Sharif Digital Repository

The self-supported CuxNi0.6-xMn0.4Fe2O4 oxygen carrier (x = 0.1–0.5) is synthesized to be applied in the chemical looping steam methane reforming (CL-SMR) process through the synthesized co-precipitation method. The response surface methodology (RSM) based on the Box–Behnken model is adopted to evaluate the effects of independent variables on the functionality of responses as well as predicting the best response volume. In this method, the variables consisting of reaction temperature (550–700°C), oxygen carrier (OC) loading percentage (0.1–0.5), steam-to-CH4 ratio (S/C), (1.5–3.5), and redox cycles’ count (10–24) and the responses consisting of hydrogen (H2) production yield, CH4 conversion... 

In the present research, NiO–SDC (Samarium doped Ceria) nanopowder was synthesized through sol–gel combustion method using citric acid as a reducing agent (fuel) and metal nitrates as an oxidant. The characteristics of the synthesized powder were thoroughly analyzed by DTA/TG, XRD, BET and FESEM/EDX. Tubular gel-casted porous specimens of NiO–SDC (50:50 wt%) composite materials were produced after stabilizing suspensions of composite powder in an aqueous environment by addition of 3 wt% dispersant and 2.5 wt% agar as the gel builder. The effect of Dolapix CE64 as a dispersant, agar as a gel-builder and the amount of solid loadings on the processing and properties of porous ceramics was... 

Nowadays, the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material has attracted great research interest due to its high energy density and less usage of costly raw materials. However, the high nickel content of NCM811 brings about an extremely unstable interface between the electrode and electrolyte and therefore inferior cyclic stability. Herein, we have proposed a straightforward method to deliver 1, 2, and 4 wt % of TiO2 nanoparticles (NPs) on the surface of the NCM811 cathode material and to improve its properties at room and high temperatures. Based on scanning electron microscopy and transmission electron microscopy observations, the coating thickness varies from 10 to 35 nm and the 2 wt %... 

The development of efficient and cost-effective catalysts for the oxygen evolution reaction is highly desirable for applications that are based on sustainable and clean technologies. In this study, we report the synthesis of a series of cerium(iv) oxide and nickel diselenide nanocomposites (NiSe2/CeO2) as efficient electrocatalysts for the oxygen evolution reaction in an alkaline medium. The ratios of the two substances were optimized to reach the highest catalytic activity. The structure and morphology of synthesized materials were investigated by XRD, FE-SEM, EDX, BET, XPS, and TEM techniques. It was observed that the nanocomposite with a 10 : 1 mass ratio of NiSe2to CeO2showed the best... 

In this study, an attempt has been made using different concentrations of rare-earth (RE) elements Yb, Gd in Ni–Zn spinel ferrite to examine the magneto-optical and electrical conductivity analysis of the prepared samples. RE doped Ni–Zn ferrite with composition Ni0.5Zn0.5YbxGdxFe2-xO4 (where, x = 0.00, 0.20, 0.40, 0. 60, 0.80 and 1.00) were prepared by one step sol-gel self-ignition approach. XRD and FESEM were used to examine the formation of a single-phase and variations in the grain size with the increasing contents of RE elements in Ni–Zn ferrite NPs. FTIR confirmed the vibrational studies of the RE doped spinel ferrite. The saturation magnetization, remanence, and coercivity elucidated... 

NiZn nanoferrites doped with rare-earth cations having stoichiometric composition such as Ni0.5Zn0.5R0.02Fe1.98O4 (R = Tb, Pr, Ce, Gd, Y) were prepared by sol–gel technique. The same amount of Ni and Zn with constant ratio of different rare-earths ions were doped to investigate the variations in the properties. X-ray diffraction (XRD), Field emission electron microscope (FESEM), and vibrating sample magnetometer (VSM) were used to investigate the structure, morphology, and magnetic properties of rare-earth doped NiZn nanoferrites, respectively. X-ray density, bulk density, and porosity were also calculated. Phase, crystallite size, structure, d-spacing, lattice parameter, micro strain, and... 

In this study, an attempt has been made using different concentrations of rare-earth (RE) elements Yb, Gd in Ni–Zn spinel ferrite to examine the magneto-optical and electrical conductivity analysis of the prepared samples. RE doped Ni–Zn ferrite with composition Ni0.5Zn0.5YbxGdxFe2-xO4 (where, x = 0.00, 0.20, 0.40, 0. 60, 0.80 and 1.00) were prepared by one step sol-gel self-ignition approach. XRD and FESEM were used to examine the formation of a single-phase and variations in the grain size with the increasing contents of RE elements in Ni–Zn ferrite NPs. FTIR confirmed the vibrational studies of the RE doped spinel ferrite. The saturation magnetization, remanence, and coercivity elucidated... 

NiZn nanoferrites doped with rare-earth cations having stoichiometric composition such as Ni0.5Zn0.5R0.02Fe1.98O4 (R = Tb, Pr, Ce, Gd, Y) were prepared by sol–gel technique. The same amount of Ni and Zn with constant ratio of different rare-earths ions were doped to investigate the variations in the properties. X-ray diffraction (XRD), Field emission electron microscope (FESEM), and vibrating sample magnetometer (VSM) were used to investigate the structure, morphology, and magnetic properties of rare-earth doped NiZn nanoferrites, respectively. X-ray density, bulk density, and porosity were also calculated. Phase, crystallite size, structure, d-spacing, lattice parameter, micro strain, and... 

The high amount of base metals poses an important challenge in gold bioleaching from spent printed circuit boards (PCBs). This study aims to investigate the bioleaching of important base metals (Cu, Ni, and Fe) from a mixture of spent PCBs (E-waste) using adapted Acidithiobacillus ferrooxidans in the bubble column bioreactors. Firstly, the adaptation process is done from 1 to 15 g/L in Erlenmeyer flasks in 187 days, then the concentration of E-waste increased to 40 g/L in bubble column bioreactors in 44 days. The concurrent recovery of copper, nickel, and iron using adapted bacterium in a bioreactor was optimized by central composite design. Various effective parameters such as aeration... 

Organic-inorganic hybrid halide perovskite materials have been most attractive for wide range of optoelectronic applications. Investigating the photo-response in these devices will be very useful to understanding cell performance in different conditions and applications. For understanding non-linearity photo-response we use the Bathocuproine (BCP) as blocking layer in two interfaces of inverted perovskite solar cell (FTO/NiO/BCP/Perovskite/PCBM/Au and FTO/NiO/Perovskite/PCBM/BCP/Au). Employing thick BCP layer (≈15 nm) caused s-shaped JV curve due to charge accumulation at interfaces. The nonlinearity effect was also explored for devices with s-shaped JV and established that device parameters... 

The treatment facility of Albourz Industrial City was established in 1999 at the southeast of Albourz Mountain with an area of 200,000 square meters. Currently, 40,000 cubic meters of industrial wastes are treated daily utilizing biological method of activated sludge up to the second phase without chlorination in this treatment facility. Then, the discharged wastes are directed toward the lower agricultural lands. The environmental status of the region was investigated by testing the impact of wastewater and agricultural products in four tries. In two tries, the levels of COD and BOD were higher than the environmental standards, but there was no trace of heavy metal contamination in any of... 

Nickel oxide (NiOx) is a promising hole transport material in inverted organic-inorganic metal halide perovskite solar cells. However, its low intrinsic conductivity hinders its further improvement in device performance. Here, we employ a trimercapto-s-triazine trisodium salt (TTTS) as a chelating agent of Ni2+ in the NiOx layer to improve its conductivity. Due to the electron-deficient triazine ring, the TTTS complexes with Ni2+ in NiOx via a strong Ni2+-N coordination bond and increases the ratio of Ni3+:Ni2+. The increased Ni3+ concentration adjusts the band structure of NiOx, thus enhancing hole density and mobility, eventually improving the intrinsic conductivity of NiOx. As a result,... 

Novel Bi2S3/NiCo2O4 nanocomposites (BS/NCO) with various mass ratios were prepared using NiCo-MOF as precursor. The morphology, composition and structure of the as-prepared catalysts were studied by different techniques such as FE-SEM, EDX, XRD, FT-IR, VSM and BET. The as-synthesized composite with 20 % Bi2S3 (%20 BS/NCO) demonstrated the best performance in reduction reaction of 4-nitrophenol (4-NP). The enhanced catalytic activity of %20 BS/NCO composite compared to the Bi2S3 and NiCo2O4 can be assigned to the optimized synergistic effects between the two pristine materials. Thermodynamic parameters and the activation energy of the reaction in the presence of %20 BS/NCO composite were... 

The aim of this study is to investigate the role of the temperature, stress, and rhenium (Re) on the γ/γ' interfacial misfit dislocation network and mechanical response of Ni-based single crystal superalloys. After aging at elevated temperatures, mismatch between the two phases results in an interfacial dislocation network to relieve the coherency stress. Molecular dynamics (MD) simulations have been performed to study the properties of the (100), (110), and (111) phase interface crystallographic directions. Increasing temperature disperses the atomic potential energy at the interface diminishing the strength and stability of the networks. In the case of loading, when a constant strain rate... 

The productive and straightforward strategy was developed to fabricate graphene based NiFe2O4 doped rare-earth (RE) ions nanocomposites for enhancing the magnetic and structural characteristics of ferrites. RE nanoparticles (NPs) such as Yb3+, Gd3+ and Sm3+ were doped in NiFe2O4 ferrite structure via sol-gel auto-combustion method and hydrothermal method was utilized to fabricate their graphene-based nanocomposites. The weight loss and decomposition of the nanocomposites were determined using temperature-dependent thermo gravimetric analysis (TGA/DTA). The single-phase structure of the NiFe2O4, NiFe2O4/G, Yb doped NiFe2O4/G, Gd doped NiFe2O4/G, and Sm doped NiFe2O4/G nanocomposites was... 

In this contribution, NiO-MgO-SiO2 catalysts containing 3 wt. % of CeO2, La2O3, Y2O3, and Zr2O3 were examined for propane dry reforming at 550-750 °C. The samples were synthesized by a co-precipitation route, followed by a hydrothermal treatment, and characterized by BET, XRD and TPX analyses. The results indicated that the addition of promoters enhanced the metal-support interaction and basic characteristics, while the acidic nature of the promoted catalyst was changed in a different way. The highest propane conversion of 39.6% was observed over Ce-promoter sample, while the un-promoted catalyst possessed a value of 36.8% at 700 °C. Nevertheless, La and Y-promoted catalysts possessed a... 

Mobile phones are known as the most widely used electronic instruments, and an enormous number of discarded mobile phones are generated. The present work used a pure culture of Penicillium simplicissimum in a bubble column bioreactor to extract Cu and Ni from mobile phone printed circuit boards (MPPCBs) waste. Molasses was used as an efficient carbon source to enhance bioleaching efficiency and increase the cost benefits. The adaptation phase was done at Erlenmeyer flasks to reach 40 g/L of MPPCBs powder. The most significant parameters, including the mass of MPPCBs powder, aeration, molasses concentration, and their interaction, were optimized in order to leach the maximum possible Cu and... 

Methane steam reforming (MSR) is an assuring reaction using steam to produce H2 as clean energy over a nicκel-based catalyst. We synthesized mesoporous monometallic NiMgAl2O4 and bimetallic NiCoMgAl2O4 catalysts in a two-step combustion method using a mix of fuels and powder metallurgy. BET-BJH, XRD, TGA, TPR, FESEM, and EDX-mapping characterized surface area, porosity, morphology, crystalline structure, and metal-support interaction behavior. The products exhibited strong interaction of well-structured MgAl2O4 spinel with NiO, in both specimens. The MSR evaluation tests at 750 °C under atmospheric pressure, CH4:H2O feed ratio of 1:1.2 showed the bimetallic catalyst has the highest... 

Developing extremely efficient electrocatalysts for oxygen evolution reactions (OER) is a decisive step toward the progression of rechargeable metal-oxygen batteries, CO2 reduction, and water-splitting. Nanoporous high-entropy transition-metal sulfides (np-HETMS) represent a new generation of promising OER catalysts by virtue of their exceptional catalytic activity. However, their synthesis maintains to be a challenge by reason of the thermodynamic immiscibility of the constituting multi-principal metallic elements in the sulfide structure. Herein, for the first time, the np-HETMS ((CoFeNiMnCu)S2) nanoparticles with pyrite-phase was synthesized via a facile and easy adaptable... 

Here, a three dimensional nickel–based metal organic framework (MOF) was synthesized via solvothermal and room temperature protocols. In order to study the effects of the synthesis conditions on the physical properties such as pore sizes and shapes of the prepared MOFs, their extraction capabilities were examined. Both MOFs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller and thermogravimetric analyses. Brilliant properties such as porous structure, high surface area and considerable thermal stability make them reasonable candidates to be employed as efficient extractive phases. The efficiency of the...