In-Situ Synchrotron Radiation Study of Formation and Growth of Crystalline CexZr1-xO2 Nanoparticles Synthesized in Supercritical Water

Summary, in English

In situ synchrotron powder X-ray diffraction (PXRD) measurements have been conducted to follow the nucleation and growth of crystalline CexZr1-xO2 nanoparticles synthesized in supercritical water with a full substitution variation (x = 0, 0.2, 0.5, 0.8, and 1.0). Direction-dependent growth curves are determined and described using reaction kinetic models. A disctinct change in growth kinetics is observed with increasing cerium content. For x = 0.8 and 1.0 (high cerium content), the growth in initially limited by the surface reaction kinetics, however, at a size of similar to 6 nm, the growth changes and becomes limited by the diffusion of monomers toward the surface. For x = 0 and 0.2, the opposite behavior is observed with the growth initially being limited by diffusion (up to similar to 3.5 nm) and later by the surface reaction kinetics. Thus, although a continuous solid solution can be obtained for the ceria-zirconia system, the growth of ceria and zirconia nanoparticles is fundamentally different under supercritical flow reactor. The resulting samples were analyzed using PXRD, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). The nanoparticles with x = 0, 0.2, and 0.5 have very low polydispersities. The sizes range from 4 nm to 7 nm, and the particles exhibit a reversibly pH-dependent agglomeration.

• Author: Christoffer Tyrsted; Jacob Becker; Peter Hald; Martin Bremholm; Jan Skov Pedersen; Jacques Chevallier; Yngve Cerenius; Steen B. Iversen; Bo B. Iversen
• Department/s: MAX IV Laboratory
• Publishing year: 2010
• Language: English
• Pages: 1814-1820
• Publication/Series: Chemistry of Materials
• Volume: 22
• Issue: 5
• Links: http://dx.doi.org/10.1021/cm903316s
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Materials Chemistry
• Status: Published
• ISBN/ISSN/Other: ISSN: 0897-4756