Temperature modulation for enhanced catalytic NH3 decomposition

On-site hydrogen (H 2 ) production is crucial for supporting the growing energy infrastructure while reducing our carbon footprint. Ammonia (NH 3 ) cracking is a prevalent reaction for on-demand H 2 production, with ruthenium (Ru) exhibiting the highest activity among single metal catalysts at low temperatures. Current efforts are focused on catalyst development to enhance activity at low reaction temperatures. In this work, we introduce programmable temperature modulation as an alternative. We achieve the highest reported H₂ production rate compared to conventional Ru-supported processes at relatively low average temperature and power. Dynamic heating shows superior performance compared to steady state heating. We investigate the effects of sintering, particle size, and hydrogen inhibition on NH 3 cracking under both heating modes. Introducing dynamic microkinetic modeling with site populations from machine-learned force field molecular dynamics simulations we demonstrate that transient high-temperature exposure promotes surface species desorption, improving catalytic activity. • Highest H₂ production rates among conventional Ru-supported catalysts at 415 °C. • Rapid temperature pulsing mitigates H₂ inhibition. • Transient high-temperature exposure promotes desorption of NH₂* from step sites. • Thermally-induced, reversible, nanosecond-scale catalyst restructuring.