO nanoflowers (NFs) compared with the tulip-like ZnO NFs. The XRD results revealed the presence of Zn (OH)2 in the ZnO NFs. The Raman results confirmed less crystallinity of the lotus-like ZnO NFs. The estimated optical bandgap was 2.92 and 3.0 eV for the tulip- and lotus-like ZnO NFs, respectively. The tulip-like ZnO NFs showed superior photocatalytic degradation of methylene blue dye, verified via UV–Vis radiation, compared with the lotus-like ZnO NFs, which show the impact of the structure defects and OH- impurities on the photocatalytic performance of ZnO nanoflowers. [ABSTRACT FROM AUTHOR]

This study tackles the critical demand for sustainable synthesis methods of reduced graphene oxide (rGO), highlighting the environmental drawbacks of conventional chemical processes. We introduce a novel, green synthesis technique involving the irradiation of a 500 eV argon ion beam, which not only facilitates the creation of micro-patterned rGO on a graphene oxide (GO) film but also enables simultaneous material characterization and patterning. By adjusting the irradiation exposure time between 0 and 80 s, we achieve meticulous control over the attributes and the reduction process of the material. The use of X-ray photoelectron spectroscopy (XPS) allows for real-time monitoring of the reduction from GO to rGO, evidenced by a notable reduction in the intensities of C-O, C=O, and O-C=O bonds, and an increase in C-C bond intensities, indicating a significant reduction level. Our research demonstrates the efficient production of eco-friendly rGO using precise, controlled argon ion beam irradiation, proving its advantages over traditional methods. These results contribute to the development of sustainable material science technologies, with potential applications in electronics, energy storage, and more. [ABSTRACT FROM AUTHOR]

This study aims to prepare new nanocomposites consisting of Cr2O3/CaCO3 as a catalyst for improved hydrogen production from NaBH4 methanolysis. The new nanocomposite possesses nanoparticles with the compositional formula Cr2−xCaxO3 (x = 0, 0.3, and 0.6). These samples were prepared using the sol-gel method, which comprises gelatin fuel. The structure of the new composites was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, environmental scanning electron microscopy (ESEM), and X-ray spectroscopy (XPS). The XRD data showed the rhombohedral crystallinity of the studied samples, and the average crystal size was 25 nm. The FTIR measurements represented the absorption bands of Cr2O3 and CaO. The ESEM micrographs of the Cr2O3 showed the spherical shape of the Cr2O3 nanoparticles. The XPS measurements proved the desired oxidation states of the Cr2−xCaxO3 nanoparticles. The optical band gap of Cr2O3 is 3.0 eV, and calcium doping causes a reduction to 2.5 and 1.3 eV at 15.0 and 30.0% doping ratios. The methanolysis of NaBH4 involved accelerated H2 production when using Cr2−xCaxO3 as a catalyst. Furthermore, the Cr1.7Ca0.3O3 catalyst had the highest hydrogen generation rate, with a value of 12,750 mL/g/min. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of the full-scale replacement (up to 100%) of Ca2+ ions with Ag1+ ions in the structure of brushite (CaHPO4·2H2O). This substitution has potential benefits for producing monophasic and biphasic Ca1−xAgxHPO4·nH2O compounds. To prepare the starting solutions, (NH4)2HPO4, Ca(NO3)2·4H2O, and AgNO3 at different concentrations were used. The results showed that when the Ag/Ca molar ratio was below 0.25, partial substitution of Ca with Ag reduced the size of the unit cell of brushite. As the Ag/Ca molar ratio increased to 4, a compound with both monoclinic CaHPO4·2H2O and cubic nanostructured Ag3PO4 phases formed. There was a nearly linear relationship between the Ag ion ratio in the starting solutions and the wt% precipitation of the Ag3PO4 phase in the resulting compound. Moreover, when the Ag/Ca molar ratio exceeded 4, a single-phase Ag3PO4 compound formed. Hence, adjusting the Ag/Ca ratio in the starting solution allows the production of biomaterials with customized properties. In summary, this study introduces a novel synthesis method for the mono- and biphasic Ca1−xAgxHPO4·nH2O compounds brushite and silver phosphate. The preparation of these phases in a one-pot synthesis with controlled phase composition resulted in the enhancement of existing bone cement formulations by allowing better mixing of the starting ingredients. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) and Neodymium (III) oxide (Nd2O3) were combined to synthesized flexible innovative PVA/Nd2O3 polymer composite samples utilizing a solution casting approach for use in dielectric devices. The XRD, FTIR, and SEM methods are all investigated to characterize the composite films. In a frequency of 50 Hz to 5 MHz, the effects of additive Nd2O3 on the dielectric behavior of PVA were recorded. The PVA/Nd2O3 composite films were successfully fabricated, as shown by XRD and infrared spectroscopy. The scanning microscopy pictures showed that the Nd2O3 was loaded and distributed uniformly throughout the PVA. After the incorporation of Nd2O3, the composite PVA/Nd2O3 has a conductivity of 6.82 × 10−9 S·cm−1, while the PVA has a conductivity of 0.82 × 10−9 S·cm−1. Another improvement is the decrease in the relaxation time from 14.2 × 10−5 s for PVA to 6.35 × 10−5 s for PVA/Nd2O3, and an increase in the dielectric constant of 0.237 for PVA to 0.484 at a frequency of 100 Hz. The results showed that the composite samples have considerable changes as flexible films in different applications, including batteries and electronic circuits. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the effect of a complete exchange of Ca2+ with Zn2+ ions on the structure of brushite (CaHPO4·2H2O), which might be advantageous in the production process of CaxZn1−xHPO4·nH2O. To acquire the starting solutions needed for the current study, (NH4)2HPO4, Ca(NO3)2·4H2O, and Zn(NO3)2·6H2O were utilized in several molar concentrations. The findings indicate that Ca is partly substituted by Zn when the Zn/Ca molar ratio is below 0.25 and that Zn doping hinders the crystallization of brushite. A continued increase in the Zn/Ca molar ratio to 1 (at which point the supersaturation of the Zn solution rises) led to a biphasic compound of monoclinic brushite and parascholzite precipitate. Elevating the Zn/Ca molar ratio to 1.5 resulted in a precipitate of a parascholzite-like mineral. Finally, increasing the Zn/Ca molar ratio to 4 and above resulted in the formation of the hopeite mineral. Future biomaterial production with specific and bespoke characteristics can be achieved by adjusting the Zn/Ca ratio in the starting solution. It Rhas been established that the Zn/Ca ratio in the starting solution can be adjusted to obtain minerals with specific compositions. Thus, new synthesis methods for parascholzite and hopeite were introduced for the first time in this manuscript. [ABSTRACT FROM AUTHOR]

The influence of ionic substitution in the Ca1−xCoxHPO4·nH2O compound was studied systematically for the first time. Among the fascinating features of these biomaterials is that they can be easily tailored for specific applications, for example, as biocements and bioceramics. Different molar concentrations of Co(NO3)2·6H2O, Ca(NO3)2·4H2O, and NaH2PO4·2H2O compounds were employed in determining the starting solutions utilized in the present study. The experimental findings reveal that, when the Co/Ca molar ratio is below 0.67 (BCo4), Co doping (the partial substitution of Ca by Co) takes place in brushite as a monophase. However, in the Co/Ca 0.67–1.5 molar ratio range (BCo4–BCo6), biphasic Co3(PO4)2·8H2O/CaHPO4·2H2O crystals start to precipitate. Full Ca replacement by Co results in the precipitation of nanostructured monoclinic cobalt phosphate and orthorhombic ammonium cobalt phosphate hydrate. Subsequent X-ray photoelectron spectroscopy (XPS), powdered X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses, along with thermogravimetric analysis (TGA), confirmed that the starting solution ratio of Co/Ca had a significant influence on the material's microstructure, while tuning this ratio ultimately tailored the desired properties of the material for the intended applications. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of the full-scale replacement (up to 100%) of Ca 2+ ions with Ag 1+ ions in the structure of brushite (CaHPO 4 ·2H 2 O). This substitution has potential benefits for producing monophasic and biphasic Ca 1-x Ag x HPO 4 ·nH 2 O compounds. To prepare the starting solutions, (NH 4 ) 2 HPO 4 , Ca(NO 3 ) 2 ·4H 2 O, and AgNO 3 at different concentrations were used. The results showed that when the Ag/Ca molar ratio was below 0.25, partial substitution of Ca with Ag reduced the size of the unit cell of brushite. As the Ag/Ca molar ratio increased to 4, a compound with both monoclinic CaHPO 4 ·2H 2 O and cubic nanostructured Ag 3 PO 4 phases formed. There was a nearly linear relationship between the Ag ion ratio in the starting solutions and the wt% precipitation of the Ag 3 PO 4 phase in the resulting compound. Moreover, when the Ag/Ca molar ratio exceeded 4, a single-phase Ag 3 PO 4 compound formed. Hence, adjusting the Ag/Ca ratio in the starting solution allows the production of biomaterials with customized properties. In summary, this study introduces a novel synthesis method for the mono- and biphasic Ca 1-x Ag x HPO 4 ·nH 2 O compounds brushite and silver phosphate. The preparation of these phases in a one-pot synthesis with controlled phase composition resulted in the enhancement of existing bone cement formulations by allowing better mixing of the starting ingredients.

The current investigation deals with the treatment of water pollution that is caused by the leaching of nickel ions from the metallurgical industry and new-energy batteries. Therefore, an eco-friendly treatment of nickel through the use of a composite of cotton stalk biochar with nanozerovalent copper has been presented in this investigation signifying the impact of zerovalent copper in enhancing the adsorption capacity of biochar for nickel adsorption. Thermogravimetric analysis data showed the adsorbent to be significantly stable in the higher thermal range, whereas transmission electron microscopy analysis confirmed the particles to be 27 nm and also showed the cubic geometry of the particles. A much closer scanning electron microscopy analysis shows the morphology of particles to be cubic in shape. Batch adsorption indicated a positive influence of pH increase on adsorption due to the electrostatic attraction between positive nickel ions and post point of zero charge (pH PZC ) negative surface of copper biochar composite (pH > 5.5). A high adsorption rate was observed in the first 60 min, whereas adsorption increased with the increase in temperature from 303 to 318 K. Kinetic modeling confirmed the pseudo-first-order to fit best to the data. The apparent activation energy (11.96 kJ mol -1 ) is indicative of the chemical nature of the process. The adsorption data fitted well to the Langmuir adsorption model. The negative values of apparent Δ G ° and the positive values of apparent Δ H ° indicate the spontaneity and endothermicity of the process, respectively, whereas the positive values of apparent Δ S ° point toward increased randomness during the process. Postadsorption XPS suggests the adsorption of nickel on the surface of biochar composites in the form of Ni(OH) 2 and NiO(OH)., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)