A novel nanocomposite catalyst for thermal degradation of the ammonium perchlorate (AP) has been synthesized, and its effect on the thermal behavior of AP has been investigated. Preparation of the catalyst was carried out via functionalization of the graphene oxide with phenyl isocyanate and its noncovalent bonding to catocene. The catalytic activity of the catalyst was studied by thermal gravimetric analysis/differential scanning calorimetry at various heating rates. In addition, the effect of the catalyst on the AP thermal decomposition has been investigated by Kissinger and Friedman methods as two model‐free methods for calculation of the activation energy parameter. According to the Kissinger method calculations, the Ea of AP decomposition reduced about 151 kJ⋅mol−1 lower than the reported value for pure AP in the presence of the catalyst. Calculation of the Ea value for various reaction conversion rates by the Friedman method also confirmed the Kissinger method results.