The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system. The effects of ultra stable Y (USY)

Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygenation (

E

deoxygenation

)

lightweight (

E

lightweight

) from CTA pyrolysis volatiles were investigated. Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts

while the deoxygenation effect is determined by theirs pore size. The

E

lightweight

of CTA pyrolysis volatiles over USY is 9.65%

while the

E

deoxygenation

of CTA pyrolysis volatiles over Mo/USY reaches 20.85%. Additionally

the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production

owing to the synergistic effect of metal ions (Mo

Co) and acid sites of USY. Compared with the non-catalytic fast pyrolysis of CTA

t

he total yield of L-ArHs obtained over USY (4032 mg·kg

-1

)

Co/USY (4363 mg·kg

-1

) and Mo/USY (4953 mg·kg

-1

) were increased by 27.03%

38.19% and 54.78%

respectively. Furthermore

the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.