The increasing demand for ethylene and propylene has stimulated extensive research on propane dehydrogenation (PDH) for short-chain olefin production. However, catalyst deactivation and limited real-time monitoring remain key challenges in microwave-assisted PDH systems. In this study, we investigated waste-derived Pt-based bimetallic catalysts (Pt–Fe and Pt–Cu) and evaluated the feasibility of integrating real-time hydrogen sensing for in situ process monitoring. Waste Pt catalysts were recycled and modified with Fe and Cu, and combined with microwave-absorbing microparticles to enhance energy utilization and catalytic performance. Reactions were conducted at 450 W for 360 min with a propane feed rate of 10 mL/min. Hydrogen concentration was continuously monitored using a Siemens Calomat 62 sensor installed in the tail gas line, enabling the real-time evaluation of catalyst activity and deactivation behavior. This work presents a novel strategy by integrating sustainable Pt catalyst recycling with in situ hydrogen sensing for microwave-assisted PDH monitoring. The Pt–Fe catalyst produced 7.5% ethylene and 3.0% propylene with 69.4% hydrogen, whereas Pt–Cu exhibited superior performance with 9.5% ethylene, 11.9% propylene, and 78.8% hydrogen. SEM analysis revealed distinct coke morphologies associated with catalyst deactivation. The results demonstrate that combining bimetallic catalyst modification with hydrogen sensing significantly improves process monitoring and performance evaluation in microwave-assisted PDH systems. Further studies on long-term stability and scale-up are required for industrial application.