Photoenhanced Peroxidase-Like Activity of Co₃V₂O₈–TiO₂ Heterojunction for Colorimetric Determination of Neomycin

Although nanozymes are widely applied in many aspects, achieving multi-enzyme activity and further improving catalytic activity via light illumination are paid attention on. In this work, the Co3V2O8–TiO2 type II heterojunction has been successfully synthesized by in-suit growth Co3V2O8 on the template of TiO2 with the peculiarly urchin-like morphology. Compared with Co3V2O8 and TiO2 individually, Co3V2O8–TiO2 exhibits dual-nanozyme activity, including the oxidase-like (OXD) and peroxidase-like (POD) activity under light illumination. The heterojunction of Co3V2O8–TiO2 is beneficial to the electron–hole separation and then accelerates electron transfer between substrates under light illumination. Abundant reactive oxygen species (O2•–, 1O2, and •OH) produced during the catalytic process contribute to the excellent catalytic activity of the Co3V2O8–TiO2 nanozyme. As expected, the Co3V2O8–TiO2 nanozyme can be used to construct a facile, convenient colorimetric sensing platform for rapid detection of H2O2 and neomycin in a good linear range of 10–80 μM and 20–90 μM with a limit of detection (LOD) of 1.98 and 8.82 μM, respectively.