Highly sensitive detection of hydrogen peroxide at a carbon nanotube fiber microelectrode coated with palladium nanoparticles

We report on a carbon nanotube (CNT) fiber microelectrode coated with palladium nanoparticles (PdNPs) and enabling electrochemical sensing of hydrogen peroxide (H₂O₂). The synergistic effects of the CNT fibers (good mechanical strength and large surface area) and of the PdNPs (high electrocatalytic activity) result in a microelectrode for H₂O₂ that exhibits a 2-s response time, a detection limit as low as 2 μM, a sensitivity of 2.75 A cm^-2 M^-1, and a linear response range from 2 μM to 1.3 mM (R = 0.9994). The sensor is also selective and not interfered by potentially competing species in biological fluids, thus representing an inexpensive but highly sensitive and selective microsensor for H₂O₂. [Figure not available: see fulltext.]