Spatial Confinement of Electron-Rich Ni Nanoparticles for Efficient Ammonia Decomposition to Hydrogen Production

In this study, a CeO2 and BN hybrid-supported Ni catalyst (Ni/CeO2–BN) was developed for efficient NH3-to-H2 conversion. By adding BN to Ni/CeO2 as an additional support material, there is increased spatial distribution of Ni nanoparticles, lessening the common problem of Ni aggregation on oxide supports. More importantly, the introduction of BN enriches oxygen vacancies and raises Ce3+ concentration, leading to enhanced electron transfer from the support to Ni. The electron-rich Ni species promote NH3 activation as well as the combination of surface N atoms for N2 desorption, ultimately boosting NH3 decomposition. The 5 wt %Ni/CeO2–BN catalyst shows robust activity for NH3 conversion with a H2 yield of approximately 516 mmol gNi–1 min–1 at 600 °C. This study provides a universal strategy to boost the catalytic performance of metal/oxide catalysts by adding a second support material, which is a simple but effective way to produce efficient catalysts for a diversity of energy-conversion systems.