Gaining insight into the impact of electronic property and interface electrostatic field on ORR kinetics in alloy...

Alloy engineering has been utilized as a potent strategy to modulate the oxygen reduction reaction （ORR） activity. However, the regulatory mechanism underpinning the ORR kinetics by means of alloy engineering is still shrouded in ambiguity. This work places emphasis on the kinetics of the ORR concerning Pt₃M (M = Cr, Co, Cu, Pd, Sn, and Ir) catalysts, and integrates theoretical prognostication and experimental validation to illuminate the fundamental principles of alloy engineering. The ORR kinetic activity, as prognosticated by theory, shows significant agreement with experimental results, provided that the rate-determining step (RDS) accounts for a dominant role in the potential-independent kinetic mechanism. In essence, alloy engineering manipulates electronic properties through electron transfer to modulate intermediate adsorption and adjusts the interface electric field (E_field) to regulate hydrogen atom transport, ultimately influencing kinetics. The E_field holds greater significance in ORR kinetics compared to the intermediate adsorption (E_ads^O), the corresponding degrees of correlation with free energy barriers (E_a) of RDS are -0.89, and 0.75, respectively. This work highlights the nature of alloy engineering for ORR kinetics modulation and assists in the design of efficient catalysts.