Facile Strategy To Prepare Rh Nanosheet-Supported PtRh Nanoparticles with Synergistically Enhanced Catalysis in Oxidation

Here, we report the one-pot synthesis of metal-based zero-dimensional (0D)/two-dimensional (2D) nanocomposites via a modified seed-mediated growth method. In this strategy, two metal precursors (H2PtCl6·6H2O and Rh(acac)3) were mixed together with HCHO as a reductant, followed by a solvothermal treatment, producing homogeneous PtRh bimetallic nanoparticles (NPs) supported on ultrathin Rh nanosheets (NSs) with trapezoidal shape and crystalline/amorphous hetero-phase characteristics. Intriguingly, successive processes including generation of PtRh NPs, formation of Rh NSs, and immobilization of PtRh NPs on Rh NSs were involved in the synthesis, creating a novel 0D/2D PtRh/Rh nanostructure. Several experimental parameters (reductant, precursor, surfactant, solvent, and temperature) were crucial to the formation of a unique structure, during which the preferentially formed Pt atoms/clusters as seeds not only accelerated the reduction of Rh precursors to form PtRh NPs but directed the formation of Rh NSs around PtRh NPs. Owing to both structural and electronic effects, PtRh/Rh exhibited synergistically enhanced activity in the aerobic oxidation. Mechanistic study further revealed that the reaction obeyed the Michaelis–Menten theory and PtRh/Rh-catalysis originated from both generation of important reactive oxygen species and rapid electron transfer. The results provide a facile yet effective avenue to fabricate a new type of Pt-based heterogeneous catalysts.