One-Step Synthesis of a High Performance Pt-Fe₃O₄ Catalyst: Intermetallic Al₁₃Fe₄ as a Platform and Precursor

Abstract: A one-step process was developed to prepare catalysts with monodispersed Pt nanocrystals on Fe₃O₄, based on leaching of the intermetallic compounds Al_76.5−xFe_23.5Pt_x (at%: x = 0, 0.05, 0.5, 1) with an aqueous 10 wt% NaOH solution. In this process, the intermetallic Al₁₃Fe₄ lattice acts as a platform in which Pt atoms can be homogeneously dispersed, and also serves as a precursor for subsequent leaching. Compared with conventional preparation methods, including impregnation and coprecipitation, this one-step process eliminates the need for thermal treatments such as high temperature calcination and/or reduction, thus minimizing the sintering or crystal grain growth problems caused by these treatments. Consequently, the materials derived from Al₇₆Fe_23.5Pt_0.5 exhibit high catalytic performance during CO oxidation and the CO-PROX reaction due to the monodispersed Pt nanocrystals in the porous or nanoparticle Fe₃O₄ matrix. Graphical Abstract: A high performance nanocomposite Pt-Fe₃O₄ catalyst, consisting of monodispersed Pt nanocrystals in a porous Fe₃O₄ matrix, was prepared by a one-step process based on caustic leaching of a bulk Al₁₃(Fe + Pt)₄ intermetallic compound.[Figure not available: see fulltext.]