Boosting ammonia decomposition for hydrogen production over Co/CeO2 catalysts via Sr doping

Abstract

The development of efficient and cost-effective catalysts is crucial for ammonia decomposition to establish a carbon-free hydrogen energy system. In this work, we developed a non-noble metal Sr-doped Co/CeO2 catalyst synthesized via a sol-gel method, demonstrating outstanding catalytic performance and stability. It achieved NH3 conversions of approximately 76% at 500 ℃ and 95% at 550 ℃, maintaining excellent stability over 100 h at a high GHSV of 30000 ml/g·h, which is markedly superior to the undoped Co/CeO2. Comprehensive characterization reveals that enhanced performance originates from a synergistic promotion mechanism initiated by Sr doping. The dynamic redistribution of incorporated Sr species under reaction conditions is pivotal for maximizing their electron-donating capability. This process concurrently drives the creation of abundant oxygen vacancies and strengthens the metal-support interaction, thereby stabilizing the active cobalt species. These interconnected modifications collectively optimize the electronic structure of the catalyst. The optimized electronic configuration facilitates N-H bond activation while weakening the adsorption of reaction products, ultimately accelerating the overall catalytic cycle. This work underscores that engineering the electronic structure of catalyst supports through aliovalent doping is a highly effective strategy for designing advanced ammonia decomposition catalysts.