High-temperature annealing is an effective way to heal the defects of graphene-based nanocarbons and enhance their crystallinity. However, the thermally induced vibration of the graphene building blocks often leads to unfavorable micro-, nano-structural evolution including layer stacking. Herein, the key structural factors to achieve highly crystalline graphene frameworks with desired microstructures upon annealing at 1800 °C is revealed. The structural changes of fullerenes, single-walled carbon nanotubes, and graphene-based porous frameworks are precisely analyzed by their structural parameters, such as the total number of graphene edge sites and precise graphene stacking structures, using a novel advanced vacuum temperature-programmed desorption technique up to 1800 °C. The stacked structure is differentiated into loose and tightly stacking, where the loosely stacked structure is found to induce further stacking at high-temperature. Moreover, a graphene framework with an inner space size of greater than 4–7 nm is beneficial to avoid structural change upon high-temperature annealing. These findings offer both a fundamental understanding of the solid-state chemistry of nanocarbons under high temperatures and a viable strategy for engineering edge-site free graphene frameworks with pre-designed microstructures.
Carbon-coated porous silica spheres (C/PSSs) are particles with uniform particle and mesopore sizes, on which a thin layer of carbon is uniformly deposited on the surface by chemical vapor deposition. The continuous carbon deposit over the mesopore network allows the C/PSS to be electrically conductive and more chemically stable over its traditional counterparts, such as PSS, porous carbons, and carbon electrodes. As homogeneous particles, C/PSS can also be arranged uniformly on an electrode by screen printing to construct macroscopic networks that facilitate the diffusion of substances. Herein, C/PSS was synthesized and fabricated into a working electrode for a prototype glucose enzyme sensor to perform electrochemical measurements on a sample size of 20 μL. We selected the two enzymes, glucose dehydrogenase (GDH) and glucose oxidase (GOD), and water-soluble mediators, quinoline-5,8-dione (QD), to demonstrate the functionality of the sensor. The GDH sensor achieved a linear response up to 75 mM glucose concentration much higher than commercial sensor strips and the GOD sensor up to 25 mM. The results proved that the response current was mainly controlled by glucose diffusion. We succeeded in developing a sensor chip with C/PSS arranged on the surface with high efficiency by selecting a mediator that can smoothly transfer electrons to and from carbon, which enables various sensing applications. This work is the demonstration of the triple pore structure of the C/PSS electrode for enzyme electrode reactions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.