Effect of preparation of Fe-Zr-K catalyst on the product distribution of CO2 hydrogenation

The precursors of Fe-Zr-K catalysts were prepared by microwave assisted homogeneous precipitation followed by incipient wetness impregnation. The obtained mesoporous particles were small and uniformly shaped. After reduction, the catalyst showed high activity for the selective production of light olefins from CO 2 hydrogenation, superior to the catalyst obtained by co-precipitation. Characterization indicated that with Zr addition, the reducibility, surface basicity and surface atomic composition of the samples varied with the Zr content. The CO 2 adsorption ability of the samples was increased and the samples became hard to reduce as a result of the interaction between iron species and zirconia. In the case of using 5Fe-1Zr-K under selected conditions of 1000 h −1 , 320 °C and 2 MPa, the CO 2 conversion and the selectivity of C 2 -C 4 olefins reached 54.36% and 53.63%. The olefin/paraffin ratio in the C 2 -C 4 hydrocarbon product fraction reached 6.44. The selectivity of CO and C 5 + hydrocarbons were 3% and 19.78%, respectively. The catalytic activity remained stable up to 92 h in time-on-stream reaction. Small and uniform Fe-Zr-K particles with mesopores obtained by microwave assisted homogeneous precipitation show high catalytic activity and stability for the selective production of light olefins with low CO from CO 2 hydrogenation.