The utilization of CO

2

as rawmaterial for chemical synthesis has the potential for substantial economic and green benefits. Thermal decomposition of hexamethylene-1

6-dicarbamate (HDC) is a promising approach for indirect utilization of CO

2

to produce hexamethylene-1

6-diisocyanate (HDI). In this work

a green route was developed for the synthesis of HDI by thermal decomposition of HDC over Co

3

O

4

/ZSM-5 catalyst

using chlorobenzene as lowboiling point solvent. Different metal oxide supported catalysts were prepared by incipientwetness impregnation (IWI)

PEG-additive (PEG) and deposition precipitation with ammonia evaporation (DP) methods. Their catalytic performances for the thermal decomposition of HDC were tested. The catalyst screening results showed that Co

3

O

4

/ZSM-5

25

catalysts prepared by different methods showed different performances in the order of Co

3

O

4

/ZSM-5

25(PEG)

N Co

3

O

4

/ZSM-5

25(IWI)

N Co

3

O

4

/ZSM-5

25(DP)

. The physicochemical pr

operties of Co

3

O

4

/ZSM- 5

25

catalyst were characterized by XRD

FTIR

N

2

adsorption-desorption measurements

NH

3

-TPD and XPS. The superior catalytic performance of Co

3

O

4

/ZSM-5

25(PEG)

catalyst was attributed to its relative surface content of Co

3+

surface lattice oxygen content and total acidity. Under the optimized reaction conditions: 6.5% HDC concentration in chlorobenzene

1 wt% Co

3

O

4

/ZSM-5

25(PEG)

catalyst

250 ℃ temperature

2.5 h time

800 ml·min-1 nitrogen flow rate and 1.0 MPa pressure

the HDC conversion and HDI yield could reach 100% and 92.8% respectively. The Co

3

O

4

/ZSM-5

25(PEG)

catalyst could be facilely separated from the reaction mixture

and reused without degradation in catalytic performance. Furthermore

a possible reaction mechanism was proposed based on the physicochemical properties of the Co

3

O

4

/ZSM-5

25

catalysts.