Methylene blue intercalated layered MnO 2 nanosheets for high-sensitive non-enzymatic ascorbic acid sensor

Methylene blue intercalated layered MnO 2 nanosheets (MB-MnO 2 ) were synthesized through an ex-situ method at room temperature. Tetramethylammonium hydroxide (TMAOH) was used as a delaminating agent for the synthesis of nanosheet-like structures of MnO 2 . The prepared nanocomposites were analyzed by various instrumental techniques such as UV–visible, FTIR, XRD, FESEM, and EDX for the close examination of the morphology, structure, shape, crystallinity, and vibrational characterization. Typical two-dimensional layer sheet-like morphologies with multiple folds were observed for non-intercalated MnO 2 , whereas intercalated MnO 2 showed more flattered and planar square-shaped and elongated ultrathin sheet-like structures with occasional folds and crinkles. MB intercalated MnO 2 nanosheets were used as an efficient electron mediator for the electrooxidation of the ascorbic acid to dehydroascorbic acid. Cyclic voltammetry and chronoamperometry confirmed the excellent electrocatalytic activity of the modified MB intercalated MnO 2 nanosheets/GCE over a wide range of ascorbic acid concentrations in 0.1 M PBS. The detection limit was computed to be 0.05 μM. The effect of the scan rates and concentration of the ascorbic acid were also analyzed.