How to fit a response current-concentration curve? Part (Ⅱ): Synergy of heterogeneous PANI@Ni(OH)2/NF towards high performance glucose sensing and a general semi-empirical model

Abstract

• Utilized a flow of hydroxylation and polymerization to assemble NEGSs. • Advanced a heterogeneous PANI@Ni(OH) 2 /NF NEGS without any conductive adhesive. • PANI@Ni(OH) 2 /NF showed a high sensitivity in a wide glucose concentration range. • Set up a general semi-empirical model of current-concentration suitable for NEGSs. • The nonlinear i – c model significantly reduced errors caused by linear fitting. Herein a heterogeneous material PANI@Ni(OH) 2 /NF, hydroxylated nickel foam (NF) modified by polyaniline (PANI), was assembled via an easy-to-operate sequential method. The hydroxylation obviously improves the reaction rate from Ni(II) to Ni (III) and the modification notably decreases the interface resistance. Benefitting from the synergy of Ni(OH) 2 , NF, and PANI, by means of three-segment linear fitting, PANI@Ni(OH) 2 /NF shows a high sensitivity up to 2248.7 μA mM cm −2 , a low detection limit of 0.52 μM, and excellent selectivity for glucose sensing when the glucose concentration ( c R * ) is from 0.001 mM to 16.000 mM. Further, we deduced a general semi-empirical model to describe the relationship between current i ( c R * ) and c R * , which eliminated the errors near the junction of two adjacent lines obviously and boarded the detection range. By comparing with the multi-segment linear fitting and our previous formula, both the mean d -value of 0.164 mA and the SD of 0.0218 mA obtained from the model are the lowest, respectively. A similar comparison was carried out in literature data, and the results are also satisfactory.