The texture properties as well as the carbon yields of the
prepared carbon samples are listed in Table 1. It is evident to see
that both impregnation ratio of ZnCl2/SSH and activation
temperature have significant impact on the surface area and pore
structure of the obtained activated carbons. At ZnCl2/SSH = 2, the
pore is dominantly microporous, whereas at ZnCl2/SSH = 3,
mesoporous structure occupies a much higher fraction of the
total pore volume. This result can be attributed to the coalescence
of micropore to form mesopore at higher ZnCl2/SSH ratio due to the
high release of volatile matters, which leads to the decrease of
micropore surface area and enhancement of mesopore surface area
[22]. However, unlike that reported by Liou [15], the BET surface
area of the samples prepared at ZnCl2/SSH = 3 does not drop with
the decrease of micropore surface area as compared to that
prepared at ZnCl2/SSH = 2. Instead, the highest specific surface area
of 2212 m2/g is achieved on S-3-550, the sample displays the
lowest micropore surface area of 381 m2/g but the highest
mesopore surface area of 1741 m2/g. This indicates that, besides
the coalescence of micropore, new mesopore was also generated
during activation to account for the increase of the overall
mesopore surface area. Despite ZnCl2/SSH ratio, the samples
activated at 550 C shows slightly higher BET surface area than that
activated at 650 C. This may be due to more severe vaporization of
the activating agent at 650 C as ZnCl2 vaporizes in the temperature