Affiliation:
1. Chemical and Materials Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah 21589, Saudi Arabia
Abstract
Silver catalysts supported on ceria-zirconia (CZ) mechanically mixed oxide were synthesized by wet impregnation and chelating methods. Nominal loadings of 5 wt.% of Ag was deposited on the CZ support. These catalysts were tested for the CO2 hydrogenation reaction to methanol
with feed gas composition of CO2–H2 = 3:1 at 250 °C, 20 bar total pressure and GHSV of 1800 h−1. The calcined and reduced catalysts were characterized using XRD, BET, TPR, SEM-EDS, XPS and FTIR-DRIFTs techniques. Finely deposited silver crystallites
sized in the range of 20–50 nm were observed through SEM and HR-TEM analysis. TPR and XRD studies demonstrated the presence of Ag2O and metallic silver (Ag0) on CZ support. About 10% of CO formation was observed on chelating catalyst (5Ag/CZ CHE). However, only,
5% CO was observed on impregnated (5Ag/CZ IMP) catalyst. The greater CO formation was associated with ease reduction of Ag2O to metallic silver in 5Ag/CZ CHE catalyst. Further, 70% of methanol selectivity was observed on 5Ag/CZ IMP due to the presence of Ag2O on CZ. FTIR-DRIFTs
results revealed the methanol formation via formate intermediates and CO formation via RWGS reaction on the studied catalysts.
Publisher
American Scientific Publishers
Subject
Condensed Matter Physics,General Materials Science,Biomedical Engineering,General Chemistry,Bioengineering
Cited by
7 articles.
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