Hybridization of Co(3)S(4) and Graphitic Carbon Nitride Nanosheets for High-performance Nonenzymatic Sensing of H(2)O(2)

The development of efficient H(2)O(2) 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(2)O(2) sensor achieved through the hybridization of Co(3)S(4) and graphitic carbon nitride nanosheets (GCNNS). The Co(3)S(4) is synthesized via a hydrothermal method, and the bulk g-C(3)N(4) (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(3)S(4) is formed during nanosheet formation. Compared to the performances of pure components, the hybrid structure demonstrates excellent electroreduction towards H(2)O(2). We investigate the H(2)O(2)-sensing performance of the composite by cyclic voltammetry, differential pulse voltammetry, and amperometry. As an amperometric sensor, the Co(3)S(4)/GCNNS exhibits high sensitivity over a broad linear range from 10 nM to 1.5 mM H(2)O(2) 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(2)O(2) in real samples. The remarkable enhancement of the electrocatalytic activity of the composite for H(2)O(2) reduction is attributed to the synergistic effect between Co(3)S(4) and GCNNS.