On the Importance of Nanoparticle Necks and Carbon Impurities for Charge Trapping in TiO2

Elser MJ, Neige E, Berger T, Chiesa M, Giamello E, Mckenna K, Risse T, Diwald O (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Journal of Physical Chemistry C American Chemical Society

DOI: 10.1021/acs.jpcc.3c00430

Abstract

Particle attachment and neck formation inside TiO2 nanoparticle networks determine materials performance in sensing, photo-electrochemistry, and catalysis. Nanoparticle necks can feature point defects with potential impact on the separation and recombination of photogenerated charges. Here, we investigated with electron paramagnetic resonance a point defect that traps electrons and predominantly forms in aggregated TiO2 nano particle systems. The associated paramagnetic center resonates in the g factor range between g = 2.0018 and 2.0028. Structure characterization and electron paramagnetic resonance data suggest that during materials processing, the paramagnetic electron center accumulates in the region of nanoparticle necks, where O2 adsorption and condensation can occur at cryogenic temperatures. Complementary density functional theory calculations reveal that residual carbon atoms, which potentially originate from synthesis, can substitute oxygen ions in the anionic sublattice, where they trap one or two electrons that mainly localize at the carbon. Their emergence upon particle neck formation is explained by the synthesis-and/or processing-induced particle attachment and aggregation facilitating carbon atom incorporation into the lattice. This study represents a substantial advance in linking dopants, point defects, and their spectroscopic fingerprints to microstructural features of oxide nanomaterials.

Involved external institutions

Universität Salzburg (Paris Lodron Universität Salzburg) AT Austria (AT) University of Turin / Università degli Studi di Torino (UNITO) IT Italy (IT) University of York GB United Kingdom (GB) Freie Universität Berlin DE Germany (DE)

How to cite

APA:

Elser, M.J., Neige, E., Berger, T., Chiesa, M., Giamello, E., Mckenna, K.,... Diwald, O. (2023). On the Importance of Nanoparticle Necks and Carbon Impurities for Charge Trapping in TiO2. Journal of Physical Chemistry C. https://dx.doi.org/10.1021/acs.jpcc.3c00430

MLA:

Elser, Michael J., et al. "On the Importance of Nanoparticle Necks and Carbon Impurities for Charge Trapping in TiO2." Journal of Physical Chemistry C (2023).

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