In the present study, magnet silica-coated Ag2WO4/Ag2S nanocomposites (FOSOAWAS) were fabricated via a multistep method to address the drawbacks related to single photocatalysts (pure Ag2WO4 and pure Ag2S) and to clarify the significant influence of semiconductor heterojunction on the enhancement of visible-light-driven organic degradation. Different techniques were performed to investigate the elemental composition, morphology, magnetic and photoelectrochemical properties of the fabricated FOSOAWAS photocatalyst. The FOSOAWAS photocatalyst (1 g/L) exhibited excellent photodegradation efficiency (99.5%) against Congo red dye (CR = 20 ppm) after 140 min of visible-light illumination. This result confirmed the ability of the heterojunction between Ag2WO4 and Ag2S species to improve the efficiency of the photogenerated electron/hole pair separation and to reduce their recombination. The kinetics studies of CR photoreaction suggested that the photodegradation rate of the FOSOAWAS photocatalyst was 3.26 and 2.94 times higher than that of pure Ag2WO4 and Ag2S NPs, respectively. The CR dye was investigated under various operating conditions (FOSOAWAS dosage, CR concentration, and pH of solution). The trapping experiments proved the significant roles of H2O2, •OH, and h+ oxidants in the photoreaction of CR dye. The proposed mechanism explains that the Type I heterojunction between Ag2WO4 and Ag2S semiconductors was responsible for the improved photocatalytic activity of the FOSOAWAS nanocomposite. Finally, the reusability and stability experiments proved the sufficient stability and facile separation of FOSOAWAS heterojunction, which may be employed in practical applications.
Vacuum gas oil (611-833)K was distilled from Kirkuk crude oil, which was obtained by blending the following fraction,
light vacuum gas oil (611 - 650) K, medium vacuum gas oil (650-690)K, heavy vacuum gas oil (690-727)K and very
heavy vacuum gas oil (727-833)K.
The vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified
condition in a laboratory trickle bed reactor. The reaction temperature varied from (583-643)K over liquid hourly space
velocity ranging between (1.5-3.75)h-1 , Hydrogen pressure was kept constant at 3.5 MPa with a hydrogen to oil ratio
of about 250 L/L
The conversion results for desulfurization appeared to obey the second order kinetics. According to
The performance of H2S sensor based on poly methyl methacrylate (PMMA)-CdS nanocomposite fabricated by spray pyrolysis technique has been reported. XRD pattern diffraction peaks of nano CdS has been indexed to the hexagonally wurtzite structured The nanocomposite exhibits semiconducting behavior with optical energy gap of4.06eV.SEM morphology appears almost tubes like with CdS/PMMA network. That means the addition of CdS to polymer increases the roughness in the film and provides high surface to volume ratio, which helps gas molecule to adsorb on these tubes. The resistance of PMMA-CdS nanocomposite showed a considerable change when exposed to H2S gas. Fast response time to detect H2S gas was achieved by using PMMA-CdS thin film sensor. The
... Show MoreIn this work, a novel design for the NiO/TiO2 heterojunction solar cells is presented. Highly-pure nanopowders prepared by dc reactive magnetron sputtering technique were used to form the heterojunctions. The electrical characteristics of the proposed design were compared to those of a conventional thin film heterojunction design prepared by the same technique. A higher efficiency of 300% was achieved by the proposed design. This attempt can be considered as the first to fabricate solar cells from highly-pure nanopowders of two different semiconductors.
Accurate description of thermodynamic, structural, and electronic properties for bulk and surfaces of ceria (CeO2) necessitates the inclusion of the Hubbard parameter (U) in the density functional theory (DFT) calculations to precisely account for the strongly correlated 4f electrons. Such treatment is a daunting task when attempting to draw a potential energy surface for CeO2-catalyzed reaction. This is due to the inconsistent change in thermo-kinetics parameters of the reaction in reference to the variation in the U values. As an illustrative example, we investigate herein the discrepancy in activation and reaction energies for steps underlying the partial and full hydrogenation of acetyl
... Show MoreIn this paper, we derive and prove the stability bounds of the momentum coefficient µ and the learning rate ? of the back propagation updating rule in Artificial Neural Networks .The theoretical upper bound of learning rate ? is derived and its practical approximation is obtained
Elastic magnetic electron scattering form factors in Ca-41 have been investigated. 1f7/2 subshell has been adopted as a model space with one neutron, and Millinar, Baymann and Zamick 1f7/2 model space effective interaction (F7MBZ) has been used as a model space effective interaction to generate the model space vectors for the M1, M3, M5, M7, and total form factors. Discarded space (core and higher configuration orbits) have been included through the first order perturbation theory to couple the partice-hole pair of excitation with 2ћω excitation energy in the calculation of the form factors and regarding the realistic interaction density dependence M3Y as a core polarization interaction with five sets of modern fitting parameters. Fina
... Show More