η-Carbides (Co, Mo, or W) Nanoparticles from Octacyanometalates Precursors-Based Network

This paper describes a simple, two-steps chemical pathway to obtain bimetallic carbide nanoparticles (NPs) of general formula MxM″yC, also called η-carbides. This process allows for a control of the chemical composition of metals present in the carbides (M = Co and M″ = Mo or W). The first step involves the synthesis of a precursor consisting of a network of octacyanometalates. The second step consists in a thermal degradation of the previously obtained octacyanometalates networks under neutral atmosphere (Ar or N₂ ). It is shown that this process results in the formation of carbide NPs with diameter of ≈ 5nm, and the stoichiometries Co₃ M'₃ C, Co₆ M'₆ C, Co₂ M'₄ C for the CsCoM' systems.