Sharif Digital Repository

In present study, an efficient method was used to synthesis Au and Pt nanoparticles on Ni modified MoS2 (MNi/MoS2 (M = Au and Pt). The morphology and structure of the prepared products were characterized using different microscopic and spectroscopic methods. The as-synthesized MNi/MoS2 nanocomposites were applied for catalytic reduction of p-nitrophenol (P-NP) in the presence of NaBH4. P-NP is one of the prevalent contaminants in wastewaters, while its corresponding aromatic amine (4-aminophenol) is a precious intermediate for manufacturing of important materials such as pharmaceuticals. The obtained catalytic results indicated that noble metal nanoparticles significantly affect catalytic... 

A series of Cr-substituted Fe-Ti compounds were prepared by the co-precipitation method and were systematically investigated as catalysts for the selective catalytic reduction (SCR) of NO by NH 3. A variety of analytical techniques revealed that the Cr substitution amount affects the N 2 selectivity, SCR activity, redox behavior of NH 3/NO x, adsorption ability, and structure of catalysts in terms of surface properties, porosity, mobility of lattice oxygen, oxidative ability of Cr species, ratio of Bronsted acid sites and Lewis acid sites, NO x adsorption capacity, and structural disorder and distortion. In a series of Fe aCr 1-aTiO x (a = 1, 0.75, 0.5, 0.2, 0) catalysts, Fe 0.5Cr 0.5TiO x... 

The present work reports the synthesis of a Pt-modified NiO–Al2O3 nanocomposite derived from graphene-supported layered double hydroxide (Pt–NiO/G) and demonstrates its catalytic activity. The resulting Pt–NiO/G nanocomposite was characterized by FT-IR, XRD, FE-SEM, TEM and XPS techniques and used for catalytic reduction of p-nitrophenol (P-NP) to p-aminophenol (P-AP). The influence of graphene on catalytic activity was comparatively considered by preparation of Pt–NiO nanoparticles derived from layered double hydroxide. The superior catalytic performance of Pt–NiO/G was ascribed to the synergistic effect between Pt and NiO. Furthermore, reduction of P-NP was considered to follow a... 

Metal Organic Frameworks (MOFs) have received enormous attention in catalysis field due to their special structures and various promising applications. One of the intriguing applications of MOFs is utilization of them as precursors for synthesis of metal oxide nanomaterials. Base on this strategy, in this work, we have applied Cu-MOF to prepare a series of noble metal nanoparticles (Ag and Au) decorated CuO (M/CuO) as efficient catalyst. As-prepared nanocomposites were characterized by various analytical techniques and their catalytic performances appraised by using of the catalytic reduction of p-nitrophenol to p-aminophenol as a reliable model reaction. Experimental results suggest that... 

Various challenging pollutants are produced in the environment by organic materials of diverse industries including leather, paint, and textile. Nowadays, it is vital to develop efficient manners regarding the fundamental issues and removing pollutants. Such pollutants can be effectively removed from the environment through heterogeneous catalysts. Recently, a huge deal of interest has been attracted by hydrogel-based metal catalysts as heterogeneous and efficient catalysts. In this regard, silver with its unique features is suitable for environmental remediation. Hence, the present review deals with summarizing the present advances in the synthesis of silver-based hydrogel catalysts, as... 

The metal sulfides with highly negative reduction potential and long life-span of photocreated electrons are conducive to being exceptional candidates for CO2 photoreduction, whereas they suffer from self-photo-oxidation (or photocorrosion) that puts the greatest impediment to their practical application. Up to now, the Z-type strategy is stated as a favorable solution to overtake photocorrosion of metal sulfides, while the eligible choice for coupling with these materials is still challenging. TiO2 with more negative onset potential holds favorable inherent peculiarities over other materials, which produces overlapped potential with various ranges of metal sulfides. In this investigation,... 

The significance of aromatic amines as crude substances in diverse applications has attracted extensive consideration in the field of economic procedures for the reduction of nitroarenes. Also, the formation of Carbon–Carbon bond as a dominant step in the structure of complex molecules is an important phenomenon in chemical reactions. Improvements of eco-friendly methodologies for reduction process and Carbon–Carbon bond formation have been noticeable. The present work represents through a capable heterogeneous Pd catalyst, the reduction of nitroarenes to the corresponding amines in the presence of N2H4 as a weak hydrogen donor reagent in the room temperature and solvent-free condition was... 

Copper-palladium alloys of different compositions are electrodeposited on nickel from aqueous solutions. These alloys are characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The catalytic activity of these alloys toward oxygen reduction reaction (ORR) in alkaline solution is investigated using rotating disk electrode (RDE). The number of electrons transferred per O2 molecule (n) obtained at different potentials is close to 2 at low overpotential indicating HO2- formation and gradually increases to 4 at higher overpotentials indicating full reduction to OH-. It is shown that Cu-Pd alloys are better electrocatalysts than Pd with Pd-Cu-1 having 24.5%... 

Due to the high activity of Au nanoparticles (NPs) for various reactions, many researchers have tried to develop heterogeneous catalysts in order to prevent irreversible agglomeration of Au NPs. Herein, magnetic graphene oxide modified with polyaniline (PANI) was used as a support for Au NPs that brings together advantages including: uniform dispersal of the catalyst in water,alarge surface area related to the graphene oxide; easy electron transfer in chemical reactions and good attachment of Au NPs to the support associated with PANI; and finally facile recovery in the presence of a magnetic field. Catalytic reduction of different analytes (Congo red, methylene blue, rhodamine B and 4-nitro... 

Selective catalytic reduction (SCR) of NOx by NH3 over a series of Mn–M/Z catalysts (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, and Z = the ZSM-5 Zeolite) synthesized by wet impregnation method was investigated. Mn–Fe/Z, Mn–Co/Z, and Mn–Cu/Z catalysts exhibited approximately 100 % NOx conversion over a wide temperature range (200–360 °C) in a defined atmospheric condition, which was noticeably greater than that of Mn–Cr/Z (340–360 °C). Furthermore, the effect of addition of second metal oxide species to the initial Mn/Z catalyst on the structure of catalysts was studied by several characterization techniques. BET measurements revealed high surface area and pore volume of the Mn–Cu/Z catalyst. In... 

Removal of dissolved oxygen (DO) from water has gained much attention in recent decades to prevent different problems such as corrosion, bio-fouling, and performance degradation in many industries. The traditional physical and chemical methods for DO removal have found wide application in industries. However, physical methods have low efficiency and chemical methods often produce undesirable products. Therefore, catalytic reduction by hydrogen has been regarded by a variety of industries recently. In this study, catalytic reduction of DO from water is examined using membrane reactors. The mathematical model of this system is developed while considering the axial dispersion, membrane... 

The catalytic reduction of dissolved oxygen (DO) from water was examined using membrane reactors and a mathematical model that considers axial dispersion, membrane permeation, and chemical reaction. The model is solved in steady state mode and the effect of various parameters on the DO removal was assessed. The results of steady state mode were employed as initial conditions for solving the model in dynamic mode. The impact of operating conditions, e.g., water flow rate, DO concentration of influent water, hydrogen flow rate, and hydrogen pressure on the performance of the DO process was studied. Results of the dynamic simulation suggested that hydrogen pressure is the best option to be used... 

This study investigates the synthesis of CuCo2O4, BiVO4, and CuCo2O4/BiVO4 nanocomposite by the solvothermal method. The Physico-chemical properties of the samples were verified through Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Transmission Electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET). Evaluation of catalytic efficiency of the synthesized samples were done in promoting the 4-Nitrophenol reduction to 4-Aminophenol in the existence of high amount of sodium borohydride (NaBH4) as a reducing agent, and the progress of the catalytic reaction was monitored... 

A novel sulfoxide containing bis(ether amine) monomer, 2,2'-sulfoxide- bis[4-methyl(2-trifluoromethyl)4-aminophenoxy) phenyl ether] (M2), was synthesized from the halogen displacement of 2-chloro-5-nitrobenzotrifluoride with dibenzosulfoxide (DH) in the presence of potassium carbonate, followed by catalytic reduction of bis(ether nitro) intermediate with Zinc/Ammonium chloride. A series of organic-soluble poly(ether amide)s (PA1-7) bearing sulfoxide and electronwithdrawing trifiuoromethyl group were synthesized from bis(ether amine) with various aromatic diacids (1-7) via a direct polycondensation with triphenyl phosphite and pyridine. The resulting polymers had inherent viscosities ranging...