Decomposition of NH ₃ and Subsequent Combustion in an Integrated Ru-/Pt-Catalytic Microreactor

Ammonia is a promising carbon-free fuel, but its use is limited by high ignition temperature and NOx emissions. This work proposes an integrated microreactor using a sequential decomposition–combustion strategy for clean power generation from pure ammonia. Ru-coated microchannels first drive endothermic NH3 decomposition, producing an H2–N2 mixture that then burns in a central channel. Kinetic analysis shows Ru-catalyzed decomposition outperforms gas-phase reactions and exhibits nonmonotonic pressure dependence. A plug-flow reactor network confirms that coupling Ru-catalyzed decomposition with Pt-catalyzed combustion greatly improves NH3 conversion and N2 selectivity while suppressing NOx. A two-dimensional model further shows that Pt in the combustion channel enhances heat recirculation and markedly reduces NO emissions by lowering gas temperature and limiting thermal NOx formation. The integrated microreactor offers a compact, efficient route to ultralow-NOx ammonia-based power systems.