From thermal catalysis to external-field-assisted ammonia decomposition.

Ammonia decomposition is increasingly viewed as a key technology for on-demand hydrogen production, yet its development is often discussed separately across thermal catalysis, plasma-assisted, photocatalytic, and photothermal research communities. Here, we argue that the central challenge is not solely catalyst optimization, but the effective coupling of energy delivery and catalytic reaction pathways. By examining ammonia decomposition through an energy-driven framework, we compare how heat, electrons, photons, and their combinations influence reaction kinetics, activation mechanisms, and energy efficiency. We further discuss whether emerging non-equilibrium approaches can relax the intrinsic kinetic limitations associated with adsorption-energy scaling relationships in thermal catalysis. This review provides a unified view of ammonia decomposition technologies and outlines future directions toward low-temperature and energy-efficient hydrogen generation.