Ni/Al Layered Double Hydroxide and Carbon Nanomaterial Composites for Glucose Sensing

Abstract

Layered double hydroxides (LDHs) have been combined with graphene and/or carbon nanotubes to prepare new composite materials with fascinating electrochemical features. For the first time, this work describes the development of an electrosynthesis protocol that allows the deposition of thin films of a Ni/Al LDH on glassy carbon electrodes previously modified with carbon nanomaterials. Three different approaches (potentiostatic, galvanostatic and potentiodynamic) were investigated in order to identify the best procedure. In all cases the potentiodynamic synthesis exhibits better reproducibility than the potentiostatic one which is the most used in literature. The reliability of the synthesis protocol was evaluated by performing the LDH electrodeposition using glassy carbon electrodes modified with multiwalled carbon nanotubes and/or electrochemically reduced graphene oxide arranged in five configurations. XRD and SEM analysis confirmed the LDH formation. Cyclic voltammetry shows the graphene presence ensured a large electrochemically active area with values 3 times higher than the one observed for an LDH deposited on a bare glassy carbon.Moreover, impedance electrochemical spectroscopy highlights that carbon nanomaterials play a key role in reducing the charge transfer resistance. In fact, it decreases from 2800 KΩ recorded for LDH deposited on bare glassy carbon to about 600 Ω for the best composite material. The materials were tested for glucose electrooxidation which was exploited for the fabrication of a sensor with high sensitivity (2.6 A M -1 cm -2 for the best device) and low limit of detection (0.6 µM for the best device).

3D Flower-like NiCo Layered Double Hydroxides: An Efficient Electrocatalyst for Non-Enzymatic Electrochemical Biosensing of Hydrogen Peroxide in Live Cells and Glucose in Biofluids

“…28 Redox property of the LDH can be promoted using transition metals (such as Co, Ni, Mn, and Fe), which undergo a Faradaic reaction via an electrochemical pathway in an appropriate potential range. 29 The LDH materials can conduct electricity due to electron hopping between metal centers that are close together or due to displacement of ion outside or inside the material. Therefore, the LDH have been considered as pseudo capacitive materials to produce supercapacitors.…”

Synthesis and Characterization of Layered Double Hydroxides as Materials for Electrocatalytic Applications

“…In fact, the ratio of the two metals in the electrodeposited compound is not strictly the same as present in the electrolytic solution because of the concentration gradients originating during the synthesis, especially when a long potential pulse is applied. Our group [ 33 , 34 , 35 ] has demonstrated that the potentiodynamic approach, which is based on the application of few CV cycles in the cathodic potential range, provides a reproducibility of the deposit which is much better than the one achieved with either the galvanostatic or potentiostatic methods. This is due to the strong reduction of cations concentration gradients in the diffusion layer, which are typical of the potentiostatic approach, thus allowing the restoration of the initial concentrations at the electrode surface.…”

“…Therefore, the same strategies can be employed to enhance the sensors’ performance. Composite materials based on LDHs and carbon nanomaterials have been synthesized to fabricate sensors for enzyme-less detection of glucose [ 34 , 118 , 119 ], guanine [ 120 ], H 2 S [ 121 ], and dopamine [ 122 ] displaying superior performance thanks to the enhanced electrical conductivity. The sensor performances can be improved increasing the accessibility to the redox-active sites, if the conductive support is chemically modified with ultrathin LDH layers [ 123 , 124 , 125 ].…”

New Trends in Nanoclay-Modified Sensors

“…A smart example presented by Gualandi et al [79] consisted of the development of a new composite material with electrochemical features combining LDHs with graphene and/or carbon nanotubes. Many LDHs' applications are restricted because of their low electrical conductivity decay during device operation due to the volume change associated with a variation of the redox state of the material.…”