In situ bubble template-assisted synthesis of phosphonate-functionalized Rh nanodendrites and their catalytic application

The controllable synthesis of branched noble metal nanostructures has attracted significant attention as it provides excellent catalytic activity and durability to these metal nanostructures. In the present study, a facile and effective complexation-reduction strategy was developed for synthesizing Rh nanodendrites with hippocampus tail-like branches (Rh-NDHTs) using N₂H₄·H₂O as a reductant and multiphosphonate molecule with small molecular weight as a complexant and functional agent. During the synthesis, the coordination interaction between multiphosphonate and RhCl₃ as well as the hydrazine decomposition reaction (H₂NNH₂ = N₂ + 2H₂) catalyzed by the freshly formed Rh nanocrystals play important roles in the generation of Rh-NDHTs. Moreover, phosphonate functionalization of Rh-NDHTs was simultaneously achieved during the course of the synthesis, originating from the strong adsorption of multiphosphonate on the Rh surface. When used as a heterogeneous catalyst for the o-phenylenediamine oxidation reaction, the phosphonate-functionalized Rh-NDHTs exhibited enhanced catalytic efficiency and durability as compared to the commercially available Rh nanocrystals, attributing to their extraordinary morphological and interfacial properties.