Cu‐N 4 Single‐Atom Nanozyme with Multi‐Enzyme Mimetic Activities Combined with In 2 O 3 /Bi 24 O 31 Br 10 Heterojunction: Toward Sensitive Triple‐Mode Detection and Photocatalytic Inactivation of Vibrio Alginolyticus

In this study, a novel triple‐mode biosensor based on a Cu‐N 4 single‐atom nanozyme (Cu‐N 4 SAzyme) and an In 2 O 3 /Bi 24 O 31 Br 10 Z ‐Scheme heterojunction was constructed for the highly sensitive detection and photocatalytic inactivation of Vibrio alginolyticus ( V. alginolyticus ). The Cu‐N 4 SAzyme, possessing both ascorbate oxidase‐like and laccase‐like activities, was integrated with nucleic acid isothermal amplification technology. This integration enabled triple‐mode detection via photoelectrochemical (PEC), organic photoelectrochemical transistor biosensor (OPECT), and colorimetric (CL) methods, achieving a limit of detection (LOD, calculated) as low as 1.07 CFU/mL. An In 2 O 3 /Bi 24 O 31 Br 10 Z ‐Scheme heterojunction was fabricated as a photoactive gate electrode. Through UV‐vis diffuse reflectance spectrum ‐, Mott–Schottky, and electron spin resonance analyses, we conclude that the electron transfer mechanism is consistent with the proposed Z‐scheme mechanism, demonstrating that this structure exhibits highly efficient space charge separation and long carrier lifetime. Consequently, the photocurrent response was significantly enhanced, enabling highly sensitive triplex biosensing. Concurrently, the In 2 O 3 /Bi 24 O 31 Br 10 heterojunction was demonstrated to generate reactive oxygen species (ROS) under light irradiation, enabling the inactivation of a high concentration of V. alginolyticus (approximately 10 7.24 CFU/mL) within 3 h. This platform provides an integrated new strategy for both pathogen detection and disinfection.