  In this work, we revisited the Ziff-Gulari-Barshad (ZGB) model to study its
phase transitions and critical exponents through time-dependent Monte Carlo
simulations. We used a method proposed recently to locate the non-equilibrium
second-order phase transitions and that has been successfully used in systems
with defined Hamiltonians and with absorbing states. This method, which is
based on optimization of the coefficient of determination of the order
parameter, was able to characterize the second-order phase transition of the
model, as well as its upper spinodal point, a pseudo-critical point located
near the first-order transition. The static critical exponents $\beta $,
$\nu_{\parallel }$, and $\nu_{\perp }$, as well as the dynamic critical
exponents $\theta $ and $z$ for the second-order point were also estimated and
are in excellent agreement with results found in literature.
