کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5351141 | 1503649 | 2014 | 9 صفحه PDF | دانلود رایگان |
- Heterogeneous cobalt catalysts were synthesized from agricultural biomass.
- Cobalt catalysts were highly dispersed and exhibited good textural properties.
- The catalysts were active in the oxidation of phenol at ambient condition.
- The catalysis of cobalt catalysts was truly driven by its heterogeneous nature.
- RH-10Co was stable even after five consecutive catalytic runs.
Highly mesoporous cobalt silica rice husk catalysts with (5-15Â wt.%) Co2+ loading were prepared via a simple sol-gel technique at room temperature. The successful insertion of cobalt ions into silica matrix was evidenced from FT-IR, NMR, XPS and AAS analyses. Preservation of the mesoporosity nature of silica upon incorporating Co2+ was confirmed from the N2-sorption studies. The topography and morphology viewed by TEM analysis differs as the cobalt concentration varies from 5 to 15Â wt.%. Parallel pore channels and spherical nanoparticles of 9.44Â nm were achieved for cobalt silica catalysts with 10 and 15Â wt.% respectively. Cobalt catalysts were active in the liquid-phase oxidation of phenol with H2O2 as an oxygen source. The performances of the catalysts were greatly influenced by various parameters such as reaction temperature, catalyst amount, molar ratio of substrate to oxidant, nature of solvent, metal loading and homogeneous precursor salt. Water served as the best reaction medium for this oxidation system. The regeneration studies confirmed cobalt catalyst could be reused for five cycles without experiencing large loss in the conversion. Both leaching and reusability studies testified that the catalysts were truly heterogeneous.
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Journal: Applied Surface Science - Volume 315, 1 October 2014, Pages 154-162