Room temperature synthesis of UO2+x nanocrystals and thin films via hydrolysis of uranium(iv) complexes

• Published in: Inorganic chemistry frontiers 2022-02, Vol.9 (4), p.678-685
• Main Authors: Murillo, Jesse, Panda, Debiprasad, Chakrabarti, Subhananda, Hattori, Alex, Griego, Leonel, Chava, Venkata S N, Sreenivasan, Sreeprasad T, Ramana, Chintalapalle V, tier, Skye
• Format: Article
• Language: English
• Subjects: Fast Fourier transformations; Fluorite; Fourier transforms; Glass substrates; High resolution electron microscopy; Hydrolysis; Inorganic chemistry; Nanocrystals; Nanoparticles; Raman spectroscopy; Room temperature; Silicon substrates; Thin films; Uranium; Uranium compounds; Uranium dioxide; X ray powder diffraction
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/d1qi01248g

Methods for the straightforward, room temperature synthesis of UO2+x nanoparticles and thin films using solution processable, molecular uranium(iv) compounds is described. Ultra-small uranium dioxide nanoparticles are synthesized from the hydrolysis of either U(ditox)4 (ditox = −OCHtBu2) (1) or U(CH2SiMe2NSiMe3)[N(SiMe3)2]2 (2) via addition of water to stirring solutions of the compounds in non-polar solvents to give UO2-1 and UO2-2, respectively. The structural characteristics of the uranium dioxide nanoparticles were characterized using powder X-ray diffraction (pXRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. The pXRD results affirm the cubic fluorite structure expected for UO2 nanoparticles. The nanocrystallinity of UO2-1 and UO2-2 were substantiated by bright-field HRTEM images and fast Fourier transform (FFT) patterns. The HRTEM analysis also shows the nanoparticles fall within the ultra-small regime possessing sizes of ∼3 nm with uniform distribution. Additionally, we demonstrate the versatility of 1 as a uranium dioxide precursor, showing that it can be readily sublimed onto glass or silicon substrates and subsequently hydrolyzed to give UO2+x thin films.