Electrochemical Biosensor Based on Nano TiO2 Loaded with Highly Dispersed Photoreduced Nano Platinum

Abstract

Precious metal nanomaterials have been widely used in electrochemical sensors. Further improving the dispersion of nanomaterials is beneficial to improving sensor performance and reducing the usage of noble metals. In this work, platinum nanoparticles (NPs) were loaded onto titanium dioxide nanoparticles (TiO2) by the photoreduction method. The morphology, content, and distribution of NPs were determined by high resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS). The method has simple steps and a short synthesis time (14 min). NPs with an average particle size of about 5 nm were uniformly dispersed on the surface of TiO2 nanoparticles. The nano Pt loaded TiO2 (Pt/TiO2) nanocomposites were modified on the surface of the glassy carbon electrode, and an enzyme-free H2O2 sensor was constructed and used as a carrier of lactate oxidase to prepare an amperometric lactic acid biosensor. The enzyme-free H2O2 sensor has a wide detection range (0.002–15 mM), a low detection limit (0.92 μM), and has a rapid response time (2 s) toward H2O2 with a relative standard deviation (RSD) of less than 3%. At the same time, the constructed lactic acid biosensor has a linear detection range of 0.003–0.7 mM and a detection limit of 3 μM toward lactate.