Self-powered sensing systems that can work without external power sources have recently been demonstrated to detect pH, humidity, pressure, and temperature. By harvesting energy directly from the environment, these self-powered sensing systems are advantageous in minimizing the size, having long-term operation, and avoiding the use of toxic materials in battery. In this paper, we prepared Au/Pd nanomaterials as the nanocatalysts in the self-powered sensing systems. Au nanoparticles were synthesized first and served as the seeds for the growth of Pd component. The content of Pd component on the Au nanoparticles could be varied by reacting with different concentration of Pd²⁺ ions. Cyclic voltammetry indicated that the electrocatalytic oxidation of ethanol was dependent on the content of Pd component. Finally, we combined the as-prepared Au/Pd nanomaterials with a self-powered sensing system for ethanol detection. The self-powered ethanol sensor developed here could become a real sensing system in the futures.