Effects of hydrothermal etching and conversion on photocatalytic hydrogen evolution and overall water splitting with nanoparticulate and mesoporous TiO₂ and SrTiO₃/TiO₂ composites

Titelangaben

Schumacher, Lion ; Timm, Jana ; Marschall, Roland:
Effects of hydrothermal etching and conversion on photocatalytic hydrogen evolution and overall water splitting with nanoparticulate and mesoporous TiO₂ and SrTiO₃/TiO₂ composites.
In: Journal of Materials Chemistry A. Bd. 12 (2024) . - S. 30768-30782.
ISSN 2050-7496
DOI: https://doi.org/10.1039/D4TA03416C

Volltext

Link zum Volltext (externe URL):

Abstract

TiO2 and SrTiO3 are well-studied semiconductors for photocatalytic H2 evolution and overall water splitting, respectively. Hydrothermal conversion of different TiO2 starting materials enables the synthesis of SrTiO3/TiO2 composites with various morphological designs, which have so far shown increases in photocatalytic H2 evolution activity. Herein, we address this phenomenon and the underlying influences of alkaline and pH-neutral media during hydrothermal conversion reactions by detailed material characterization of SrTiO3/TiO2 composites and etched TiO2. Trends in photocatalytic H2 evolution activities can be related directly to morphological factors, which in turn determine the influence of hydrothermal treatment. TiO2 nanoparticles are mainly subjected to agglomeration, while mesoporous TiO2 benefits from increasing hydrophilicity and a broadening of pore size distributions. Taken together, both influences lead to “pore activation” that strongly enhances photocatalytic H2 evolution activities. Simple hydrothermal treatment in diluted NaOH solution or even plain H2O might be a promising strategy to enhance photocatalytic activities of mesoporous TiO2 and potentially other mesoporous semiconductors, but more importantly, it also needs to be taken into account in the case of hydrothermal conversion reactions, since the subtle impact of the reaction medium may be overlooked or misinterpreted as a composite effect.