Unraveling the activation insight of molecular oxygen in oxygen vacancy-enriched Cu/Cu₂O Schottky junctions with dual LSPR effect toward high-efficient NIR light-driven photothermal catalysis

The development of efficient near-infrared (NIR) light-driven Cu₂O-based photocatalysts and a deeper understanding of their underlying mechanisms for pollutant degradation are urgently needed. Herein, we report the rational design of oxygen vacancy-enriched Cu/Cu₂O Schottky junctions via H₂MoO₄-template-assisted liquid-phase reduction method. Under NIR irradiation, the optimized Cu/Cu₂O composite exhibits remarkable photothermal catalytic performance, achieving 85.1% degradation of tetracycline within 120 min. The enhanced activity is attributed to the synergistic effect of the Schottky junction, dual localized surface plasmon resonance (LSPR), and a unique “directional anchoring” mechanism for O₂ activation. First, the Schottky junction formed at the Cu/Cu₂O interface promotes efficient separation of photogenerated charges. Second, a dual LSPR effect, combining the intrinsic LSPR of Cu nanoparticles with the defect-state LSPR induced by oxygen vacancies, significantly enhances NIR light absorption and photothermal conversion efficiency. Most importantly, in-situ spectroscopic and density functional theory analyses reveal a unique “directional anchoring” mechanism for O₂ activation at the oxygen vacancy (OV)-Cu interface. In this process, O₂ is selectively captured at the OV–Cu dual sites, where electron transfer from the interface weakens the O–O bond, thereby facilitating the generation of reactive oxygen species. This work provides fundamental insights into the design of high-performance NIR-driven photothermal catalysts for environmental remediation.