Layered
double hydroxides (LDH) belong to the class of two-dimensional
materials having a wide variety of applications ranging from energy
storage to catalysis. Often, these materials when used for nonenzymatic
electrochemical glucose sensing tend to be interfering with oxygen
evolution reaction (OER), resulting in overestimation of the glucose.
Herein, to address this, NiFe-based LDH were selected because of their
ability to vary the metal ratios. The synthesized LDH have been characterized
using various spectroscopic and microscopic techniques. Among the
LDH synthesized, Ni4Fe-LDH have been able to differentiate
the glucose oxidation potential and the onset potential of OER with
minimum interference. The Ni4Fe-LDH sensor shows a sensitivity
of 20.43 μA mM–1 cm–2 in
the linear range of 0–4 mM concentrations. To further enhance
the sensitivity, composites of reduced graphene oxide (rGO) have been
synthesized in situ, and the Ni4Fe/rGO5 composites
have shown an increased sensitivity of 176.8 μA mM–1 cm–2 attributed to the charge-transfer interactions.
To understand the experimental observations, detailed computational
studies have been carried out to study the effect of the electronic
structure on the metal ratios of the LDH and its role in differentiating
glucose sensing and the oxygen evolution reaction. Along with this,
theoretical calculations are also carried out on LDH–graphene
composites to study the charge-transfer interactions.