Melamine-induced molecular bridge facilitates the synthesis of highly strained ordered Pt₃Co catalysts for fuel cells

Pt₃Co catalysts represent promising substitutes for commercial Pt/C catalysts for proton exchange membrane fuel cells, yet their scalable deployment is restricted by inefficient synthesis, insufficient activity and stability. Herein, a functional molecular layer was in-situ constructed on platinum surfaces with the melamine assistance. Melamine acted as a molecular bridge to enrich Co on Pt via hydrogen-bonding interactions and facilitate PtCo charge transfer. Subsequent medium-low temperature heat treatment yielded a highly ordered Pt₃Co with strong compressive strain. The catalyst delivers a half-wave potential (E_1/2) of 0.928 V in acidic electrolyte. It exhibits merely 12 mV decay in E_1/2 and 1.5% loss of the electrochemical active surface area after durability test. At low Pt loading, it achieves high power densities of 2.94 W cm^-2 for H₂-O₂ fuel cells and 1.11 W cm^-2 for H₂-Air fuel cells, respectively. Compressive strain weakens the adsorption of intermediate and product H₂O and accelerates reaction kinetics. Meanwhile, the ordered intermetallic structure and robust PtCo interaction enhance structural stability. This strategy enables the mild and scalable fabrication of high performance ordered Pt₃Co catalysts.