Study on the support effect and structure–activity relationship of cobalt-based hydrogen production catalysts by ammonia reforming

Abstract

To break through the bottleneck in hydrogen storage and transportation and advance the industrial application of the "ammonia-hydrogen" energy route, this study focuses on the support effect of cobalt-based non-precious metal ammonia decomposition catalysts. Through the deposition–precipitation method, cobalt-based catalysts loaded on different oxide supports (CeO₂, La₂O₃, SiO₂, etc.) were prepared. Combined with XRD, TEM, XPS, and other methods for characterization, the effect of the physical and chemical properties of the supports on the structure and ammonia decomposition performance of the catalysts was systematically explored, and kinetic analysis and stability tests were carried out. The activity test shows that the chemical effect of the support has a much greater impact on the catalytic efficiency than the physical specific surface area. Nano-sized oxide supports deliver far better catalytic performance than their microsized counterparts, which we attribute to the richer surface structural defects and oxygen vacancies on nano-support; these defects strengthen metal–support interaction and optimize the electronic state of cobalt active sites. The cobalt-based catalyst loaded on CeO₂(N) (Co/CeO₂(N)) performed the best, with an ammonia conversion rate of 46.3% at 450 ℃ and approaching complete decomposition (94.2%) at 550 ℃, significantly superior to traditional Al₂O₃ and TiO₂ support catalysts. This research clarifies the correlation between support properties and the structure–activity relationship of cobalt-based catalysts, and confirms that CeO₂(N) can enhance catalytic performance through electronic regulation and the synergistic effect of basic sites, providing a theoretical foundation and technical support for the design and development of low-cost, high-stability ammonia decomposition catalysts.