Seyed Ali Hosseini

Chemical-physical properties of spinel CoMn2O4 nano-powders and catalytic activity in the 2-propanol and toluene combustion: Effect of the preparation method

Spinel-type CoMn2O4nano-powders are prepared using sol-gel auto combustion (SGC) and co-precipitation (CP) methods and their catalytic activities are evaluated in combustion of 2-propanol and toluene. The chemical-physical properties of the oxides are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2-adsorption-desorption, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). After calcination at 700°C, CoMn2O4-SGC shows higher amounts of the normal-type spinel phase and is more crystalline than CoMn2O4-CP. Higher calcination temperatures (850°C) do not affect very much the weight percentage of the normal-type spinel phase; although the crystal size slightly increased. The TPR analysis evidences a large number of Mn3+ cations in CoMn2O4-SGC compared to CoMn2O4-CP. This difference, together with the higher surface area, could justify the higher activity of CoMn2O4-SGC in both the investigated reactions.

Synthesis,Characterization,and Performance of LaZnxFe1-xO3 Perovskite Nanocatalysts for Toluene Combustion

Nanostructured LaFeO3 and substituted LaZnxFe1-xO3 (x = 0.01, 0.05, 0.1, 0.2, and 0.3) perovskites were synthesized by the sol-gel auto-combustion method and used in the catalytic combustion of toluene. Their structures and surface properties were investigated by X-ray diffraction, Fourier transmission infrared spectroscopy, BET surface area, and scanning electron microscopy. Characterization data revealed that the total insertion of zinc into LaFeO3 takes place when x ≤ 0.1. However, ZnO segregation occurs to some extent, especially at x > 0.1. The performance of these perovskites was evaluated by toluene combustion. The catalytic activity of the catalysts increased substantially with an increase in zinc substitution. These results can be attributed to the cooperative effect between LaZnxFe1-xO3 and the zinc oxide phases. The relative concentration of these phases determines their oxygen activation ability and reactivity.

Oxidation of ethyl acetate by a high performance nanostructure (Ni, Mn)-Ag/ZSM-5 bimetallic catalysts and development of an artificial neural networks predictive modeling

The catalytic oxidation of ethyl acetate in low concentration was investigated over mono-metallic Ag/ZSM5 and bimetallic (Ni, Mn)-Ag/ZSM-5 catalysts. Catalytic studies were carried out in a catalytic fixed bed reactor under atmospheric pressure. The sequence of catalytic activity was as follows: Ni-Ag-ZSM-5 > Mn-Ag-ZSM-5 > Ag-ZSM-5 > H-ZSM-5. The catalysts were characterized by ICP-AES, X-ray diffraction (XRD), low temperature nitrogen adsorption, NH3-TPD, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and diffuse reflectance UV–vis spectra (UV–vis). An artificial neural networks (ANN) model was developed to predict the performance of catalytic oxidation process over bimetallic Ni-Ag/ZSM-5 catalyst based on experimental data. For this purpose the standard feed forward back propagation algorithm was employed to train the model by using laboratory experimental data. A good agreement was resulted between experimental results and those obtained by ANN. Following order for variables effects on conversion yield of ethyl acetate was predicted by ANN model: reaction temperature (32.99%) > Ag loading (27.38%) > initial ethyl acetate concentration (23.58%) > Ni loading (16.05%).

Synthesis, Characterization, and Catalytic Activity of Nanocrystalline La1-xEuxFeO3 during the Combustion of Toluene

Abstract Nanostructured LaFeO 3 and substituted La 1- x Eu x FeO 3 ( x = 0.1, 0.15, and 0.2) perovskites were synthesized by sol-gel auto-combustion and their activities during the combustion of toluene were evaluated. The structure and physico-chemical properties of the perovskites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and BET surface area analyses. The compounds were crystallized as a perovskite phase with an orthorhombic structure. The mean particle size of the perovskites increased with an increase in europium loading while the specific surface area decreased. Characterization data confirmed that a total insertion of Eu into LaFeO 3 occurred at x ≤ 0.15. However, Eu 2 O 3 segregation occurred to some extent especially at x > 0.15. The catalytic activity of the catalysts increased substantially with an increase in Eu substitution in the evaluated range.

Catalytic remediation of 2-propanol on Pt-Mn/γ-Al2O3 bimetallic catalyst during catalytic combustion--experimental study and response surface methodology (RSM) modeling.

Process and composition variables of catalytic oxidation of 2-propanol on Pt-Mn/γ-Al2O3 bimetallic catalysts were optimized and modeled by response surface methodology (RSM). 31 factorial experiments were designed by setting four factors at five levels: X 1 = amount of manganese loading (wt.% Mn = 1, 3, 5, 7, 9); X 2 = reaction temperature (25, 50, 75, 100, 125°C); X 3 = calcination temperature (200, 300, 400, 500, 600°C) and X 4 = calcination time (2, 3, 4, 5, 6 h). A second-order polynomial model and response surface were developed for 2-propanol conversion. The optimum conditions for 2-propanol complete conversion were 4.8wt.% manganese loading, 4h calcination time with 75°C and 395°C for reaction and calcination temperatures, respectively. A good correlation was found between experimental and predicted responses, confirming the reliability of the model.