• • Active-site tuning remains central: noble-metal catalysts require optimized NHx adsorption/dehydrogenation and poisoning suppression; Ni-based catalysts demand regulation of NiOOH-like reconstructed phases to balance activity and selectivity.
• • Interfacial engineering controls selectivity and stability: heterointerfaces, defects, and doped coordination environments alter AOR vs. OER competition and product branching toward N2 or oxygenated species.
• • Device-oriented development is essential: practical DAFCs, ammonia electrolyzers, and SOFCs are limited by membrane compatibility, mass transport, ammonia crossover, thermal management, and durability, not just intrinsic activity.
• • Future progress requires coordinated optimization from active materials to electrode architectures and full-device systems to bridge lab-scale catalysts and industrial ammonia energy technologies.