Nanostructured PtZn intermetallic compound: Controlled formation from PtZn(CH3COO)4 molecular precursor and tests of catalytic properties
Phase transformations of a newly synthesized heterobimetallic ZnPt(OOCMe)4(H2O)(MeCOOH)2 acetate in a chemically reductive atmosphere at mildly elevated temperatures are thoroughly studied in order to optimize conditions for the formation of nanostructured PtZn intermetallic compound. According to XAFS and XRD data, the first stage of reductive thermolysis is the reduction of the noble metal, while zinc remains in an oxygen environment. At the second stage the reduction of Zn and the formation of the bimetallic solid solution with the fcc lattice occur. It is shown that recrystallization of solid solution to ordered PtZn intermetallic compound with the tetragonal structure occurs in a narrow temperature range of 250–275 °C. Based on these results, the optimum reduction temperature for the preparation of supported bimetallic Pt–Zn/Al2O3 catalyst was determined to be 300 °C. Results of catalytic tests of the supported material are reported.