Inhibition mechanism of aluminum hypophosphite inhibits aluminum dust explosions: Experimental and Reactive force field molecular dynamics simulations study

Aluminum (Al) is an attractive material for hydrogen generation through its reaction with water. This study assesses the effectiveness of aluminum hypophosphite (AHP) in inhibiting Al dust explosions and elucidates its decomposition pathway and inhibition mechanism. At a concentration of 1050 g/m 3 , AHP completely inhibited the maximum explosion intensity of Al dust. Its high activation energy and P–O cross-linking layer impeded heat transfer. Reactive force field molecular dynamics (ReaxFF-MD) simulations complemented that AHP decomposes into vital products such as PH 2 and H 2 PO 2 . Concurrently, CHEMKIN numerical calculations highlighted the crucial role of phosphorus hydroxide (PH) radicals in the recycling and regeneration of phosphorus radicals. The reaction PO 2  + PH⇔ HOPO + P accelerated the cycling of HOPO, thereby reducing the required radicals for sustaining aluminum combustion. AHP exhibits dual-phase inhibition against Al dust explosions, thereby guaranteeing the safe operation of aluminum-based hydrogen generation systems in the hydrogen energy domain.