Ru Nanoclusters on MnO₂ Nanotubes for Boosting Electrochemical Nonenzymatic H₂O₂ Sensing

The development of a high-performance electrocatalyst is the key to the construction of highly sensitive electrochemical sensing methods. In this work, we design Ru nanoclusters supported on MnO 2 nanotubes (c-Ru/MnO 2 ) as an electrocatalyst for boosting electrochemical nonenzymatic hydrogen peroxide (H 2 O 2 ) sensing. c-Ru/MnO 2 is synthesized based on a facile hydrothermal method, followed by cation exchange and calcination. The obtained c-Ru/MnO 2 nanocomposite is characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. Electrochemical studies and theoretical calculations reveal that the anchoring of Ru nanoclusters not only makes MnO 2 nanotubes exhibit higher electrochemical surface area and faster electron transfer rate but also promotes the strong adsorption of H 2 O 2 and optimizes the interactions with the key intermediates OOH*/OO*. Thanks to the synergistic effect between Ru nanoclusters and MnO 2 nanotubes, the sensor based on c-Ru/MnO 2 exhibits a low anode peak potential of 0.42 V and an extremely high sensitivity of 2967.9 μA mM –1 cm –2 toward H 2 O 2 . Therefore, c-Ru/MnO 2 is demonstrated to be an advanced electrocatalyst for sensitive electrochemical sensing of H 2 O 2 .