Catalytic CO2 hydrogenation to higher hydrocarbons has become an approach to reduce both CO2 emission and dependence on fossil fuels. This research aims at developing the catalyst for CO2 hydrogenation to higher hydrocarbons especially C5+ products. The titania-supported monometallic and bimetallic Fe-based catalysts were prepared by co-wet impregnation method and tested for CO2 hydrogenation in a fixed-bed flow reactor (H2:CO2 = 3:1, 573 K and 1.1 MPa). Among the monometallic catalysts, only Fe/TiO2 catalyst exhibited selectivity to higher hydrocarbons. Co/TiO2 gave much higher CO2 conversion (55%) than Fe catalyst (16%), but only gave CH4 as the dominant product. Cu/TiO2 only produced CO as a main product, indicating the activity for reverse water gas shift. The combination of Fe and a small amount of second metal (Co and Cu) can enhance the CO2 conversion and the space-time yields (STY) of hydrocarbons. However, these bimetallic Fe-Co/TiO2 and Fe-Cu/TiO2 are still not selective for higher hydrocarbons product due to high CH4 formation. The cooperation of K and La addition as a promoter can improve activity and selectivity to higher hydrocarbons. Adding K can suppress the CH4 formation and also give higher olefin content of C2-C4 hydrocarbons. However excess K addition leads to more unhydrogenated CO. On the other hand, La can significantly shift CO toward C5+ hydrocarbons product through CO-FTS reaction pathway. Among all the catalyst combination, Fe-Cu/La/K/TiO2 catalyst has given highest STY of C5-7 hydrocarbons and minimized CH4 selectivity which is promising for liquid-fuel production from CO2 hydrogenation.

Fe-based bimetallic catalysts supported on TiO2 for selective CO2 hydrogenation to higher hydrocarbons

254th National Meeting (2017)

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