| Summary: | The development of efficient H<sub>2</sub>O<sub>2</sub> sensors is crucial because of their multiple functions inside and outside the biological system and the adverse effects that a higher concentration can cause. This work reports a highly sensitive and selective non-enzymatic electrochemical H<sub>2</sub>O<sub>2</sub> sensor achieved through the hybridization of Co<sub>3</sub>S<sub>4</sub> and graphitic carbon nitride nanosheets (GCNNS). The Co<sub>3</sub>S<sub>4</sub> is synthesized via a hydrothermal method, and the bulk g-C<sub>3</sub>N<sub>4</sub> (b-GCN) is prepared by the thermal polycondensation of melamine. The as-prepared b-GCN is exfoliated into nanosheets using solvent exfoliation, and the composite with Co<sub>3</sub>S<sub>4</sub> is formed during nanosheet formation. Compared to the performances of pure components, the hybrid structure demonstrates excellent electroreduction towards H<sub>2</sub>O<sub>2</sub>. We investigate the H<sub>2</sub>O<sub>2</sub>-sensing performance of the composite by cyclic voltammetry, differential pulse voltammetry, and amperometry. As an amperometric sensor, the Co<sub>3</sub>S<sub>4</sub>/GCNNS exhibits high sensitivity over a broad linear range from 10 nM to 1.5 mM H<sub>2</sub>O<sub>2</sub> with a high detection limit of 70 nM and fast response of 3 s. The excellent electrocatalytic properties of the composite strengthen its potential application as a sensor to monitor H<sub>2</sub>O<sub>2</sub> in real samples. The remarkable enhancement of the electrocatalytic activity of the composite for H<sub>2</sub>O<sub>2</sub> reduction is attributed to the synergistic effect between Co<sub>3</sub>S<sub>4</sub> and GCNNS.
|
|---|