Rhodium Encapsulated within Silicalite-1 Zeolite as Highly Efficient Catalyst for Nitrous Oxide Decomposition: From Single Atoms to Nanoclusters and Nanoparticles

Graphical A prominently size-dependent intrinsic catalytic activity or structure-sensitive catalysis in N 2 O decomposition appeared over Rh encapsulated within silicalite-1 (Rh@S-1). The size of metal species plays a pivotal role in governing catalytic performance of supported metal catalysts. In this work, a series of Rh encapsulated within silicalite-1 catalysts with different sizes were prepared by one-pot hydrothermal method and employed to catalyze the decomposition of N 2 O. Detailed structure determinations by HAADF-STEM, XPS and CO-DRIFTS demonstrate that subtle modulation of the encapsulated Rh species were achieved easily from single-atom to nanoclusters and nanoparticles by controlling the loading and reduction conditions of Rh. The turnover frequency (TOF) of N 2 O decomposition showed a typical volcano-type dependence on Rh size. Kinetic studies revealed that this structure-sensitive catalysis was related to the difference in N 2 O and O 2 adsorption/desorption for various Rh species. Furthermore, a Rh@S-1 catalyst with a proper Rh size (ca. 1.6 nm) was identified as the best-performing catalyst with a maximum TOF (ca. 95 h −1 ), showing much superior activity than other reported Rh-based catalysts.