Radiative and Non-Radiative Recombination Pathways in Mixed-Phase TiO2 Nanotubes for PEC Water-Splitting

Yalavarthi, Rambabu; Naldoni, Alberto; Kment, Štěpán; Mascaretti, Luca; Tomanec, Ondřej; Schmuki, Patrik; Zbořil, Radek

doi:10.3390/catal9020204

Cited by 50 publications

(34 citation statements)

References 75 publications

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“…Alternatively, the measurement of transient photocurrents with chopped light chronoamperometry (CLCA) under potentiostatic conditions was utilized to deduce surface recombination rate constants. Moreover, photoelectrochemical methods such as intensity modulated photocurrent spectroscopy (IMPS), intensity modulated photovoltage spectroscopy (IMVS), and photoelectrochemical impedance spectroscopy (PEIS) under controlled light intensity radiation proved to be powerful tools for deducing electron and hole lifetimes and rate constants for charge transfer and recombination 20,21,[23][24][25] . Apart from these electrochemical methods the photoactivity of semiconducting powders and films has been very often analyzed by photometrically monitoring the photocatalyzed degradation of organic dyes such as methylene blue 26 .…”

Section: Figurementioning

confidence: 99%

“…There is broad agreement in the scientific community that the photocatalytic reaction rate for the different reaction schemes is adversely affected by a radiative or non-radiative recombination of photo-excited charge carriers [19][20][21] . However, it is very often not clear, if a fast electron-hole recombination or a slow charge diffusion to the reactive surface is the limiting factor for the reaction rate.…”

Section: Introductionmentioning

confidence: 99%

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Investigating and Correlating Photoelectrochemical, Photocatalytic, and Antimicrobial Properties of TiO2 Nanolayers

Seiß

Helbig

Lösel

et al. 2021

Preprint

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Semiconducting transition metal oxides such as TiO2 are promising photo(electro)catalysts for solar water splitting and photoreduction of CO2. Titania admixtures are also used in paints and building materials or as coating on window glass and medical devices, giving the modified materials antimicrobial, self-or even air-cleaning properties. Although TiO2 is an effective catalyst for all these applications, it is mechanistically important to distinguish between photoelectrocatalytic, photocatalytic and antimicrobial processes. In the former, TiO2 is usually electrically contacted as photoanode, i.e. only the oxidation reaction takes place at the titania surface. In the two latter applications, TiO2 works as heterogeneous catalyst and has to catalyze a complete redox cycle. The underlying common and diverging rate-determining photochemical and photoelectrochemical mechanisms are still not well understood. Here, we thus present a systematic structural, photoelectrocatalytic, photocatalytic and antimicrobial study to directly compare and correlate these properties. We prepared TiO2 thin films on flourine-doped tin oxide (FTO) substrates by a sol-gel spin-coating technique. The materials were annealed at temperatures between 200 and 600°C and their morphologies were studied by GIXRD, FESEM and EDX. Photoelectrochemical properties were measured by linear sweep voltammetry, photoelectrochemical impedance spectroscopy, chopped light chronoamperometry, and intensity modulated photocurrent/ photovoltage spectroscopy. For comparison, photocatalytic rate constants were determined by methylene blue and Escherichea coli degradation and correlated with the deduced photoelectrocatalytic parameters.

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Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigating and Correlating Photoelectrochemical, Photocatalytic, and Antimicrobial Properties of TiO2 Nanolayers

Seiß

Helbig

Lösel

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…Charge recombination dynamics is one of the serious issues in a photocatalyst. Regarding TiO 2 , with its indirect band gap, it is proposed that the recombination process occurs via non-radiative pathways and, thus, the lifetime of charge carriers in TiO 2 varies from picoseconds to milliseconds [36,37]. In addition, the observed relatively enhanced PC efficiency of TiO 2 can also be ascribed to its electron and hole trapping [38].…”

Section: Mechanics Of Tio 2 Photocatalysismentioning

confidence: 99%

Insights into the TiO2-Based Photocatalytic Systems and Their Mechanisms

2019

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Photocatalysis is a multifunctional phenomenon that can be employed for energy applications such as H2 production, CO2 reduction into fuels, and environmental applications such as pollutant degradations, antibacterial disinfection, etc. In this direction, it is not an exaggerated fact that TiO2 is blooming in the field of photocatalysis, which is largely explored for various photocatalytic applications. The deeper understanding of TiO2 photocatalysis has led to the design of new photocatalytic materials with multiple functionalities. Accordingly, this paper exclusively reviews the recent developments in the modification of TiO2 photocatalyst towards the understanding of its photocatalytic mechanisms. These modifications generally involve the physical and chemical changes in TiO2 such as anisotropic structuring and integration with other metal oxides, plasmonic materials, carbon-based materials, etc. Such modifications essentially lead to the changes in the energy structure of TiO2 that largely boosts up the photocatalytic process via enhancing the band structure alignments, visible light absorption, carrier separation, and transportation in the system. For instance, the ability to align the band structure in TiO2 makes it suitable for multiple photocatalytic processes such as degradation of various pollutants, H2 production, CO2 conversion, etc. For these reasons, TiO2 can be realized as a prototypical photocatalyst, which paves ways to develop new photocatalytic materials in the field. In this context, this review paper sheds light into the emerging trends in TiO2 in terms of its modifications towards multifunctional photocatalytic applications.

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“…The ratio between LFI and HFI is the η ct,imps , which is the fraction of holes transferred successfully to the electrolyte that participates to the water oxidation (or others) reaction and is expressed as follows 132,134,135 :…”

Section: Photoelectrochemical Impedance Spectroscopy Intensity-modulmentioning

confidence: 99%

“…In a recent work, Yalavarthi et al simultaneously applied PEIS, IMPS, and IMVS and probed the electronhole recombination kinetics and hole transfer efficiency in mixed-phase TiO 2 nanotubes. 135 In another work, IMVS has been used to probe hematite photoelectrodes. 136 Also, Klotz et al compared these three PEC immittance triplets (PIT), consisting of PEIS, IMPS, and IMPS.…”

Section: Photoelectrochemical Impedance Spectroscopy Intensity-modulmentioning

confidence: 99%

In situ characterizations of photoelectrochemical cells for solar fuels and chemicals

Yalavarthi

Henrotte

Minguzzi

et al. 2020

MRS Energy & Sustainability

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Radiative and Non-Radiative Recombination Pathways in Mixed-Phase TiO2 Nanotubes for PEC Water-Splitting

Cited by 50 publications

References 75 publications

Investigating and Correlating Photoelectrochemical, Photocatalytic, and Antimicrobial Properties of TiO2 Nanolayers

Investigating and Correlating Photoelectrochemical, Photocatalytic, and Antimicrobial Properties of TiO2 Nanolayers

Insights into the TiO2-Based Photocatalytic Systems and Their Mechanisms

In situ characterizations of photoelectrochemical cells for solar fuels and chemicals

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