Deactivation of SrTiO3 slurry and model photocatalysts during overall water splitting: Impact of Sr leaching on stability
4 affiliations
- 1Department of Chemical Engineering, University of Twente, P.O. Box 217,7500, Enschede, Netherlands
- 2Department of Science and High Technology, University of Insubria, Via Valleggio 11, Como, Italy, 22100
- 3Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IET-2, Cauerstraβe 1, Erlangen, Germany, 91058
- 4Dipartimento di Chimica, Università degli Studi di Pavia, Via Taramelli 16, Pavia, Italy, 27100
Abstract
Photocatalytic hydrogen evolution has been investigated for over five decades as a potential route to sustainable hydrogen production. SrTiO 3 (STO) is a benchmark photocatalyst because its band-edge positions enable overall water splitting. However, rapid charge-carrier recombination and sluggish interfacial redox kinetics limit light-to-product conversion efficiency, requiring suitable reduction and oxidation cocatalysts. While extensive research has addressed the activity and stability of cocatalysts, the stability of STO itself under reaction conditions has received less attention. Here, we investigate the deactivation of Pt-modified STO slurry and model photocatalysts during overall water splitting under UV illumination. Pt was used as stable hydrogen-evolution cocatalyst while the oxygen-evolution cocatalyst was deliberately omitted to assess how hole transfer affects photocatalyst stability. Both slurry and model photocatalysts exhibit pronounced activity decay within tens of minutes under irradiation at 365 nm and 20 mW cm -2 . STO single crystals modified with dewetted Pt nanoparticles were used as a model photocatalyst and characterized by ex situ and in situ X-ray absorption spectroscopy and inductively coupled plasma mass spectrometry, and by scanning electron microscopy, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy. The results show that photoinduced Sr leaching into the aqueous phase contributes substantially to photocatalyst deactivation. We propose that, in the absence of oxygen-evolution cocatalyst and hole scavenger, sluggish hole transfer at the STO/liquid interface initially favors lattice-oxygen oxidation and O 2 evolution, thereby destabilizing the SrTiO 3 surface and promoting Sr dissolution. Whereas STO regions covered by Pt nanoparticles remain compositionally unchanged (and enable electron transfer for Pt-mediated H 2 generation), exposed STO regions become Sr-depleted due to Sr leaching under UV irradiation and transform into a Ti-rich, TiO 2 -like surface phase. Unfavorable band alignment between bulk and Sr-depleted STO together with a high defect density within the Sr-depleted STO surface phase are proposed as main cause for charge recombination, hindering interfacial hole transfer, which ultimately suppresses photocatalytic activity.
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BibTeX
@misc{abudukade2026deactivation,
title = {{Deactivation of SrTiO3 slurry and model photocatalysts during overall water splitting: Impact of Sr leaching on stability}},
author = {MemetTursun Abudukade and Davide Spanu and Joanna Przybysz and Serhiy Cherevko and Sandro Recchia and Paolo Ghigna and Guido Mul and Marco Altomare},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010482/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010482/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Deactivation of SrTiO3 slurry and model photocatalysts during overall water splitting: Impact of Sr leaching on stability
AU - MemetTursun Abudukade
AU - Davide Spanu
AU - Joanna Przybysz
AU - Serhiy Cherevko
AU - Sandro Recchia
AU - Paolo Ghigna
AU - Guido Mul
AU - Marco Altomare
PY - 2026
DA - 2026/10/14
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010482/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010482/v1
AB - Photocatalytic hydrogen evolution has been investigated for over five decades as a potential route to sustainable hydrogen production. SrTiO 3 (STO) is a benchmark photocatalyst because its band-edge positions enable overall water splitting. However, rapid charge-carrier recombination and sluggish interfacial redox kinetics limit light-to-product conversion efficiency, requiring suitable reduction and oxidation cocatalysts. While extensive research has addressed the activity and stability of cocatalysts, the stability of STO itself under reaction conditions has received less attention. Here, we investigate the deactivation of Pt-modified STO slurry and model photocatalysts during overall water splitting under UV illumination. Pt was used as stable hydrogen-evolution cocatalyst while the oxygen-evolution cocatalyst was deliberately omitted to assess how hole transfer affects photocatalyst stability. Both slurry and model photocatalysts exhibit pronounced activity decay within tens of minutes under irradiation at 365 nm and 20 mW cm -2 . STO single crystals modified with dewetted Pt nanoparticles were used as a model photocatalyst and characterized by ex situ and in situ X-ray absorption spectroscopy and inductively coupled plasma mass spectrometry, and by scanning electron microscopy, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy. The results show that photoinduced Sr leaching into the aqueous phase contributes substantially to photocatalyst deactivation. We propose that, in the absence of oxygen-evolution cocatalyst and hole scavenger, sluggish hole transfer at the STO/liquid interface initially favors lattice-oxygen oxidation and O 2 evolution, thereby destabilizing the SrTiO 3 surface and promoting Sr dissolution. Whereas STO regions covered by Pt nanoparticles remain compositionally unchanged (and enable electron transfer for Pt-mediated H 2 generation), exposed STO regions become Sr-depleted due to Sr leaching under UV irradiation and transform into a Ti-rich, TiO 2 -like surface phase. Unfavorable band alignment between bulk and Sr-depleted STO together with a high defect density within the Sr-depleted STO surface phase are proposed as main cause for charge recombination, hindering interfacial hole transfer, which ultimately suppresses photocatalytic activity.
ER -