Black phosphorene‐poly‐lysine nanocomposites‐based horseradish peroxidase biosensor for sensitive electrochemical detection of sodium nitrite

In the paper, black phosphorene (BP) was stabilized with poly‐lysine (PLL) to form a composite material, which was then utilized to modify a carbon ionic liquid electrode (CILE). The morphology and structure of PLL‐BP was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). A novel electrochemical method for sodium nitrite (NaNO₂) analysis was established by further immobilizing horseradish peroxidase (HRP) on the modified CILE. The electrochemical behavior of the Nafion/HRP/PLL‐BP/CILE system was characterized by cyclic voltammetry, exhibiting a pair of distinct and well‐defined redox peaks. Excellent electrocatalytic performance for NaNO₂ reduction was observed with the developed electrochemical HRP biosensor, covering a concentration range from 0.2 to 14.7 mmol/L and a detection limit of 0.067 mmol/L (3σ). The detection results of the actual samples were satisfactory, which demonstrated the potential application of this electrochemical HRP biosensor.