Bimetallic Layered Hydroxide Nitrate@Graphene Oxide as an Electrocatalyst for Efficient Non-Enzymatic Glucose Sensors: Tuning Sensitivity by Hydroxide-Regulated M₂(OH)_4–n(A^n–) Phases Derived from Solvent Engineering

Abstract

Owing to their high catalytic activity, transition metal hydroxides are promising electrocatalysts for non-enzymatic glucose sensors. The hydroxyl functionalities in Co 1−x Ni x hydroxide/mixed anionic hydroxides play a vital role in their electrochemical activation via conversion to an oxyhydroxide catalyst and thus impact their sensitivity to small molecule (glucose) oxidation. Herein, we report the rational synthesis of M 2 (OH) 4−n (A n− ) compositions (0 > n ≤ 2) with hydroxide (OH)rich and OH-deficient phases, viz., CoNi-hydroxide nitrate (CoNi-HN) and CoNi-hydroxide carbonate (CoNi-HC), by using different solvents of ethanol and water, under solvo/hydrothermal conditions, respectively. The OH-rich CoNi-HN phase exhibited enhanced pre-activation efficiency, which accelerated the glucose oxidation kinetics, and beneficial morphological features (flowerlike structures with interconnected nanosheets). The OH-rich CoNi-HN catalyst, which is the first report for a glucose sensor, exhibited superior sensing property with a high sensitivity of ∼136 μA mM −1 cm −2 . The structure−(sensing) property relationship was analyzed in detail by tailoring the morphology to form an OH-rich graphene oxide (GO) hybrid. The CoNi-HN/GO hybrid exhibited improved glucose oxidation, delivering a wide glucose-sensing range, with a sensitivity of ∼268 μA mM −1 cm −2 , a low detection limit of 28.5 μM (S/N = 3), and good selectivity. The excellent sensitivity of this hybrid was attributed to the synergism between the OH-rich CoNi-HN phase and the OH-rich interfaces between GO and CoNi-HN, as well as a unique flower-like morphology with interconnected nanosheets. Insights into the critical role of hydroxyl groups in the electrocatalytic performance of transition-metal-based catalysts have been emphasized in this work.

Reduced graphene oxide supported MXene based metal oxide ternary composite electrodes for non-enzymatic glucose sensor applications

“…The prepared complex showed a higher response as compared to bare Cu 2 O with a linear range of 16.65 mM of glucose concentration 34 . Similar process was reported in various literatures in which different combination of rGO with metal oxides have been studied to improve the sensing performance of non-enzymatic glucose sensor 17 , 35 – 38 . Although these composites have improved the sensitivity as compared to bare metal oxides, it still needs a lot of improvement in the linear range with high sensitivity to make it commercially viable.…”

Comparison of Electrocatalytic Performance of CuCo2O4 Nanorods and Nanospheres Decorated with Co3S4 Nanosheets for Electrochemical Sensing of Hydrogen Peroxide and Glucose in Human Serum

“…The FT-IR spectra of the synthesized samples are shown in Figure D and Figure S2B. For the CuCo 2 O 4 sample, the bands observed at 564 and 660 cm –1 can be related to the stretching vibrations of metal-oxygen M-O (M = Co and Cu) in CuCo 2 O 4 nanostructures. , After coating with Co 3 S 4 , the peaks that appeared at 1160 and 1640 cm –1 can be related to the bending vibration of sulfide groups in Co 3 S 4 . Moreover, the broad band that appeared at 3433 cm –1 can be ascribed to OH stretching vibrations of the adsorbed water molecules.…”

Partially Oxidized Carbon Nanomaterials with Ni/NiO Heterostructures as Durable Glucose Sensors

“…Nonenzymatic electrochemical glucose-sensing materials with high accuracy, sensitivity, and efficiency have been conveniently prepared based on relatively inexpensive and abundant transition metals (TMs) . Meanwhile, TM-based compounds, such as metal nitrides, oxides/hydroxides, phosphides, and so forth, have been demonstrated to provide rapid and sensitive responses toward glucose detection. − On the other hand, it is well known that TM-based coordination polymers show a wider range of applications. , They are often used as precursors and/or templates to fabricate metal–carbon nanomaterials with different structures and morphologies for energy storage as well as heterogeneous catalysis. − However, with the continuous reaction using TM-based electrocatalysts for long-term chemical sensing, their overall nanostructures would be gradually destroyed and degraded, resulting in a slow disappearance of active species . Therefore, nonenzymatic catalysts derived from TM-based coordination polymers need to be endowed with high activity as well as structural stability.…”