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This work presented the removal of nitrate ions in aqueous solution based on silica nanoparticles (SiNPs), which were extracted from rice husk ash. The optimal conditions for nitrate ion adsorption were studied including pH, contact time, adsorbate concentration, and amount of absorbance. The surface morphological analysis showed that the SiNPs extracted (purity of 98%) were around 50 nm with a surface area of 30 m2·g−1 and adsorption average pore width of 2.72 nm, offers possibility for high capability of nitrate ion removal. The experimental results showed that the nitrate ion capability of adsorption was obtained around 14.22 mg·g−1 with a concentration range from 0 to 25 mg·L−1 based on optimizing conditions including pH 6, contact time of 50 minutes, and SiNP dosage of 0.15 g vol−1. In addition, nitrate ion removal based on SiNPs will provide considerate benefits such as the reducing costly sample pretreatment steps, less time-consuming, and reliable methods for processing nitrate-polluted water.

A heterojunction photocathode of CuO and CuBi2O4 grown on an FTO substrate (FTO/CuO/CuBi2O4) was synthesized using hydrothermal method followed by spin coating and annealing to overcome the bottlenecks encountered by CuO in photoelectrochemical (PEC) water splitting application. The synthesis methods, morphological, structural properties, and composition of each sample under each synthesis condition are discussed in detail. The photocathode with 15 coating layers annealed at 450 °C exhibited the best PEC performance. Moreover, its current density reached 1.23 mA/cm2 under an applied voltage of − 0.6 V versus Ag/AgCl in a neutral electrolyte. Additionally, it exhibited higher stability than the bare CuO thin film. The bonding of CuBi2O4 on CuO resulted in close contact between the two semiconductors, helping the semiconductors support each other to increase the PEC efficiency of the photocathode. CuO acted as the electron-generating layer, and the CuBi2O4 layer helped minimize photocorrosion as well as transport the carriers to the electrode/electrolyte interface to accomplish the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

In this study, nitrogen-doped nickel graphene core cells (N-NiGR) are synthesized using the thermal chemical vapor deposition method. The structural, morphological, and chemical composition properties of N-NiGR are investigated using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. N-NiGR has shown potential as a material that can assist charge carrier transportation in the photoactive a layer of planar hybrid solar cell (PHSC) owing to its high charge carrier mobility and stability with the solution process. Here, we investigated for the first time an enhancement of the solar cell efficiency (by up to a 2% increase) in PHSCs by incorporating the charge selective N-NiGR into the device's photoactive layer. Synthesized N-NiGR with different concentrations are incorporated into the active layer of the devices as charge transport material. The device structure of an ITO-coated glass/Hole transport layer/(PBT7+N-NiGR+SnS)/Electron transport layer/Cathode is fabricated and the maximum power conversion efficiency of the device was observed to be about 4.35%. [ABSTRACT FROM AUTHOR]

Cu/Cu2O powder nanocomposites (PNCs) were successfully synthesized by colloidal solution method. To investigate the influence of oxidant agent concentration on the crystallite size and lattice constant of the PNCs, X-ray diffraction (XRD) was utilized to collect the database for crystal growth analysis. Due to the imperfect crystal growth, the Nelson-Riley function and the Williamson-Hall method were used to confirm the precise values of the PNCs. The Rietveld refinement method based on the XRD pattern was used. The XRD results show that the diffraction peaks were mainly assigned to the cubic structure, in good agreement with the ICDD standards. Furthermore, the change in oxidant agent concentration led to a very small change of microstrain in the peaks of Cu/Cu2O PNCs. Using these methods can aid in the precise study of the crystalline structure of the material, which can then be calculated to adjust the influencing conditions during the synthesis of the material. [ABSTRACT FROM AUTHOR]

The photocatalytic removal of water contaminants for ecological systems has become essential in the past few decades. Consequently, for commercialization, cost-efficient, earth-abundant and easy to synthesize photocatalysts for dye degradation are of urgent need. We have demonstrated a simple and feasible approach for fabricating TiO2–SnO2 nanocomposite photocatalysts via urea-assisted-thermal-decomposition with different mass ratios. The as-synthesized materials were characterized by different physicochemical techniques. The phase formation and crystallite size were calculated by using XRD. The STEM, UV-Vis, DRS, HR-TEM and EDS revealed the effective formation of the heterojunction between TiO2 and SnO2, and enrichment in the UV-absorption spectrum. All synthesized materials were used for the photocatalytic degradation of methyl orange (MO) under UV light. The optimized results of the TiO2–SnO2 nanocomposite showed excellent photostability and photocatalytic activity over a number of degradation-reaction cycles of methyl-orange (MO) dye under the illumination of ultraviolet light. In addition, the recent method has great potential to be applied as a proficient method for mixed-metal-oxide-nanocomposite synthesis. [ABSTRACT FROM AUTHOR]

Summary: Elemental doping promises an efficient strategy to modify and optimize the performance of metal oxide photoanodes. Herein, we introduce a simple hydrothermal method to fabricate In‐doped ZnO thin films on the fluorine‐doped tin oxide (FTO) to use as a photoanode for water splitting application. The effects of In‐doping on the structural, optical, morphological, and electrical properties of ZnO nanorods were studied. PEC results indicate that the 5% In doped ZnO photoanode determined an outstanding photocurrent density reached 0.42 mA/cm2 at 0.64 VAg/AgCl, which is four times higher than the undoped ZnO sample (0.1 mA/cm2). Furthermore, Ultraviolet‐visible spectroscopy (UV‐Vis) and photoluminescence spectroscopy (PL) studies showed a red‐shift in the band edge of doped samples compared to the pure samples, which indicate that the light absorption is enhanced. We find that the optimal doping of In (5%) leads to smaller charge transfer resistance and higher electron transfer rate as confirmed from EIS analysis. Therefore, fabricated In‐doped ZnO could be a favorable and potential photoelectrode for light‐harvesting and water splitting application. [ABSTRACT FROM AUTHOR]

We successfully synthesized Cu/Cu2O nanocomposites using the wet chemical synthesis method. All X-ray diffraction (XRD), Reference Intensity Ratio (RIR), and Rietveld refinement methods confirmed that the compounds Cu and Cu2O are free of impurities. Scanning Electron Microscope (SEM) and Transmission electron microscopy (TEM) images show the morphology and interactions of Cu and Cu2O in the structure. The formation mechanism is also explained by five stages: precursor, nucleation, growth, aging, and reduction. The changes in crystallization parameters under variations in reaction temperature (Tv) and stirring speed (Sv) were confirmed by agreement with the XRD database. The lattice constant in the crystal of nanocomposite increases with rising temperature in the reaction, leading to unit cell expansion, while increasing the stirring—rate leads to a random size distribution of the lattice parameter. Due to the imperfect growth of the crystal, the induced crystallite size was calculated using the Williamson-Hall model, and the precise lattice parameter values were calculated using the Nelson-Riley function. [ABSTRACT FROM AUTHOR]