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 °C and 95% at 550 °C, maintaining excellent stability over 100 h at a high GHSV of 30 000 mL g⁻¹ h⁻¹, 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.