Autothermal recirculating reactor (ARR) with Cu-BN composite as a stable reactor material for sustainable hydrogen release from ammonia

Ammonia (NH 3 ) has been proposed as a viable hydrogen (H 2 ) carrier, but high reaction temperature and endothermic nature of NH 3 decomposition require an efficient reaction system to maximize useable energy from NH 3 . Adoption of carbon-free heat sources and efficient heat transfer to the reaction bed are crucial for sustainable H 2 release. Herein, the autothermal recirculating reactor (ARR) concept with the fractional utilization of the reformate H 2 as a clean combustion fuel is proposed and experimentally investigated. Additionally, BN-coated Cu as a composite reactor material is developed for heat transfer enhancement of high-temperature H 2 release reaction in a thermally-coupled NH 3 decomposition and H 2 combustion system. Coating performance against chemical degradation of Cu has been tested and confirmed. High NH 3 conversion of >99.6% and reforming efficiency of 70.95%, even with high fraction of heat loss owing to small scale validation, show feasibility of the as-proposed reformer. Operation of the suggested system is envisaged with self-sustained heat supply for production of 84 W of electrical power. Also, the as-proposed reactor concept and material are suggested to serve in other endothermic H 2 release reactions from various H 2 carriers (methane, methanol, LOHC, etc) for potential application in power generation as well as high-purity H 2 production. • Combustion of reformate H 2 was used as a heat source for NH 3 decomposition. • Reforming efficiency of 70.95% was achieved with a lab-scale autothermal reformer. • Fuel cell equivalent power of 84 W was obtained with CO X -free operation. • Cu-BN was proposed as a viable reactor material for temperature-sensitive reactions. • Autothermal NH 3 decomposition can be envisaged for onboard power generation.