Electronic Modulation of Cu Sites via Iron Incorporation in Cu5FeS4 Bimetallic Sulfide for High-Efficiency Oxygen Reduction Reaction

en The sluggish kinetics of the oxygen reduction reaction (ORR) necessitate developing oxygen electrodes with enhanced electrocatalytic activity for practical zinc–air battery applications. In this study, an iron-doped copper sulfide electrocatalyst (CuFeNS-PNC) anchored on metal–organic framework-derived carbon substrates was designed, featuring a bimetallic Cu 5 FeS 4 architecture where iron electronically modulates copper sites. The performance enhancement of this copper–iron sulfide bimetallic system relative to a monometallic copper sulfide arises from synergistic Fe-Cu interactions, as confirmed by X-ray photoelectron spectroscopy (XPS), revealing electron transfer from iron to copper. Density functional theory (DFT) calculations demonstrate that iron incorporation downshifts the copper d-band center, weakening OH* adsorption energy to a more optimal level, thereby boosting ORR kinetics. Consequently, the CuFeNS-PNC catalyst achieves superior electrocatalytic performance with an ORR onset potential ( E onset ) of 0.988 V and a half-wave potential ( E 1/2 ) of 0.874 V, significantly surpassing commercial Pt/C and conventional metallic sulfide catalysts. When integrated into a zinc–air battery, it delivers a high open-circuit voltage (1.450 V), specific capacity (789 mAh g −1 ), and peak power density (117.9 mW cm −2 ). This work provides valuable guidelines for the rational design and synthesis of electronically modulated metallic sulfides to enhance ORR activity for energy storage and conversion applications. 摘要 zh 氧还原反应 (ORR) 的缓慢动力学过程限制了锌空气电池的实际应用, 因此开发具有优异电催化活性的氧电极材料至关重要。本研究设计了一种负载于金属有机框架衍生碳基底上的铁掺杂铜硫化物电催化剂 (CuFeNS-PNC) , 其结构为双金属Cu 5 FeS 4 , 其中铁元素通过电子调控作用调节铜活性位点。与单金属铜硫化物相比, 该双金属体系的性能提升源于Fe–Cu之间的协同作用。X射线光电子能谱结果表明, 存在从Fe向Cu的电子转移。密度泛函理论计算进一步揭示, 铁的引入使铜的d带中心下移, 优化OH*的结合强度, 进而加速ORR动力学过程。因此, CuFeNS-PNC催化剂表现出优异的电催化性能, 具有0.988 V的氧还原起始电位和0.874 V的半波电位, 显著优于商用Pt/C及常规金属硫化物催化剂。应用于锌空气电池时, 该催化剂实现了高达1.450 V的开路电压、789 mAh g⁻ 1 的比容量以及117.9 mW cm⁻²的峰值功率密度。本研究为通过电子结构调控设计高效金属硫化物催化剂以提升氧还原活性、促进能量存储与转换应用提供了有价值的指导。