Facile synthesis based on novel carbon-supported cyanogel of structurally ordered Pd₃Fe/C as electrocatalyst for formic acid oxidation

A novel carbon-supported cyanogel (C@cyanogel)-derived strategy is used to synthesize an intermetallic Pd₃Fe/C compound of the desired ordered Pd₃Fe phase with a small particle size. The novelty of this work lies in using carbon-supported K₂Pd^IICl₄/K₄Fe^II(CN)₆ cyanogel as a reaction precursor, generated through the substitution of two chloride ligands by the nitrogen ends of the cyanide ligands on the metal center. The inherent nature of cyanogels can effectively suppress the movement of Pd⁰ and Fe⁰ nuclei in the crystal, benefiting the formation of the intermetallic, which is otherwise challenging via traditional synthesis techniques. The ordered Pd₃Fe/C catalyst exhibits excellent catalytic activity and good cycle stability for the formic acid oxidation (FAO) reaction relative to the properties of disordered Pd₃Fe/C and commercial Pd/C catalysts, demonstrating that the ordered Pd₃Fe/C is a promising replacement for commercial Pd-based catalysts. The outstanding performance can be ascribed to the full isolation of active sites in the ordered Pd₃Fe structure and the modified electronic structure of the active components. This work provides an effective and novel route to obtain Pd-based intermetallic compounds with potential applications in a wide range of electrocatalysis.