(111f) Dynamic-Magnetic-Field-Enhanced Thermal Catalysis for Hydrogen Recovery from Ammonia Decomposition

In addressing the inherent challenges in hydrogen storage, transport and utilization, ammonia is regarded as an energy vector. Storing hydrogen in ammonia, followed by onboard generation of hydrogen through NH₃ decomposition, presents a promising solution. Within the framework of energy efficiency and mitigating carbon emissions, electrified processes such as plasma and microwave-assisted catalysis have been explored for hydrogen production from ammonia. Akin to these electrified processes, magnetic induction heating (MIH) has emerged as another promising alternative, offering a novel approach by integrating oscillating magnetic fields with existing standard thermal reactors. In this field-enhanced dynamic thermal catalysis, susceptor catalysts convert high-frequency oscillating electromagnetic fields to heat. This mode of heating allows for uniform direct heat generation in the catalyst bed, reaching the desired temperature in a shorter time and improving energy efficiency. More importantly, while MIH is traditionally viewed as an alternative heating method, its reliance on continuous unpaired electron spin alignment/dealignment suggests broader implications for catalysis— meaning MIH brings more than just heat but touches the core of how reactions happen. With Ru/Fe₃O₄, a ferromagnetic catalyst tailored for NH₃ decomposition due to its dynamically regulated Ru-N binding, exhibited superior catalytic performance in MIH mode with a nearly 50-fold increase in activity below 300 °C compared to standard thermal counterpart under similar reaction conditions and catalyst structures. When compared to benchmark Ru/Al₂O₃ catalysts, the MIH-triggered catalysis resulted in a nearly 7-fold increase in activity. These insights extend to other thermal reactions, such as CO oxidation and CO₂ reduction, where the contrast and benefits of MIH are observed. These findings position MIH as a new reaction category where the kinetics can be dramatically different from the standard thermal counterparts, offering a unique opportunity to dynamically modify the catalyst's spin states during the otherwise “static” thermal catalysis.