Sara Faiz Hanna Tasfy

Effects of Nb Promoter on the Properties of Cu/ZnO/SBA-15 Catalyst and Performance in Methanol Production

Hydrogenation of CO2 provides an alternative route for methanol production and attractive option for CO2 utilization. The present work investigates the synthesis of Cu-based catalyst on mesoporous silica (SBA-15) and promotion of the Cu-based catalyst with niobium (Nb). The addition of Nb promoter enhanced the reducibility and dispersion of the active sites as well as increased the BET and Cu surface areas. The performance of the synthesized catalyst in the hydrogenation of CO2 was evaluated in a fixed-bed microreactor at 523K, 22.5bar and H2/CO2 of 3. The CO2 conversion using the Cu/ZnO/SBA-15 catalyst was 14.2 % and increased to 17.1% on the Nb-promoted catalyst. The yield of methanol obtained using the un-promoted Cu-based catalyst was 51.4 g/h.gcat and it increased to 143 g/h.gcat over the Nb-promoted catalyst.

The role of support morphology on the performance of Cu/ZnO-catalyst for hydrogenation of CO2 to methanol

The effects of SBA-15 support morphology on the activity of Cu/ZnO catalyst in the hydrogenation of CO2 to methanol was investigated. In the hydrogenation of CO2 to methanol at 210°C, 2.25 MPa, H2/CO2 ratio of three remarkable difference was obtained using Cu/ZnO catalyst supported on SBA-15 with different morphology. The catalysts were characterized using N2-adsorption, field emission scanning microscopy (FESEM/EDX), transmission electron microscopy (HRTEM), and temperature-programmed reduction (TPR). Characterization of the catalyst showed that support morphology, surface area, metals dispersion, and reducibility influenced the catalytic performance. On the fiber-shaped SBA-15, copper dispersion was 29 % whereas on the spherical-shaped SBA-15, the dispersion was 20 %. The experimental results showed that the catalyst supported over fiber-shaped SBA-15 exhibit higher CO2 conversion (13.96 %) and methanol selectivity (91.32 %) compare to catalyst supported over spherical-shaped SBA-15.

Morphology and performance of Cu/ZnO based catalyst: Comparison between Al2O3 and SiC support

The effect of textural properties and morphologies of the support involving commercial alumina, Al2O3 and silicon carbide, SiC for copper-zinc oxide, Cu/ZnO based catalyst on the performance of carbon dioxide, CO2 hydrogenation to methanol, CH3OH was investigated. Using the same reaction condition at 2.25 MPa, 483 K, and the gas feed volume of CO2 to H2 ratio of 1:3, remarkable difference in terms of CO2 conversion and methanol selectivity were obtained using these two different supports. Copper and zinc oxide loaded onto alumina and silicon carbide, denoted as CZA and CZS respectively were characterized using Brunauer-Emmet-Teller (BET) and their result showed that CZA and CZS BET surface area were lower compared to their respective unloaded support because of the pore blockage. The morphologies of catalysts were also characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The experimental data showed that CZA exhibit lower CO2 conversion of 10....

Effect of Mn and Pb Promoters on the Performance of Cu/ZnO-Catalyst in CO2 Hydrogenation to Methanol

The influences of Mn or Pb promoters on the catalytic performance of Cu/ZnO-SBA-15 catalyst in the methanol synthesis from CO2 hydrogenation were studied. The catalytic performances of the prepared catalysts were investigated in a stirred high pressure reactor under conditions of T = 483K, P = 2.25 MPa, and H2:CO2 = 3:1 (volume ratio). The experimental results showed that the promoted catalysts exhibited higher catalytic performance. The Mn promoted catalyst resulted in 36% of CO2 conversion and 67% of methanol selectivity, whereas the unpromoted catalyst showed 26% of CO2 conversion and 58% of methanol selectivity.

Effects of Cu and K Promoters on the Catalytic Performance of Iron-Based Nanocatalyst for Fischer-Tropsch Synthesis

Iron-based nanocatalyst was prepared via impregnation method on SiO2 support. The effects of promoters, namely, K and Cu, on the physical properties and catalytic performance in FTS have been investigated. The FTS performance of the synthesized nanocatalysts was examined in a fixed-bed microreactor at temperature of 523K, atmospheric pressure, 1.5 reactant ratio (H2/CO) and space velocity of 3L/g-cat.h. In FTS reaction, Cu promoter resulted in a lower CO conversion and C5+ hydrocarbons selectivity but higher selectivity to the lighter hydrocarbons (C1-C4) comparedto those obtained using the K promoter. Higher CO conversion (28.9%) and C5+ hydrocarbons selectivity (54.4%) were obtained using K as a promoter compared to that of Cu promoter. However, the K-promoted nanocatalyst resulted in a lower CO conversion but higher selectivity of the heavy hydrocarbons (C5+) compared to those obtained using the un-promoted nanocatalyst.

Methanol production via CO2 hydrogenation reaction: effect of catalyst support

In this project, Cu-based catalyst was synthesised via impregnation method on various supports such as Al2O3, Al2O3-ZrO2, SBA-15 and Al-modified SBA-15. Samples were characterised by N2 adsorption-desorption, field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), temperature-programmed desorption/reduction (TPD/R) and pulse chemisorption. The activity of the supported Cu-based catalyst was evaluated in a fixed-bed micro-reactor at 483 K, 2.25 MPa, and H2/CO2 ratio of 3 : 1. Our results showed that the nature of the oxide support influenced the physicochemical properties of the catalysts as well as the catalytic activity and product selectivity. The size of catalyst nanoparticles ranged from 9 nm to 37 nm, depending on the type of support used. The Cu-based catalyst supported on SBA-15 resulted in 13.96% CO2 conversion and methanol selectivity of 91.32% and these values were higher than those obtained using Cu-based catalyst supported on other oxide carriers.

Carbon Dioxide Hydrogenation to Methanol over Cu/ZnO-SBA-15 Catalyst: Effect of Metal Loading

Utilization of CO2 as a carbon source to produce valuable chemicals is one of the important ways to reduce the global warming caused by increasing CO2 in the atmosphere. Supported metal catalysts are crucial to produce clean and renewable fuels and chemicals from the stable CO2 molecules. The catalytic conversion of CO2 into methanol is recently under increased scrutiny as an opportunity to be used as a low-cost carbon source. Therefore, a series of the bimetallic Cu/ZnO-based catalyst supported by SBA-15 were synthesized via an impregnation technique with different total metal loading and tested in the catalytic hydrogenation of CO2 to methanol. The morphological and textural properties of the synthesized catalysts were determined by transmission electron microscopy (TEM), temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO), and N2-adsorption. The CO2 hydrogenation reaction was performed in a microactivity fixed-bed system at 250oC, 2.25 MPa, and H2/CO2 ratio of 3. Experimental results showed that the catalytic structure and performance were strongly affected by the loading of the active site. Where, the catalytic activity, the methanol selectivity as well as the space-time yield increased with increasing the metal loading until it reaches the maximum values at a metal loading of 15 wt% while further addition of metal inhibits the catalytic performance. The higher catalytic activity of 14% and methanol selectivity of 92% was obtained over a Cu/ZnO-SBA-15 catalyst with a total bimetallic loading of 15 wt%. The excellent performance of 15 wt% Cu/ZnO-SBA-15 catalyst is attributed to the presence of well dispersed active sites with small particle size, higher Cu surface area, and lower catalytic reducibility.

Hydrogenation of CO2 to methanol using copper/zinc oxide-based catalyst: Effect of active metal ratio

Effects of Cu:Zn ratio on the catalytic performance of synthesized SBA-15 supported Cu/ZnO-based (CZS) catalyst for the hydrogenation of CO2 to methanol was investigated in a fixed bed reactor. The physicochemical properties of the synthesized CZS catalyst in terms of textural properties, morphological and reducibility are presented. Methanol productivity was found to be influenced by the ratio of Cu and Zn in the catalyst formulation. Methanol selectivity of 92.1 % and CO2 conversion of 14.2 % was achieved over CZS catalyst with active metal ratio of 70 %Cu:30% Zn in CO2 hydrogenation reaction performed at 250°C, 2.25 MPa, and H2/CO2 ratio of 3.

The Influence of Mn, Zr and Pb Promoters on the Performance of Cu/ZnO/SBA-15 Catalyst for Hydrogenation of CO2 to Methanol

The present work investigates the hydrogenation of CO2 to methanol via a promoted Cu/ZnO/SBA-15 catalyst. In order to understand the effect of Mn, Zr and Pb promoters on the catalytic activity of Cu/Zn/SBA-15 catalysts, the hydrogenation of CO2 was performed in a stirred high-pressure reactor at 483K, 22.5bar, and a H2/CO2 ration of 3. The physicochemical properties of the catalysts were studied using N2 physical adsorption, TEM and H2-TPR. The characteristics of catalysts depended on the type of promoter and it influenced their catalytic performance. The Mn and Zr promoters resulted in a larger surface area of the catalyst and improved catalytic activity and methanol selectivity. However, an opposite effect was found for the Pb promoter. A 10% improvement on the CO2 conversion and 20% on the methanol selectivity was achieved due to the double promotion effect of Mn and Zr on Cu/ZnO-SBA-15 catalyst.

Morphological and textural properties of mesoporous silica synthesized under different conditions

This paper presents the synthesis and characterization of mesoporous silica prepared under various synthesis conditions. Variables studied were acidity, aging period, washing solvent, washing technique and drying temperature. The influence of these parameters on the textural properties and morphology of mesoporous silica is reported. Increasing the acidity of the synthesis solution changed the shape of the particles from spherical to rope-like fibers and also increased the BET surface area of the silica.