This dissertation presents the development of advanced catalytic materials for pellistor-type gas sensors designed for the reliable detection of combustible gases. Conventional pellistors typically operate at high temperatures and suffer from limited long-term stability due to catalyst deactivation. To address these limitations, a novel material system based on mesoporous cobalt oxide (Co₃O₄) decorated with gold–palladium (Au–Pd) nanoparticles is introduced. By tailoring the material structure, surface properties, and deposition parameters, enhanced methane sensitivity is achieved at significantly reduced operating temperatures below 300 °C. The study demonstrates that the mesoporous structure enables increased catalyst loading and improved gas accessibility, while the interaction between Au–Pd and Co₃O₄ plays a crucial role in catalytic activity. In addition, the influence of layer thickness, catalyst composition, and operating conditions on sensor performance is systematically investigated. The results provide detailed insights into the relationship between material design, catalytic behavior, and long-term stability, highlighting the potential of Au–Pd@Co₃O₄ as a promising candidate for next-generation, energy-efficient catalytic gas sensors with improved resistance to catalyst poisoning.