Novel zero-valent copper/CuS heterojunction catalyst with sulfur vacancies for efficient removal of 17β-estradiol via on-site H2O2 generation and activation

Zero-valent metal catalysts are capable of generating hydrogen peroxide (H 2 O 2 ) through oxygen activation. However, their sensitivity to pH and tendency toward surface passivation considerably restrict practical applications. In this study, a ZVC/CuS heterojunction catalyst with sulfur vacancies was successfully fabricated via the hydrothermal method. The catalyst leveraged the synergistic effect between sulfur vacancies and lattice sulfur to first mediate oxygen adsorption on its surface, enabling efficient on-site H 2 O 2 generation and activation. Density functional theory (DFT) calculations confirmed that *OOH served as the key intermediate in the H 2 O 2 formation pathway. Under neutral conditions, the ZVC/CuS self-Fenton system enabled complete (100 %) removal of 17β-estradiol (E2). Electrochemical analyses revealed that the current density of ZVC/CuS was 2.1 times higher than that of ZVC, indicating a substantial enhancement in redox activity. DFT, Liquid chromatography-mass spectrometry (LC-MS) analysis combined with toxicity assessments were collectively employed to deduce the degradation pathways of E2, confirmed that the toxicity of the degradation products was significantly reduced compared to the original pollutants. Importantly, comprehensive experiments under various conditions consistently demonstrated high efficiency in removing pollutants, highlighting the practical potential of ZVC/CuS. This study not only provides a novel strategy to overcome the instability of ZVC but also establishes a highly efficient self-Fenton-like catalytic system that does not require exogenous oxidants.