Effect of dopamine modification on the oxygen reduction reaction activity of Pt/C catalyst

Modifying Pt-based catalysts with organic molecules offers a promising strategy to enhance oxygen reduction reaction (ORR) performance. In this study, dopamine (DA) was used to modify Pt/C, and its impact on electrochemical behavior and ORR activity was systematically investigated. Through DA modification, the ORR activity can be improved to 1.5 times that of pristine Pt/C. This enhancement is linked to DA's ability to maintain a more metallic Pt surface by preventing excessive oxidation. Density functional theory (DFT) calculations indicate that DA binds moderately strongly to the Pt surface, based on π-bonds between Pt and the aromatic carbons in a flat configuration that partially covers the surface while leaving active sites accessible. DA effectively inhibits the formation of surface-blocking OH top –OH bridge pairs on (111) terraces, thus preserving O 2 adsorption sites at (110) edges and unpaired OH top sites, which are necessary in the ORR. Thus, this work provides mechanistic insight into DA's function and suggests a practical route to improving fuel cell performance through organic–inorganic interface engineering. • DA-modified Pt/C boosts ORR activity up to 1.5 times over pristine Pt/C. • DA helps maintain metallic Pt by preventing excessive oxidation. • DA destabilize OH adsorption, preserving active sites for O 2 adsorption.