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 Co 3 V 2 O 8 –TiO 2 type II heterojunction has been successfully synthesized by in-suit growth Co 3 V 2 O 8 on the template of TiO 2 with the peculiarly urchin-like morphology. Compared with Co 3 V 2 O 8 and TiO 2 individually, Co 3 V 2 O 8 –TiO 2 exhibits dual-nanozyme activity, including the oxidase-like (OXD) and peroxidase-like (POD) activity under light illumination. The heterojunction of Co 3 V 2 O 8 –TiO 2 is beneficial to the electron–hole separation and then accelerates electron transfer between substrates under light illumination. Abundant reactive oxygen species (O 2 •–, 1 O 2, and •OH) produced during the catalytic process contribute to the excellent catalytic activity of the Co 3 V 2 O 8 –TiO 2 nanozyme. As expected, the Co 3 V 2 O 8 –TiO 2 nanozyme can be used to construct a facile, convenient colorimetric sensing platform for rapid detection of H 2 O 2 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.