Chemical compositions for emergency oxygen generators typically include sodium chlorate (NaClO3) as the oxygen source, transition metal oxide as catalyst for NaClO3 decomposition, and metal fuel to provide energy for self-sustained combustion. To clarify the role of metal fuel in the combustion mechanism, potential catalytic effects of metals on NaClO3 decomposition are investigated. Thermal analysis was conducted in argon flow for binary NaClO3/Me mixtures, where Me = Al, Fe, Co, Ni, and Sn, as well as in oxygen flow for metal powders alone and mixtures of NaClO3 with Sn and Co. The experiments show that catalytic effects of metals on NaClO3 decomposition range from negligible for Al and Sn, to significant for Co and Ni, while Fe exhibits moderate catalytic activity. Thermodynamic calculations indicate that replacement of Sn with Co or Ni does not significantly alter combustion characteristics, which determine product oxygen flow rate. Replacing Sn with Co or Ni may decrease the number of ingredients in oxygen generators, since these metals both catalyze and fuel the process.