Engineering p–d Orbital Coupling and Vacancy-Rich Structure in Triatomic Iron–Bismuth–Iron Sites for Rechargeable Zinc–Air Batteries
Zhanhao Liang, Wencai Liu, Shaojie Jing, Yihui Huang, Bin Liao, Xinru Yan, Z. H. Qin, Xuchun Gui, Li‐Yong Gan, Hong Bin Yang, Dingshan Yu, Zhiping Zeng, Guowei Yang
Abstract
The rational design of heteroatomic sites with synergistic electronic modulation remains a critical challenge for achieving bifunctional oxygen electrocatalysis in sustainable energy technologies such as fuel cells and metal–air batteries. Herein, a triatomic Fe 2 BiN 5 configuration embedded in nitrogen-doped carbon (Fe 2 BiN 5 /C) with atomically dispersed FeN 2 –BiN–FeN 2 sites and vacancy-rich structures is synthesized via a pyrolysis and etching strategy. The triatomic architecture endows Fe 2 BiN 5 /C with exceptional bifunctional activity, delivering a high oxygen reduction reaction half-wave potential of 0.918 V and an oxygen evolution reaction overpotential of 245 mV at 10 mA cm –2, surpassing Pt/C and RuO 2 . In situ X-ray absorption fine structure and Raman spectroscopy reveal dynamic structural evolution during electrocatalysis, where Fe acts as the primary active center with Bi regulating the electron distribution via long-range interactions, thereby optimizing adsorption/desorption energetics of oxygen intermediates. The theoretical calculations further elucidate that the Bi-induced p–d orbital coupling leads to the alteration in Fe d-orbitals energy level, downshift d-band center, weaken binding strength to the oxygen-based intermediates, and reduced energy barrier for oxygen electrocatalysis. This work provides an understanding of bifunctional triatomic site with p-block metal as electronic modulators embedded in transition-metal atoms toward enhanced oxygen catalysis.