Decreasing the O2‐to‐H2O2 Kinetic Energy Barrier on Dilute Binary Alloy Surfaces with Controlled Configurations of Isolated Active Atoms

Abstract Shifting from the typical 4e – pathway to H 2 O in electrochemical oxygen reduction to the 2e – pathway to H 2 O 2 is increasingly recognized as an environmentally friendly approach for producing H 2 O 2 . However, the competitive 4e − pathway is a significant obstacle to the production of H 2 O 2 since H 2 O is the thermodynamically favored product. Here, a series of Pt, Pd, and Rh active atoms diluted within inert‐Au matrices with precisely controlled atomic arrangements and coordination environments are synthesized via facet engineering for O 2 ‐to‐H 2 O 2 production. Surprisingly, individually dispersed Pt atoms within the Au surface enclosed by the square atomic arrangements exhibit superior H 2 O 2 selectivity and achieve a maximum selectivity of 90% at 0.36 V versus the reversible hydrogen electrode. Operando synchrotron ambient pressure X‐ray photoelectron spectroscopy identifies the presence of *OOH key intermediates on these isolated Pt active sites. Grand canonical density‐functional theory also reveals that the kinetic energy barrier for the 2e − pathway (0.08 eV; OOH* + H + + e − → H 2 O 2 ) on the isolated Pt sites is significantly lower than the 4e − pathway (0.29 eV; OOH* + H + + e − → O* + H 2 O). This work enables atomic‐scale control in dilute binary alloy surfaces with specific configurations of isolated active atoms and provides essential guidance for catalyst design to boost O 2 ‐to‐H 2 O 2 production.