Rational Design of a Graphene Oxide/TiO ₂ /Au Nanocomposite for the Electrochemical Detection of Acetaminophen: Mechanism and Synergistic Effect

In this work, we report on the rational design of a highly sensitive electrochemical sensor based on TiO2/Au nanoparticles and a graphene oxide (GO) nanocomposite. Through combined computational and electrochemical analyses, we demonstrate that stabilizing the reaction intermediate during the rate-determining step is crucial for enhancing the intrinsic catalytic properties of the nanocomposite toward acetaminophen detection. In particular, the oxygen-containing functional groups of GO play a key role in facilitating the electrochemical oxidation of acetaminophen. The sensing signal was further increased by doping TiO2/Au nanoparticles into the GO sheets, owing to the synergistic effects of the materials. The developed electrochemical sensor demonstrated a much lower detection limit (0.06 μM) than needed in biomedical applications and a wide linear range (1–100 μM). The fabricated electrochemical sensor was successfully employed in real blood serum samples, exhibiting high anti-interference capabilities and demonstrating its potential for detecting acetaminophen pollutants. This study provides valuable insights into the interactions between GO-based nanomaterials and acetaminophen, as well as other organic pollutants. By tailoring the oxygen content and fine-tuning the properties of GO-based nanocomposites to align with the analyte’s electronic structure and the reaction intermediate, researchers can fully exploit the potential of these materials as sensing interfaces.