  It has been known that the catalytic effect makes the life-time of a
metastable state shorter. We discuss this phenomenon in a decay process of a
metastable vacuum in the brane-limit of type IIB string theory. Due to the
non-linear effect of DBI action, the bubble created by the decay makes an
energetically favorable bound state with an impurity that plays the role of
catalyst, which is quite specific to this model and different from other
catalysts such as a back hole. Furthermore, we found that this low-energy
effective theory around almost unstable regions reduces to a simple quantum
mechanical system, and the vacuum life-time can be calculated using known
results, even beyond the WKB approximation. Finally, we compare the life-time
of the vacuum with the Trans-Planckian Censorship Conjecture (TCC) and find
that as long as the string scale is at least one order magnitude smaller than
the Planck scale, there is a nonzero window to satisfy the TCC condition.
