Morphology-dependent oxygen vacancies and synergistic effects of Ni/CeO2 catalysts for N2O decomposition

Abstract

Oxygen vacancies and metal–support synergistic effects in heterogeneous catalysis play a decisive role in catalytic efficiency. In this work, NiO supported on ceria nanorods (Ni/CeO₂-NR) and ceria nanocubes (Ni/CeO₂-NC) catalysts exhibit strong morphology-dependent oxygen vacancies content and NiO–CeO₂ synergistic actions for N₂O decomposition. Ni/CeO₂-NR catalysts possess higher amounts of oxygen vacancies than Ni/CeO₂-NC, while Ni/CeO₂-NC samples display stronger metal–support synergistic actions to anchor more surface NiO clusters and boundary Ni–O–Ce nanostructures. Catalytic activity tests show that Ni/CeO₂-NC catalysts exhibit a superior efficiency to Ni/CeO₂-NR catalysts. The outstanding catalytic activities of Ni/CeO₂-NC catalysts are related to a larger number of surface NiO clusters and boundary Ni–O–Ce nanostructures, which are much more active than oxygen vacancies for N₂O decomposition. Furthermore, the boundary Ni–O–Ce is found to be a more reactive site than surface NiO clusters. This study presents a new strategy to design high-efficiency supported metal catalysts through controlling oxygen vacancies and metal–support synergistic effects by morphology-dependent synthesis.