  We present a theoretical investigation on the enhancement of the spin
coherence with periodic, concatenated, or Uhrig dynamical decoupling $N$-pulse
sequences in a $^{87}$Rb spin-1 Bose condensate, where the intrinsic dynamical
instability in such a ferromagnetically interacting condensate causes spin
decoherence and eventually leads to a multiple spatial-domain structure or a
spin texture. Our results show that all the three sequences successfully
enhance the spin coherence by pushing the wave vector of the most unstable mode
in the condensate to a larger value. Among the three sequences with the same
number of pulses, the concatenated one shows the best performance in preserving
the spin coherence. Interestingly, we find that all the three sequences exactly
follow the same enhancement law, $k_- T^{1/2} = c$, with $k_-$ the wave vector
of the most unstable mode, $T$ the sequence period, and $c$ a
sequence-dependent constant. Such a law between $k_-$ and $T$ is also derived
analytically for an attractive scalar Bose condensate subjecting to a periodic
dynamical decoupling sequence.
