Carbon Coating on SiO2 in Co/C-SiO2 Catalysts for High and Stable Activity in Nitrobenzene Hydrogenation

Since 5% Co/SiO2 catalysts exhibited good activity in nitrobenzene hydrogenation when compared other supported (Al-2 O-3, ZrO2, TiO2) catalysts(SI), effect of Co loading on SiO2 support against aniline synthesis was studied in vapour phase conditions. Variation of Co loading revealed that 5% Co/SiO2 is a better catalyst in terms of nitrobenzene hydrogenation activity. Smaller Co particle size with good number of active sites are helpful in exhibiting good activity by this catalyst. However this catalyst suffers activity loss after 7(th) hour due to coking. In order to sustain the activity for longer duration SiO2 surface was coated with carbon prior to deposition of Co and found that this Co/C-SiO2 catalyst exhibited high and steady activity during the time on steam study.