Exploring hydrogen production over non-thermal ammonia electrolysis: A practical review

Hydrogen production through ammonia electrolysis presents a promising pathway for achieving clean and sustainable energy. Non-thermal ammonia electrolysis, in particular, has gained attention due to its potential to generate hydrogen at lower temperatures, offering several advantages over traditional thermal methods. This review critically examines the recent advancements in non-thermal ammonia electrolysis technologies, focusing on catalyst development, electrochemical performance, and reaction mechanisms. Various catalytic materials, including earth-abundant and noble metals, are evaluated for their efficiency and stability in ammonia oxidation reaction (AOR). The review also explores the role of electrolytes, reactor designs, and operating conditions that influence hydrogen yield and system efficiency. By analysing the current challenges and breakthroughs, this paper aims to highlight key research directions and the viability of non-thermal ammonia electrolysis as a scalable and efficient method for hydrogen production in the future. Ammonia decomposition for hydrogen production can be achieved through thermocatalytic, electrochemical, photocatalytic, or assisted methods (e.g., plasma, microwave), with applications in mobile platforms, and stationary systems such as industrial energy storage, and ammonia synthesis. Electrochemical approach offers a clean, efficient, and sustainable alternative to traditional hydrogen production methods, capitalising on ammonia's high hydrogen density. This include direct electrolysis of liquid ammonia, alkaline aqueous ammonia electro-oxidation, and acidic/neutral electrolyte-based electrolysis with anion/proton exchange membranes. • Non-thermal ammonia electrolysis for low-energy hydrogen production. • Advances in catalyst design for optimized electrolysis performance. • Addressing stability, scalability, and practical implementation. • Green benefits and cost analysis of non-thermal electrolysis.