Exploring the Complex and Diverse World of Carbon Electrochemistry - Unraveling the Interplay Between Structure-Property Relationships

Carbonaceous nanomaterials are a versatile group of materials that have gained significant interest in various technological fields, particularly in electroanalytical applications for healthcare. Sensor technologies that rely on electrochemical detection can obtain real-time information from patients, enabling more accurate diagnostics and personalized medical treatments. However, tocreate sensor materials that meet the necessary requirements for sensitivity and specificity, the sensor development must be grounded in a fundamental understanding of how material properties impact electroanalytical performance. Unfortunately, this understanding is generally lacking for carbon nanomaterials. In fact, there is a dearth of systematic assessments of the structural and electrochemical properties of carbon electrodes or assemblies built with carbon nanomaterials. This obstacle presents a significant challenge to the development of reliable carbonaceous electrodes in the near future. In this dissertation, we aim to solve this deadlock by conducting an extensive analysis of the structural, chemical, and electrochemical properties of various carbon allotropes and aim toconnect the observed electrochemical performance to the known physicochemical structure. Our investigation includes the following materials: amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), glassy carbon (GC), pyrolytic carbon (PyC), carbon nanofibers (CNF), multi-walled carbon nanotubes (MWCNT), and single-walled carbon nanotubes (SWCNT). Materials that contain residual metals catalysts from the growth process, we address the role of these catalysts in relation to the electrocatalytic properties of carbon nanomaterials. Along with the fundamental characterization of these materials, we also focus on SWCNT networks. This crystalline materialis used to demonstrate the impact of structural and chemical changes on its electrochemical performance, especially in the case of biomolecules. The work presented here demonstrates the versatile electrochemical properties exhibited by various carbon allotropes. Noticeable differences are seen in double-layer capacitance, pseudocapacitance, solvent potential windows, and especially, in reaction kinetics with surfacesensitive biomolecules. Even minor physicochemical changes in the same carbon nanomaterialSWCNT, such as the oxidation state of Fe particles, have substantial impact on electrochemical biomolecule detection. Thus, it is important to customize the properties of carbon nanomaterials to suit their intended applications. However, due to the complex nature of the interactions occurring at the electrode surface, it is challenging to determine the exact properties required for specific applications. Nevertheless, based on this study, we argue that the reaction kinetics of carbon nanomaterials can be improved by (i) possessing a porous structure that enables a thin film liquid layer effect, (ii) containing residual metal particles that can catalyze redox reactions, and (iii) having favorable surface chemistry.

Department dc:contributor.department

Sähkötekniikan ja automaation laitos

Grantor dc:publisher

Aalto University

Year dc:date.issued

2023

Author dc:creator

• Leppänen, Elli

Advisor dc:contributor.advisor

• Laurila, Tomi, Prof., Aalto University, Department of Electrical Engineering and Automation, Finland

Contributors dc:contributor

• Aalto-yliopisto
• Aalto University

Language dc:language.iso

en

Repository record dc:identifier.uri

https://aaltodoc.aalto.fi/handle/123456789/122316

OAI record oai:identifier

https://aaltodoc.aalto.fi/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aaaltodoc.aalto.fi%3A123456789%2F122316