Nitrogen-doped hierarchical porous carbon nanomaterial from cellulose nanocrystals for voltammetric determination of ascorbic acid

Abstract The sensing application of cellulose nanocrystals (CNCs) is fascinating. CNCs can’t produce electrical or optical signals directly. Different from published sensing methods, a novel and simple electrochemical sensor for sensitive and selective detection of ascorbic acid (AA) was constructed based on three-dimensional nitrogen-doped hierarchical porous carbons (NHPC) by carbonizing CNCs and urea. Compared with bare glassy carbon electrode (GCE), the presence of porous carbons effectively increases the electron transport between analytes and the electrode, and significantly reduces the overpotential of AA oxidation. Under the optimum conditions, the electrode comprised of NHPC exhibits an extremely wide linear range from 8 × 10−5 to 1 × 10−2 M (R2 = 0.9996) and 1 × 10−6 to 5 × 10−5 M (R2 = 0.9867) to recognize the AA molecules, with a low detection limit of 2.45 × 10−7 M (S/N = 3) at a sensitivity of 0.1138 μA μM−1 cm−2. In particular, the sensing system for AA detection was further verified by the successful monitoring of AA in some spiked real samples. The fabricated nitrogen-doped CNC-based porous carbon material shows broad potential in the electrochemical application.