Hierarchical AgO-CuO heterostructured nanowire bundles with optimized electronic structure for efficient oxygen evolution electrocatalysis

To overcome the limitations of low activity and poor stability of catalysts in oxygen evolution reaction (OER), this study developed a hierarchical heterostructural AgO-CuO/Cu nanowire bundles (NBs) self-supported electrode through room-temperature electrochemical synthesis of Cu NBs, followed by silver displacement, electrodeposition, and in-situ oxidation processes. The catalyst exhibits excellent OER performance, requiring overpotentials of only 200, 302, and 391 mV at current densities of 10, 100, and 500 mA cm −2 , respectively, with a low Tafel slope of 67 mV dec −1 . Remarkably, it demonstrates outstanding durability for 400 h at 100 mA cm −2 in 1.0 M KOH. The results of theoretical calculations indicate that the synergistic AgO-CuO heterointerface, in which the d-band center of AgO undergoes an upward shift due to the regulatory effect of CuO, significantly reduces the free energy barrier of the rate-determining step. Meanwhile, the self-supported hierarchical nanowire bundle architecture enables short oxygen diffusion pathways and reinforced structural durability. This dual optimization of electronic structure and mass transport provides an innovative strategy for designing binder-free electrocatalytic systems, offering valuable insights into energy conversion technologies.