Interfacial studies in CNT fibre/TiO\(_{2}\) photoelectrodes for efficient H\(_{2}\) production

• Published in: arXiv.org 2020-12
• Main Authors: Moya, Alicia, Barawi, Mariam, Alemán, Belén, Zeller, Patrick, Amati, Matteo, Monreal-Bernal, Alfonso, Gregoratti, Luca, Víctor A de la Peña O'Shea, Vilatela, Juan J
• Format: Article
• Language: English
• Subjects: Atomic layer epitaxy; Carbon nanotubes; Charge transfer; Charge transport; Chemical reactions; Electrochemical impedance spectroscopy; Graphene; Metal oxides; Photoelectrons; Silver chloride; Substrates; Surface area; Synchrotron radiation; Synchrotrons; Titanium
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2012.01109

An attractive class of materials for photo(electro)chemical reactions are hybrids based on semiconducting metal oxides and nanocarbons (e.g. carbon nanotubes (CNT), graphene), where the nanocarbon acts as a highly-stable conductive scaffold onto which the nanostructured inorganic phase can be immobilised; an architecture that maximises surface area and minimises charge transport/transfer resistance. TiO\(_{2}\)/CNT photoanodes produced by atomic layer deposition on CNT fabrics are shown to be efficient for H\(_{2}\) production (\(0.07 \mu mol/min\) \(H_{2}\) at \(0.2V\) \(vs Ag/AgCl\)), nearly doubling the performance of TiO\(_{2}\) deposited on planar substrates, with \(100 \%\) Faradaic efficiency. The results are rationalised based on electrochemical impedance spectroscopy measurements showing a large reduction in photoelectron transport resistance compared to control samples and a higher surface area. The low TiO\(_{2}\)/CNT interfacial charge transfer resistance (\(10 \Omega\)) is consistent with the presence of an interfacial Ti-O-C bond and corresponding electronic hybridisation determined by spatially-resolved Scanning Photoelectron Microscopy (SPEM) using synchrotron radiation.