Abstract
A novel solvothermal technique has been developed in the presence of C/N/B precursor for synthesizing B-N-coped graphene quantum dots (GQDs) as non-metal electrocatalysts towards the catalytic glucose oxidation reaction (GOR). Both N-doped GQD and B-N-codoped GQD particles (~4.0 nm) possess a similar oxidation and amidation level. The B-N-codoped GQD contains a B/C ratio of 3.16 at.%, where the B dopants were formed through different bonding types (i.e., N‒B, C‒B, BC2O, and BCO2) inserted into or decorated on the GQDs. The cyclic voltammetry measurement revealed that the catalytic activity of B-N-codoped GQD catalyst is significantly higher compared to the N-doped GQDs (~20% increase). It was also shown that the GOR activity was substantially enhanced due to the synergistic effect of B and N dopants within the GQD catalysts. Based on the analysis of Tafel plots, the B-N-codoped-GQD catalyst electrode displays an ultra-high exchange current density along with a reduced Tafel slope. The application of B-N-codoped GQD electrodes significantly enhances the catalytic activity and results in facile reaction kinetics towards the glucose oxidation reaction. Accordingly, the novel design of GQD catalyst demonstrated in this work sets the stage for designing inexpensive GQD-based catalysts as an alternative for precious metal catalysts commonly used in bio-sensors, fuel cells, and other electrochemical devices.
Highlights
IntroductionNanostructured materials are an emerging class of nanomaterials that have gained significant attention since their physiochemical characteristics can be engineered and even enhanced compared to their corresponding bulk material properties [1]
The N-doped graphene quantum dots (GQDs) sample displays a quasispherical shape with an average diameter of ca. 4.0 nm
Such an ordered lattice morphology confirms the formation of graphitelike structure for the GQD samples [33]
Summary
Nanostructured materials are an emerging class of nanomaterials that have gained significant attention since their physiochemical characteristics can be engineered and even enhanced compared to their corresponding bulk material properties [1]. Nanostructured materials enable higher surface areas and enhanced surface energy [2,3]. The carbon-based nanostructured materials have been widely used for energy storage and sensing devices due to superior conductivity, biocompatibility, and higher surface areas [4,5,6,7]. Among various classes of nanostructured materials, the graphene quantum dots (GQDs) have received significant attention recently [8]. The capability of adjusting the bandgap within a relatively wide range through adjusting the size and structure of GQDs [9]
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