Black Phosphorene and Tricobalt Tetraoxide Nanocomposite Modified Electrode for Investigating Direct Electrochemistry and Electrocatalytic Behavior of Horseradish Peroxidase

To overcome the instability of black phosphorene (BP) and enhance direct electron transfer of heme proteins for electrochemical sensing, an electrostatic self‐assembled Co 3 O 4 ‐BP nanocomposite was prepared and subsequently employed to construct an enzymatic biosensor by immobilizing horseradish peroxidase (HRP) onto a carbon ionic liquid electrode (CILE). The Co 3 O 4 ‐BP nanocomposite was examined in terms of its structural features and physicochemical characteristics by SEM, TEM, FT‐IR, UV–‐vis, XRD, Raman, and XPS. The direct electron transfer behavior of HRP was examined by cyclic voltammetry. The appearance of quasi‐reversible and symmetric redox peaks confirmed that the Co 3 O 4 ‐BP‐modified electrode promoted electron transfer of the immobilized HRP. Nafion/HRP/Co 3 O 4 ‐BP/CILE exhibited superior electrocatalytic activity toward the reduction of trichloroacetic acid (TCA), NaNO 2 and H 2 O 2 with wide linear ranges (0.4–510.0 mmol/L for TCA, 0.7–39.7 mmol/L for NaNO 2 and 1.0–62.0 mmol/L for H 2 O 2 ) and low detection limits (0.13, 0.23, and 0.33 mmol/L, respectively). This work offers a promising strategy for stabilizing BP via metal‐oxide hybridization and provides an efficient sensing platform for real sample analysis with satisfactory results.