Sulfur-doped Co(OH)2 nanosheets with abundant oxygen vacancies for high-performance non-enzymatic glucose sensing

The development of high-performance materials for electrochemical non-enzymatic glucose sensing is crucial for diabetes detection and management. This study presents a facile approach for synthesizing sulfur-doped Co(OH)2 nanosheets with abundant oxygen vacancies, enhancing glucose sensing capabilities. Initially, ultrathin Co(OH)2 nanosheets are synthesized via a dissolution-recrystallization process, facilitated by L-lysine during hydrothermal synthesis. Subsequently, sulfur-doped Co(OH)2 nanosheets with oxygen vacancies (B-S-Co(OH)2) are produced through a two-step modification process using Na2S and NaBH4. The resulting B-S-Co(OH)2 exhibits high specific surface area, numerous oxygen vacancies, and rapid electron transfer, contributing to increased electrochemical activity. Electrochemical measurements, conducted with a glassy carbon rotating disk electrode (RDE), indicate low charge transfer barriers and enhanced redox properties. Consequently, B-S-Co(OH)2 nanosheets demonstrate superior glucose sensing performances, characterized by rapid response, high sensitivity (1.044 mA·mM–1·cm–2), broad linear range (0.01–1.4 mM and 1.6–3.6 mM), low detection limit (2.4 µM), and excellent long-term stability. This study offers an effective method for modifying the electronic structure and charge transfer properties of Co(OH)2 through surface modification, thereby advancing non-enzymatic glucose sensing capabilities.