Nanoporous Cauliflower-like Pd-Loaded Functionalized Carbon Nanotubes as an Enzyme-Free Electrocatalyst for Glucose Sensing at Neutral pH: Mechanism Study

Abstract

In this work, we propose a novel functionalized carbon nanotube (f-CNT) supporting nanoporous cauliflower-like Pd nanostructures (PdNS) as an enzyme-free interface for glucose electrooxidation reaction (GOR) in a neutral medium (pH 7.4). The novelty resides in preparing the PdNS/f-CNT biomimetic nanocatalyst using a cost-effective and straightforward method, which consists of drop-casting well-dispersed f-CNTs over the Screen-printed carbon electrode (SPCE) surface, followed by the electrodeposition of PdNS. Several parameters affecting the morphology, structure, and catalytic properties toward the GOR of the PdNS catalyst, such as the PdCl2 precursor concentration and electrodeposition conditions, were investigated during this work. The electrochemical behavior of the PdNS/f-CNT/SPCE toward GOR was investigated through Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and amperometry. There was also a good correlation between the morphology, structure, and electrocatalytic activity of the PdNS electrocatalyst. Furthermore, the LSV response and potential-pH diagram for the palladium–water system have enabled the proposal for a mechanism of this GOR. The proposed mechanism would be beneficial, as the basis, to achieve the highest catalytic activity by selecting the suitable potential range. Under the optimal conditions, the PdNS/f-CNT/SPCE-based biomimetic sensor presented a wide linear range (1–41 mM) with a sensitivity of 9.3 µA cm−2 mM−1 and a detection limit of 95 µM (S/N = 3) toward glucose at a detection potential of +300 mV vs. a saturated calomel electrode. Furthermore, because of the fascinating features such as fast response, low cost, reusability, and poison-free characteristics, the as-proposed electrocatalyst could be of great interest in both detection systems (glucose sensors) and direct glucose fuel cells.

A sensitive and facile electrochemical paper-based sensor for glucose detection in whole blood using the Pd/CB-Ni@rGO modified electrode

“…For instance, Pd nanostructures (PdNs) supported by functionalized carbon nanotubes (f-CNTs) exhibiting cauliflower-like features have been investigated. 15 Despite having a large linear range, this sensor has poor selectivity and low sensitivity. Additionally, the development of carbon nanotube-supported palladium-cobalt nanoparticles (Pd-CoCNTs), 16 nanoporous PdAuNi, Pd nanocomposites of MnO 2 (Pd/MnO 2 nanosheets), 17 and nitrogen-doped graphene modified with Pd nanoparticles and NiAl layered double hydroxide (Pd-NiAl-LDH-GS) 18 sensors, were developed for glucose oxidation in blood.…”

CuO/Cu/rGO nanocomposite anodic titania nanotubes for boosted non-enzymatic glucose biosensors

“…At present, non-enzymatic glucose biosensors serve as the next generation of glucose biosensors by utilizing functionalized nanostructured materials for the straightforward electrocatalysis of glucose oxidation. 5,6…”

“…At present, nonenzymatic glucose biosensors serve as the next generation of glucose biosensors by utilizing functionalized nanostructured materials for the straightforward electrocatalysis of glucose oxidation. 5,6 The selection and fabrication of nanostructured and electrocatalytic materials are essential steps for non-enzymatic glucose sensors. Numerous attempts have been made to develop nanostructured materials as electrodes to enhance the oxidation rate and durability of active nanostructured materials, such as metals, 7,8 metal alloys, 9,10 metal oxide, 11,12 composite materials 13,14 and carbon-based nanocomposite.…”

An amphiphilic polyoxometalate–CNT nanohybrid as a highly efficient enzyme-free electrocatalyst for H2O2 sensing

“…1 Different types of amphiphilic materials based on fullerenes, metals, metal oxides/cyanates, copolymers, MOFs, and many others have been explored for electrocatalysis, electrochemical sensing and energy-related applications. [2][3][4][5][6][7] Polyoxometalates (POMs), a class of distinct molecular clusters, are promising materials for engineering new amphiphilic substances for specific applications, owing to their diverse structures, excellent intrinsic catalytic properties, and decent interacting capacity with other molecules. [8][9][10][11][12][13][14] POM nanoclusters have therefore been widely explored in various catalytic reactions.…”