The deactivation of Ni/SiO

2

-Al

2

O

3

catalyst in hydrogenation of crude 1

4-butanediol was investigated. During the operation time of 2140 h

the catalyst showed slow activity decay. Characterization results

for four spent catalysts used at different time

indicated that the main reason of the catalyst deactivation was the deposition of carbonaceous species that covered the active Ni and blocked mesopores of the catalyst. The TPO and SEM measurements revealed that the carbonaceous species included both oligomeric and polymeric species with high C/H ratio and showed sheet. Such carbonaceous species might be eliminated through either direct H

2

reduction or the combined oxidation-reduction methodologies.