Recent Advances in Bimetallic Catalysts for Hydrogen Production from Ammonia

Abstract

The emerging concept of the hydrogen economy is facing challenges associated with hydrogen storage and transport. The utilization of ammonia as an energy (hydrogen) carrier for the on‐site generation of hydrogen via ammonia decomposition has gained attraction among the scientific community. Ruthenium‐based catalysts are highly active but their high cost and less abundance are limitations for scale‐up application. Therefore, combining ruthenium with cheaper transition metals such as nickel, cobalt, iron, molybdenum, etc., to generate metal‐metal (bimetallic) surfaces suitable for ammonia decomposition has been investigated in recent years. Herein, the recent trends in developing bimetallic catalyst systems, the role of metal type, support materials, promoter, synthesis techniques, and the investigations of the reaction kinetics and mechanism for ammonia decomposition have been reviewed.

Ammonia as a Carbon-Free Energy Carrier: NH3 Cracking to H2

“…Chen and others (2021) focused on Ru-based catalysts, while Bell and Torrente-Murciano (2016) reported the ammonia decomposition using non-noble metal catalysts . Bimetallic catalysts for hydrogen production from ammonia have been investigated by Khan and others (2022) …”

“…25 Bimetallic catalysts for hydrogen production from ammonia have been investigated by Khan and others (2022). 26 The reaction mechanism for ammonia cracking is detailed in the following, where the asterisk symbol (*) stands for the catalyst active site.…”

Promotion of Low-Temperature Catalytic Activity of Ru-Based Catalysts for Ammonia Decomposition via Lanthanum and Cesium Codoping

“…6−8 Therefore, ammonia is now considered as a promising and efficient hydrogen carrier. 9−11 Ammonia decomposition is an endothermic process, 12 which means high temperature is usually required to achieve a full conversion. To date, the development of ammonia decomposition catalysts with good low temperature activity remains a big challenge and becomes a hot topic over the past decades.…”

Research Status, Optimization Strategies, and Future Prospects of Ammonia Decomposition Catalysts for COx-Free Hydrogen

“…Bimetallic catalysts, such as Co–Mo, Mg–Fe bimetallic catalysts, often show better activity than monometallic catalysts due to synergistic effects of bimetals, with the exception of Ru-based bimetallic catalysts . With the development of controlled bimetallic synthesis technology, bimetallic catalysts are also emerging as competitive candidates for ammonia decomposition catalysts.…”

“…17 based bimetallic catalysts. 27 With the development of controlled bimetallic synthesis technology, bimetallic catalysts are also emerging as competitive candidates for ammonia decomposition catalysts. Metal amides and imides are new catalysts with excellent activity recently proposed, 28 and they have great potential to become efficient ammonia decomposition catalysts for hydrogen production.…”