Structural Identification and Enhanced Catalytic Performance of Alumina-Supported Well-Defined Rh-SnO₂ Close-Contact Heteroaggragate Nanostructures

This work illustrates direct evidence of the formation of close-contact Rh-SnO₂ heteroaggregate interfaces, and their enhanced catalytic hydrogenation performance is also demonstrated. Alumina-supported Rh-SnO₂ heteroaggregate nanocatalysts were prepared by in situ transformation of Rh@Sn core–shell nanostructures. Various characterization techniques, especially the studies of high angle annular dark field scanning transition electron microscopy with phase mappings, confirm that Rh-SnO₂ close-contact heteroaggragate nanostructures were obtained by in situ calcination and following reduction of Rh@Sn core–shell nanoparticle precursors. The catalytic studies for hydrogenations of various substituted nitroaromatics show that the Rh-SnO₂/Al₂O₃ heteroaggregate nanocatalysts not only improve the catalytic conversions but also enhance the catalytic selectivity. The combination of characterization and catalytic studies suggests that a synergistic effect originated from close-contact Rh-SnO₂ heteroaggregate interfaces exists in the Rh-SnO₂ system, which enhances their catalytic hydrogenation performance.