Molecular Solar Thermal (MOST) systems aim to store solar energy as chemical energy, with controlled and efficient heat release on demand being a critical, yet less explored, aspect. While photochemical, electrochemical, and thermal inputs have been suggested, heterogeneous catalysis offers practical advantages for heat release applications, making it the most viable option for real devices. Recent advances include the development of a robust protocol for evaluating heterogeneous catalysts for the back-conversion, optimized for practical conditions and minimal catalyst use. This protocol revealed that oxidized catalysts (e.g., Pt-Ox, Cu-Ox) exhibit significantly superior performance compared to their reduced counterparts. Furthermore, the transition to flow systems, like packed-bed reactors, is crucial for large-scale application. Studies in flow conditions have highlighted that catalyst particle size and flow rate are key factors influencing conversion and heat release, with smaller particle sizes and higher flow velocities improving reaction homogeneity and minimizing mass transport limitations. The ultimate objective is to develop robust, efficient, and economically accessible catalysts for this promising energy technology.