Surface structural evolution during the thermal decomposition of a PdO(101) thin film

► High-quality PdO(101) film grown at 500 K. ► PdO(101) thin film undergoes autocatalytic decomposition. ► STM reveals that reduced sites catalyze PdO decomposition. ► Kinetic anisotropies produce chains and loops of reduced sites. ► Reduced surface domains are also re-oxidized by underlying oxide.