Structural Phase Transition of Mo2C for Enhancing Electrochemical Sensing of Hydrogen Peroxide

Abstract

Regulating the electrocatalytic activity of metal carbides is the key to achieving highly sensitive electrochemical sensing. Molybdenum carbide (Mo2C) nanoparticles were anchored on the surface of nitrogen doped carbon nanomaterials (NC) through polymerization and calcination. By adjusting the calcination conditions, the crystal phase structure of Mo2C nanoparticles was successfully regulated, and two kinds of Mo2C nanoparticles with different crystal phase structure were obtained. The effect of the crystal structure of Mo2C on the electrocatalytic reduction of H2O2 was investigated. The results show that Mo2C with the hexagonal structure (H-Mo2C) has higher electrocatalytic activity for H2O2 reduction reaction, and the sensor based on H-Mo2C/NC could detect H2O2 in a wide linear range from 0.02 mM to 7.1 mM with a high sensitivity of 282.9 μA·mM−1·cm−2 and a low detection limit of 0.45 μM (S/N = 3). Moreover, the sensor can also accurately determine the content of H2O2 in disinfectant and milk samples. This study demonstrated Mo2C with the hexagonal structure as an effective sensing material for H2O2.