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 MnO2 nanotubes (c-Ru/MnO2) as an electrocatalyst for boosting electrochemical nonenzymatic hydrogen peroxide (H2O2) sensing. c-Ru/MnO2 is synthesized based on a facile hydrothermal method, followed by cation exchange and calcination. The obtained c-Ru/MnO2 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 MnO2 nanotubes exhibit higher electrochemical surface area and faster electron transfer rate but also promotes the strong adsorption of H2O2 and optimizes the interactions with the key intermediates OOH*/OO*. Thanks to the synergistic effect between Ru nanoclusters and MnO2 nanotubes, the sensor based on c-Ru/MnO2 exhibits a low anode peak potential of 0.42 V and an extremely high sensitivity of 2967.9 μA mM–1 cm–2 toward H2O2. Therefore, c-Ru/MnO2 is demonstrated to be an advanced electrocatalyst for sensitive electrochemical sensing of H2O2.