RT Journal Article
T1 Exploring the charge carrier dynamics in carbon nanotubes-TiO2 composites for water photooxidation
A1 Peón-Díaz, Francisco J.
A1 Expósito Gálvez, Juan Carlos
A1 Segura del Río, Rodrigo
A1 Henríquez, Ricardo
A1 Anta, Juan
A1 Oskam, Gerko
K1 Oxidized carbon nanotubes
K1 Titanium dioxide
K1 Photoelectrochemical water splitting
AB Composite materials consisting of stable metal oxides and functionalized carbonaceous nanomaterials are attractive for application in a range of photocatalytic systems. Carbon nanotubes/titanium dioxide (CNTs/TiO2) composites have been shown to outperform TiO2 in photoelectrochemical applications, which has been attributed to efficient electron extraction from TiO2 by CNTs and subsequent fast electron transport. However, theunderlying mechanisms need to be clarified. In this work, we present a systematic study varying the CNTs content and comprehensively analyze the composite structure, morphology, crystallinity, light harvesting properties, and photoelectrochemical charge carrier dynamics. We show that the performance improvement observed for the composites depends in a complex manner on several parameters, including the CNTs content, the thickness of the TiO2 overlayer, the chemical capacitance of CNTs, and the hole transfer efficiency. Using intensity-modulated photocurrent spectroscopy in aqueous electrolyte solution both without and with 0.1 M Na2SO3 as hole capturing agent, we show that electron extraction and transport compete with the hole trapping, recombination, and transfer dynamics at the CNTs/TiO2 and TiO2/electrolyte interfaces. We show that the optimal performance is related to the change in charge extraction mechanism from a trap-limited diffusion scenario in TiO2 to a direct charge extraction in CNTs/TiO2 composite with optimal CNTs content and TiO2 thickness. These insights provide valuable guidance for the design and optimization of CNTs/TiO2 and similar composites for photoelectrochemical applications.
PB Elsevier
YR 2024
FD 2024-05-15
LK https://hdl.handle.net/10433/20705
UL https://hdl.handle.net/10433/20705
LA en
NO Francisco J. Peón-Díaz, Juan Carlos Expósito-Gálvez, Rodrigo Segura del Río, Ricardo Henríquez, Juan A. Anta, Gerko Oskam, Exploring the charge carrier dynamics in carbon nanotubes-TiO2 composites for water photooxidation, Catalysis Today, Volume 438, 2024, 114789, ISSN 0920-5861, https://doi.org/10.1016/j.cattod.2024.114789
NO Ministerio de Ciencia, Innovación y Universidades (Spain) [GrantPID2022–140061OB-I00]. Ministerio de Universidades and Universidad Pablo de Olavide, Beatriz Galindo Program [BEAGAL 18/00077 and grant BGP 18/00060]
NO Centro de nanociencia y tecnologías sostenibles (CNATS). Universidad Pablo de Olavide.
DS RIO
RD May 24, 2026