"In situ" and "in operando" characterization techniques on surfaces of nanostructured carbon materials

• Grant number: 23/06233-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): July 01, 2023
• Effective date (End): June 30, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Evaldo Jose Corat
• Grantee: Laís Gimenes Vernasqui
• Host Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovações (Brasil). São José dos Campos , SP, Brazil
• Associated research grant: 19/18572-7 - New carbon materials: their relevant space, environmental and relevant spin off applications, AP.TEM

Abstract

Nanostructured carbon materials, in our most basic research work, are being studied as superhydrophobic and superhydrophilic materials, as supercapacitor materials, as catalyst supports, in addition to their interaction with biological media. All these processes are dependent on surface interactions with the respective media, both through morphological changes and through changes in the chemical composition of the surface. In the current research situation, the surface characterizations are carried out before and after the processes, creating only a notion of its state in these two conditions, with only inference of what happened during the process. In this proposal, we intend to implement "in situ" characterization techniques that can characterize in real time the surface modifications "in operando". For surface characterization in electrochemical processes, where chemical modifications of the surface are expected, an electrochemical cell will be made with an optical window that gives access by microscope to the surface of the sample under analysis. This electrochemical cell driven by a potentiostat, capable of doing voltammetry and chronoamperometry, will be analyzed with temporal resolution, both in our Raman microscope and in our FTIR/ATR microscope. For processes that depend on morphological modifications, such as superhydrophobicity transitions from Cassie-Baxter to Wenzel, lotus effect or petal effect, we will initially be limited to low magnification analyses, in microscopy and optical stereometry, but with excellent visualization of the state of wettability, directly on the surface. In parallel with these own implementations, which will give us experience in "in operant" characterization and knowing the time scale of these processes, we will start joint studies at CNPEM with the objective of using its installed experience in several X-ray analyses, in addition to system from scanning electronic microscopy in an environmental chamber.We want to progress to the use of NAP/XPS (Near Atmospheric Pressure X-ray Photoelectron spectroscopy), which is expected to be installed in the next few years on Sirius.