Abstract
This work outlines a synthetic strategy inducing the microwave-assisted synthesis of palladium (Pd) nanocrystals on a graphite sphere (GS) and reduced graphene oxide (rGO) supports, forming the Pd catalysts for non-enzymatic glucose oxidation reaction (GOR). The pulse microwave approach takes a short period (i.e., 10 min) to fast synthesize Pd nanocrystals onto a carbon support at 150 °C. The selection of carbon support plays a crucial role in affecting Pd particle size and dispersion uniformity. The robust design of Pd-rGO catalyst electrode displays an enhanced electrocatalytic activity and sensitivity toward GOR. The enhanced performance is mainly attributed to the synergetic effect that combines small crystalline size and two-dimensional conductive support, imparting high accessibility to non-enzymatic GOR. The rGO sheets serve as a conductive scaffold, capable of fast conducting electron. The linear plot of current response versus glucose concentration exhibits good correlations within the range of 1–12 mM. The sensitivity of the Pd-rGO catalyst is significantly enhanced by 3.7 times, as compared to the Pd-GS catalyst. Accordingly, the Pd-rGO catalyst electrode can be considered as a potential candidate for non-enzymatic glucose biosensor.
Highlights
The development of sensitive and stable glucose biosensors, based on an electrochemical technique, has motivated scientists and researchers due to the practical need for monitoring blood sugar [1,2]
Based on the glucose oxidation reaction (GOR) mechanism, the glucose detection is generally divided into two types: enzymatic glucose and non-enzymatic glucose sensors [8]
This work outlined a synthetic strategy allowing the preparation of Pd nanocrystals on graphite sphere (GS) and reduced graphene oxide (rGO) supports, forming the Pd catalysts toward non-enzymatic GOR
Summary
The development of sensitive and stable glucose biosensors, based on an electrochemical technique, has motivated scientists and researchers due to the practical need for monitoring blood sugar [1,2]. The detection limits of glucose sensors via the electrochemical route well suit the blood glucose range of healthy individuals and diabetic patients (1.1–20.8 mM) [6,7]. Based on the glucose oxidation reaction (GOR) mechanism, the glucose detection is generally divided into two types: enzymatic glucose and non-enzymatic glucose sensors [8]. Traditional glucose sensors on the market are mainly based on glucose oxidase-assisted electrochemical oxidation, that is, enzymatic glucose [9]. Despite its high selectivity and sensitivity, the enzymatic glucose sensor still suffers from some drawbacks such as expensive enzymes, the requirement of a complex and tedious enzyme immobilization process, and instability due to the inherent fragility of enzymes [9,10]. The non-enzymatic glucose sensor, based on direct electrocatalytic oxidation, has gradually been emerging and is expected to Sensors 2017, 17, 2163; doi:10.3390/s17102163 www.mdpi.com/journal/sensors
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