A Surface Study of Ultrathin Ceria Nanoparticles Decorated with Transition‐Metal Ions

Abstract

A wide range of nanoparticle properties can be tuned by changing their surface characteristics, especially when dealing with ultrathin nanomaterials. Surface modification with transition‐metal ions may affect a variety of the nanoparticles' properties including the surface charge, the electronic structure, and the electrical and optical characteristics. In this work, a surface study of ceria nanoparticles modified by attachment of various transition‐metal ions to their surface is conducted. Characterization of the decorated particles as well as of the modifying transition‐metal ion is carried out using zeta potential in organic solution, UV–Vis absorption, and electron paramagnetic resonance measurements, together with isothermal titration calorimetry, X‐ray photoelectron spectroscopy, and energy dispersive X‐ray spectroscopy. All measurements confirm the attachment of the cation to the surface of ceria, both in solid state and in colloidal suspension. It is suggested that the modifying ion‐complex attaches to ceria both via chemical or strong physical interactions and weak physical interactions, demonstrated by a case‐study modification of ceria using a copper‐oleylamine complex. The metalization has a significant effect on the surface charge of the nanoparticles by shifting the zeta potential to more positive values and on the optical properties of the modifying transition‐metal ions by red‐shifting their absorption peak.

Metal/semiconductor interfaces in nanoscale objects: synthesis, emerging properties and applications of hybrid nanostructures

“…We refer the reader to a review by Dubertret and co-workers on 2D colloidal nanocrystals. 192 Other classes of interfaces receiving tremendous attention in recent years mainly due to their promising catalytic abilities are metal-containing molecular species, [193][194][195][196] hydrogenase enzymes, 197 metal-organic frameworks (MOFs), 198 and even metal-encapsulated MOFs. [199][200][201][202][203] Since their attachment to the SC is usually chemisorption or some physical interaction (electrostatic), they are out of the scope of this review.…”