A Composition‐Precise Synthesis of Porous PtCo Alloy Catalysts Mediated by Aerosol‐Microdroplet Confinement

This work reports a composition‐precise synthesis of porous PtCo‐alloy catalysts mediated by aerosol‐microdroplet confinement, which begins with the complete conversion of inorganic salts into Pt‐Co‐PVP composite precursor, followed by calcination and reduction to yield a carbon‐supported PtCo alloy. A series of composition‐controlled PtCo/C alloy catalysts is synthesized. In situ XRD analysis provided clear evidence of the structural transformation from the Pt‐Co‐PVP composite to the PtCo alloy during calcination under a H 2 /Ar atmosphere. The process began at 300 °C with the concurrent formation of two distinct populations of alloy nanoparticles with high and low Pt/Co ratios. With increasing temperature, the high‐ratio nanoparticles are gradually converted into those with a lower ratio. The Pt/Co ratios in these catalysts demonstrated a remarkable consistency with the predetermined ratios in the mother solution. The Co/Pt mass ratio can span a wide range from 0 to 150%. As for a case application for electrocatalytic methanol oxidation reaction, the optimized Pt 1 Co 0.8 /C alloy catalyst achieved a mass activity of 1.8 A/mg(Pt), which is 2.4 times that of a commercial PtCo/C‐TKK catalyst, 2.2 and 4.4 times that of Pt 1 Co 0.8 /C‐Im and Pt/C‐Im catalysts prepared via impregnation. The aerosol‐microdroplet confinement strategy also enables the composition‐precise synthesis of other alloy catalysts.