Regulating electron effect by interface-induced dislocation in Fe2P/Fe to accelerate oxygen reduction reactions

Abstract

Achieving precise control of the electronic environment of transition metal compounds is important for improving the efficiency of electrocatalytic oxygen reduction reaction (ORR) but continues a formidable challenge. Herein, we present a novel Fe₂P/Fe heterostructure catalyst with abundant dislocation defects, where the oxidation state of Fe shift from 0.11 to 0.97, leading to an enhanced ORR performance. In situ FTIR and DFT showed that the dislocation-rich heterojunction catalysts enhanced the desorption of ∗OOH intermediates, facilitated the hydrogenation process of ∗O, and improved the kinetic process of the 4e⁻ reaction. Consequently, the developed Fe₂P/Fe catalyst exhibited a mass activity of 164.3 A g_metal⁻¹, which is over three times greater than the traditional Pt/C catalyst that measured 53.6 A g_metal⁻¹, highlighting its remarkable efficacy. This significant activity enhancement was accompanied by 99.56 % 4e⁻ selectivity and half-slope potential (E_1/2 = 0.90 V). In addition, the catalyst also performs excellent power density (150.4 mW cm⁻²) in zinc-air batteries (ZABs) and maintains long-term stability after 130 h of continuous charging and discharging. This work on dislocation-rich non-noble metal catalysts provides new insights into oxygen reduction catalysts.