Gold-Nanoparticle-Decorated Titanium Nitride Electrodes Prepared by Glancing-Angle Deposition for Sensing Applications

Titanium nitride (TiN) and gold (Au)-decorated TiN nanorod array electrodes were fabricated on Au substrates using glancing-angle deposition (GLAD), and the electrochemical properties of these materials were investigated in potassium chloride and buffered solutions containing potassium ferricyanide, ascorbic acid, uric acid, and dopamine. Cross-sectional scanning electron microscopy images depict an array of vertical nanocolumns that are ∼30 nm in width and ∼300 nm in height with sharp pointed apexes. The atomic percent ratio of N to Ti is 40:60, as revealed by X-ray photoelectron spectroscopy. Decoration of the GLAD-produced TiN nanorods with Au nanoparticles reduces the width between nanocolumns from ∼23 to ∼15 nm and improves the electroactivity of the electrodes. The capacitive current in potassium chloride increases by a factor of 2, and the electron-transfer rate of potassium ferricyanide increased by 4. The addition of Au nanoparticles to the TiN nanorod support also significantly improves the electrodes’ responsiveness to electroactive biomolecules such as ascorbic acid, uric acid, and dopamine. Overall, these results indicate that TiN nanorod array electrodes prepared by GLAD have promise in the electrochemical analysis of electroactive biomolecules and applications in electrocatalysis, particularly when decorated with Au.