Synthesis and Characterization of CoMo/Zn–Al Mixed Oxide Catalysts for Hydrodesulphuration of Thiophene

Abstract

New CoMo/Zn-Al mixed oxide catalysts were synthesized, characterized and tested in the HDS reaction of thiophene. Catalytic supports were synthesized by using variable (Al)/(Al ? Zn) mol ratios from 0.0 to 1.0, then, these supports were calcined up to 450°C and finally impregnated with Mo and Co, and calcined at 450°C again. Before impregnation, these solids were characterized by XRD and FT-IR, and after impregnation, by BET surface area measurements and temperature programmed reduction (TPR). Results showed that the hydrotalcite phase is formed between 0.20 and 0.33 (Al)/(Al ? Zn) mol ratios. At increasing Al content, an Al 2 O 3 phase (b-Al 2 O 3 ) emerges together with the hydrotalcite phase which diminishes as Al content increases. Results corresponding to the thiophene HDS reaction showed a catalytic activity maximum at 0.25 ratio; then, the catalytic activity decreased with Al content. These results could be associated with an optimum combination of Al and Zn oxides in which their properties are complemented.

Ni/ZnO-based Adsorbents Supported on Al2O3, SiO2, TiO2, ZrO2: A Comparison for Desulfurization of Model Gasoline by Reactive Adsorption

“…Therefore, another shoulder peak with T max at around 460°C in the profile of Ni/ZnO-Al 2 O 3 can be assigned to the reduction of Ni (tetra). The broad peak in the four samples (within about 500 °C and 700 °C) could correspond to the reduction of ZnO species on the solid surface which is consistent with the conclusion of Barroso et al 24 and Ruth et al 25 It is observed that the reduction of Ni/ZnO-Al 2 O 3 hasn't completed even when the temperature up to 800 °C, which can be related to the spinel species like ZnAl 2 O 4 , and the presence of ZnAl 2 O 4 is also confirmed by XRD Characterization. The results imply that the formation of spinel species can reduce the reducibility of adsorbent.…”

Hydrogenation of Ethyl Acetate to Ethanol over Bimetallic Cu-Zn/SiO2Catalysts Prepared by Means of Coprecipitation

“…With the increasing loading of Zn, the crystallite size of Cu changed. 33 The XRD result in Figure 3 confirmed that characteristic structure in Cu 4 Zn 0 Si 4 and Cu 2 Zn 2 Si 4 remained after calcination and no separated ZnO could be detected. XRD results (Figures 4 and 5) show the presence of only metallic copper after the reduction of catalysts at 300 o C and it well conform to the TPR results.…”

Applications of CoMo/calcined quaternary hydrotalcites for hydrotreatment reactions

“…Rana et al [12] found that the incorporation of MgO to Al 2 O 3 by preparation of hydrotalcites, favors the hydrogenolysis of dibenzothiophene (DBT) when it is compared to a traditional catalyst (CoMo/γ-alumina). Álvarez et al [13] synthesized hydrotalcites with variable Al/(Al + Zn) mol ratio from 0 to 1. Catalysts were tested in HDS of thiophene.…”