A Partially Graphitic Mesoporous Carbon Membrane with Three-Dimensionally Networked Nanotunnels for Ultrasensitive Electrochemical Detection

A hierarchically porous partially graphitic carbon (HPGC) membrane with three-dimensionally networked nanotunnels is prepared and applied as a monolithic matrix for electrochemical (bio)sensing. The walls of the nanotunnels (∼40–80 nm in diameter) are composed of partially graphitic carbon with ordered mesopores (∼6.5 nm in diameter). After modification with polydopamine, the HPGC membrane can be decorated with nanoparticles (i.e., Au NPs) and subsequently functions as a three-dimensional matrix for enzyme (i.e., glucose oxidase) immobilization. The Au NPs can accelerate electron transfer between the membrane electrode and enzyme and synergistically work with the enzyme in catalyzing glucose oxidation, thus considerably enhancing the sensitivity of the sensor. The signal intensity of the HPGC monolithic membrane electrode is ∼700 times higher than that obtained from mesoporous carbon/Nafion paste electrode counterparts. The limit of detection of the biosensor is 0.48 × 10 –11 M toward glucose detection, 4 orders of magnitude lower than that achieved by conventional nanostructured glucose sensors. The HPGC membrane shows potential in preparing monolithic electrodes for diverse electrochemical applications such as electrochemical detection, energy storage, and electrochemical catalysis.