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 (E1/2) of 0.928 V in acidic electrolyte. It exhibits merely 12 mV decay in E1/2 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.