Behavior of Mixtures of Ammonia Complexes of Platinum(II) and Oxometalates in Aqueous Alkaline Solutions (Autoclave Conditions)

The results of studies on the preparation of highly dispersed bimetallic materials based on platinum with chromium, molybdenum, and tungsten under autoclave conditions at 190°C are summarized in this report. The thermodynamic and chemical features of the interactions between [Pt(NH₃)₄]Cl₂ and (NH₄)₂CrO₄, (NH₄)₂MoO₄ and (NH₄)₂WO₄ are considered. Solid products (powders) are represented by two phases—Pt and disordered solid solutions based on platinum. The morphology of powders has been studied—spherical particles with a diameter of 300–700 nm form agglomerates up to 2 µm. A route for the reduction of platinum (II) and oxometalate anions to the corresponding metals with intrasphere ammonia is proposed. The results of this work can form the basis for the synthesis of catalysts that are widely used in a number of industrially important reactions.