Defect Density-Dependent pH Response of Graphene Derivatives: Towards the Development of pH-Sensitive Graphene Oxide Devices

Autor: Shayan Angizi, Xianxuan Huang, Lea Hong, Md Ali Akbar, P. Ravi Selvaganapathy, Peter Kruse
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Nanomaterials, Vol 12, Iss 11, p 1801 (2022)
Druh dokumentu: article
ISSN: 2079-4991
DOI: 10.3390/nano12111801
Popis: In this study, we demonstrate that a highly pH-sensitive substrate could be fabricated by controlling the type and defect density of graphene derivatives. Nanomaterials from single-layer graphene resembling a defect-free structure to few-layer graphene and graphene oxide with high defect density were used to demonstrate the pH-sensing mechanisms of graphene. We show the presence of three competing mechanisms of pH sensitivity, including the availability of functional groups, the electrochemical double layer, and the ion trapping that determines the overall pH response. The graphene surface was selectively functionalized with hydroxyl, amine, and carboxyl groups to understand the role and density of the graphene pH-sensitive functional groups. Later, we establish the development of highly pH-sensitive graphene oxide by controlling its defect density. This research opens a new avenue for integrating micro–nano-sized pH sensors based on graphene derivatives into next-generation sensing platforms.
Databáze: Directory of Open Access Journals