Potassium promoted iron-zinc catalysts prepared by co-precipitation method (C-Fe-Zn/K)

solvothermal method (S-Fe-Zn/K) and hydrothermal method (H-Fe-Zn/K) could selectively convert CO

2

to light olefins

respectively. The physicochemical properties of the obtained catalysts were determined by SEM

N

2

physisorption

XRD

H

2

-TPR

CO

2

-TPD and XPS measurements. The results demonstrated that preparation methods had great influences on the morphology

phase structures

reduction and adsorption behavior

and hence the catalytic performance of the catalysts. The samples prepared by hydrothermal and co-precipitation method generated small uniform particles and led to lower specific surface area. In contrast

microspheres with larger specific surface area were formed by self-assembly of nanosheets using solvothermal method. ZnFe

2

O

4

was the only detectable phase in the fresh C-2Fe-1Zn/K

S-3Fe-1Zn/K and S-2Fe-1Zn/K samples. ZnFe

2

O

4

and ZnO co-existed with increasing Zn content in S-1Fe-1Zn/K sample

while ZnO and Fe

2

O

3

could be o

bserved over H-2Fe-1Zn/K sample. All the used samples contained Fe3O4

ZnO and Fe

5

C

2

. The peak intensity of ZnO was strong in the AR-H-2Fe-1Zn/K sample while it was the lowest in the AR-C-2Fe-1Zn/K sample after reaction. The formation of ZnFe

2

O

4

increased the interaction between iron and zinc for C-2Fe-1Zn/K and S-Fe-Zn/K samples

causing easier reduction of Fe

2

O

3

to Fe3O4. The surface basicity of the sample prepared by co-precipitation method was much more than that of the other two methods. During CO

2

hydrogenation

all the catalysts showed good activity and olefin selectivity. The CO selectivity was increased with increasing Zn content over S-Fe-Zn/K samples. H-2Fe-1Zn/K catalyst preferred to the production of C

5

+

hydrocarbons. CO

2

conversion of 54.76% and C

2

=

-C

4

=

contents of 57.38% were obtained on C-2Fe-1Zn/K sample

respectively.