High-index {hk0} facets platinum concave nanocubes loaded on multiwall carbon nanotubes and graphene oxide nanocomposite for highly sensitive simultaneous detection of dopamine and uric acid

Carbon materials and the metal nanocrystals enclosed by high-index facets have aroused considerable attention due to their large specific surface area, excellent electrical properties and catalysis activity, and easy accessibility for target molecules. In this study, the Pt concave nanocube (CNC) with high-index {410} and {510} facets was successfully prepared via a simple hydrothermal method. The multiwalled carbon nanotubes (MWCNT) and graphene oxide (GO) were chosen as the supporting materials to further improve the dispersion of Pt CNC and the electrical conductivity of nanocomposite. The nanocomposite was used to modify electrode for sensitive simultaneous detection dopamine and uric acid. The cyclic voltammetry and differential pulse voltammetry were applied to confirm the catalytic activity of proposed sensor. By using the as-synthesized nanomaterlal as nonenzymatic sensing material, dopamine and uric acid can be detected with high sensitivity and selectivity. The linear range towards dopamine sensing is from 0.8 to 300 mu M, and the limit of detection is 0.27 mu M. For uric acid sensing, the sensor exhibited over two wide linear ranges (from 1 mu M to 0.3 mM and from 0.3 mM to 1 mM) with a detection limit of 0.35 mu M. The sensor also possessed a long-term stability, good reproducibility and a promising application for electrochemical detection of both dopamine and uric acid in real samples.