Metal-organic framework derived in-situ 3D porous CuS@carbon octahedron for enhanced electrochemical detection of ascorbic acid

Abstract

Sensitive and reliable detection of the antioxidant ascorbic acid (AA) is crucial for biosensing and food safety applications. Herein, CuS/carbon composites (CuS@C-c) with porous octahedral structure were successfully fabricated by pre-carbonization and then sulfidation of the precursor Cu-MOF templates, which allowed for the in-situ encapsulation of CuS into the carbon matrix, simultaneously endowing the CuS@C-c with high conductivity and rigid structure protection. Benefiting from the unique structural features, the CuS@C-c displayed significantly improved electrochemical performance compared with hydrothermal disordered structural products (CuS@C-h). The CuS@C-c was employed for preparing the modified electrode and exhibited distinguished electrocatalytic oxidation of AA with a wide linear range of 0.1–1000.0 μmol/L and a low detection limit of 0.03 μmol/L, which could be attributed to synergistic contributions of CuS and carbon matrix, as well as their unique 3D open porous structure, which provided abundant accessible active sites and accelerating electron transfer. The developed electrode showed good anti-interference ability, long-term stability, and reproducibility and was able to efficiently detected AA contents in pharmaceuticals and human urine samples with acceptable recoveries.