Functionalization of Pt-doped cerium oxide films by bio- and organic molecules

The rapid progress of nanotechnology in the field of bioapplications and organic electronics brings in front the need to attach bio- or organic molecules to inorganic materials. The nanoworld implies the use of minimal quantities of molecules as well as substrates, thus the formed interface plays a crucial role in the physicochemical properties of a system. Chemical functionalization of metal oxide surfaces by covalent attachment of molecules is one of the most general strategies for the synthesis of new materials for nanotechnology.

In this work Pt-doped cerium oxide films are proposed as a complex system with excellent biocompatible, non-toxic and catalytic properties. Cerium oxide itself is an active support for catalytic metals, organic or biomolecules. Platinum plays a crucial role in many catalytic and electrocatalytic systems and also possesses a wide range of antioxidant properties. The Pt-doped CeO₂ has many potential advantages, but there is very limited data on the effect of the combined use of platinum and cerium dioxide with bio- and organic molecules. Taurine, histidine and lysine are among the possible biomolecules, that efficiently model the organic molecule with sulfonate and carboxylate linker groups. In addition, the ciliatine molecule will be considered as a molecule with a phosphonate anchor group.

The polycrystalline CeO₂ thin films will be prepared by magnetron sputtering technique. This approach will also allow us to directly dope or adsorb controlled amounts of Pt metal onto CeO₂ to form metal species ranging from dispersed single atoms or clusters adsorbed on the oxide surface to atoms incorporated into the oxide crystal lattice. The film morphology will be analysed by scanning electron microscope, transmission electron microscopy or atomic forse microscopy. We will explore the functionalization of CeO₂ with the above mentioned small model molecules that, unlike bulky polymers, allow the oxide surface to chemically interact with the surrounding environment. The molecules will be deposited in ultra-high vacuum and/or from solutions. Photoelectron-based surface science techniques, including ultra-high vacuum and near-ambient pressure X-ray photoelectron spectroscopies, will then be used to study how the molecules are bound to the oxide surface. The role of Pt in the molecular bonding to the surface will be elucidated. The main goal is the development of strategies for the surface functionalization of cerium oxide in a nanostructured form for bio and organic applications.

Literature

1. Surface Analysis by Auger and X-Ray Photoelectron Spectroscopy, D. Briggs, J. T. Grant, IMPublications, Chichester, UK and SurfaceSpectra, Manchester, UK, 2003, ISBN: 1‐901019‐04‐7.
2. Catalysis by Ceria and Related Materials, A. Trovarelli, Imperial College Press, London, UK, 2002, ISBN: 978-1-86094-299-0.
3. P. Pujari, et al., Angew. Chem. Int. Ed. 53 (2014) 6322, DOI: 10.1002/anie.201306709
4. Tsud et al., Phys. Chem. Chem. Phys. 17 (2015) 2770, DOI: 10.1039/c4cp03780d
5. Matolin et al., Langmuir 26 (2010) 12824, DOI: 10.1021/la100399t
6. Fan et al., ACS Nano 15 (2021) 2005, DOI: 10.1021/acsnano.0c06962
7. Ma et al., ACS Sustainable Chem. Eng. 11 (2023) 6163, DOI: 10.1021/acssuschemeng.2c06682
8. S. Lord et al., Small 17 (2021) 2102342, DOI: 10.1002/smll.202102342
9. Moglianetti et al., Nanoscale 8 (2016) 3739, DOI: 10.1039/c5nr08358c
10. Lykhach et al., Catal. Sci. Technol., 7 (2017) 4315, DOI: 10.1039/c7cy00710h