Solid-state thermal transformations in mixtures of platinum(II) tetraammine with ammonium chromate and ammonium dichromate

Resumo

Thermal transformations of 3[Pt(NH₃)₄]Cl₂–(NH₄)₂CrO₄ (I) and 3[Pt(NH₃)₄]Cl₂–2(NH₄)₂Cr₂O₇ (II) mixtures in a solid state have been studied by thermal analysis and mass spectrometry in an inert (Ar) atmosphere and air at temperatures from 40 to 550°C. The chemical and phase compositions of the thermolysis products obtained in argon have been determined: Pt and Cr₂O₃ in mixture I and Pt, a platinum-based Pt_{1 – y}Cr_y solid solution, and Cr₂O₃ in mixture II. The thermal transformation products of mixtures I and II in air consist of two phases: Pt and Cr₂O₃. It has been shown that interactions in the mixtures proceed through the formation of a metallic chromium phase. The materials obtained in this study can find application as catalysts for low-temperature fuel cells, as well as for organic synthesis processes.