Ammonia (NH3) is a promising intermediate for hydrogen (H2) storage and transport with the capability of being decomposed back to H2 on-site for practical applications. Given the endothermic nature of NH3 decomposition, it is highly desirable to operate NH3 cracking without relying on a continuous external energy supply, while highly selectively separating H2 in situ to boost NH3 conversion and produce high purity H2 to meet fuel-cell operation requirements. In this work, a self-sustained, modular catalytic membrane reactor (CMR) was designed and fabricated for NH3 decomposition and H2 purification by the integration of Ru-based catalyst, palladium/silver membrane, and an H2 catalytic oxidation burner in a single unit. High purity H2 recovered in the permeate stream, while H2 in the retentate stream was mixed with air and fed back to the integrated H2 burner in the reactor for combustion, providing the required energy for NH3 decomposition. Self-sustained NH3 decomposition was successfully demonstrated by applying different NH3 flowrates and operating conditions to maximize the recovered H2. The CMR was then operated using 2.6 liter per minute (LPM) NH3 for more than 100 h, excluding reactor initiation and shutdown times, and showed >99% NH3 conversion and ~52% of H2 recovery with an overall H2 production rate of ~0.25 kg/day. The produced H2 contained less than 0.01 ppm NH3, meeting the operation requirements for fuel cells. Steady state operation revealed negligible NOX concentrations in the burner exhaust. This contribution may pave the way for advanced H2 production technologies that support the growing demand for clean and reliable energy solutions.
