High‐Performance Amperometric Sensors Using Catalytic Platinum Nanoparticles‐Thionine‐Multiwalled Carbon Nanotubes Nanocomposite

Thionine (TH) adsorbed on multiwalled carbon nanotubes (MWCNTs) increases the load and dispersion of platinum nanoparticles (PtNPs) generated by chemical reduction of H 2 PtCl 6 with NaBH 4 . Under the optimum conditions, the PtNPs‐TH‐MWCNTs/Au electrode electrocatalyzed the reduction and oxidation of H 2 O 2 with high sensitivity, and after glucose oxidase (GOx) adsorption it responded to glucose concentration with a sensitivity of 0.14 A M −1 cm −2 . The cyclic voltammetric cathodic peak current for NO 2 − reduction on PtNPs‐TH‐MWCNTs/Au responded linearly to NO 2 − concentration from 0.5 to 150 µM, with a sensitivity of 5.52 A M −1 cm −2 and a detection limit of 0.2 µM.