Reprogramming Ammonia Oxidation Through Elementary Reaction Engineering

Ammonia oxidation electrocatalysis is emerging as a key enabling technology for sustainable ammonia utilization, spanning direct ammonia fuel cells, energy-efficient hydrogen production, and nitrogen-cycle management. However, the rational development of high-performance ammonia oxidation reaction (AOR) catalysts remains challenging because catalytic outcomes are determined by the coupled regulation of multiple elementary processes, including NH3 activation, NHx dehydrogenation, N–N coupling, and dynamic evolution of catalytic interfaces. Although substantial progress has been achieved in catalyst discovery and mechanistic characterization, current catalyst design remains predominantly guided by material composition and structural optimization, lacking a predictive framework that links reaction pathways with catalytic architectures. This Review establishes an elementary-reaction-centered design paradigm for AOR electrocatalysis, providing a mechanistic bridge between fundamental reaction chemistry and catalyst engineering. By integrating molecular catalytic cycles, operando identification of reactive intermediates, and emerging kinetic descriptors, the Review examines how catalytic structures regulate individual elementary transformations and reshape complex reaction networks. Within this framework, recent advances in the rational engineering of active sites, electronic structures, catalytic microenvironments, dynamic active phases, and device-level architectures are discussed as interconnected strategies for controlling AOR kinetics and selectivity. Rather than providing another material- or catalyst-class-based compilation of recent advances, this Review adopts the elementary reaction as the primary analytical unit and interprets catalyst structures according to the specific transformations and pathway competitions they regulate. By connecting molecular reaction sequences, operando-identified intermediates, kinetic descriptors, and catalyst architectures, the framework establishes a continuous mechanistic link from elementary-step regulation to reaction-network engineering. This perspective shifts AOR catalyst development from isolated activity optimization toward coordinated control of reaction pathways, providing a transferable conceptual basis for the rational design of complex multistep electrocatalytic systems.