Facile Room-Temperature Synthesis of Cerium Carbonate and Cerium Oxide Nano- and Microparticles Using 1,1′-Carbonyldiimidazole and Imidazole in a Nonaqueous Solvent

Abstract

Ceria nanoparticles (CeONPs) are versatile materials due to their unique catalytic properties, and cerium carbonate particles (CeCbPs) have been widely used as precursors for cerium oxide due to their ease of production. Urea is a widely used precipitant and a source of carbonate ions for the synthesis of CeONPs and CeCbPs, and the reaction temperature is important for controlling the rate of urea decomposition. However, the precise control of the temperature is often difficult, especially in large-scale reactions. Herein, we propose a homogeneous precipitation method that uses 1,1′-carbonyldiimidazole (CDI) and imidazole in acetone without heating. The decomposition rate of CDI can be controlled by the amount of water in the reaction mixture. In the synthesis of CeCbPs, unique particle morphologies of plate-, flying-saucer-, and macaron-like shapes and a wide range of sizes from 180 nm to 13 μm can be achieved by adjusting the amount of CDI, imidazole, and water in the reaction. These CeCbPs are transformed into ceria particles by calcination while maintaining their characteristic morphology. Moreover, the direct synthesis of 130 nm spherical CeONPs was possible by decreasing the amount of CDI in the reaction and the mixing time. These nanoparticles exhibited higher production efficiency and superior reactive oxygen species (ROS) scavenging properties compared to the other CeONPs obtained from calcination. These results demonstrate a novel method using CDI and imidazole in the synthesis of CeONPs and CeCbPs without the aid of a heating process, which may be useful in the large-scale synthesis and application of CeO nanomaterials.

Biocompatible Cerium Carbonate-Based Nanozymes for Oxidase Activity, Sensing, Computed Tomography Contrast, and Delivery of Small Molecules

“…To further confirm the phase composition of synthesized Ce 2 (CO 3 ) 2 O·H 2 O NPs, we have carried out an X-ray diffraction (XRD) analysis. As shown in Figure B, XRD patterns with typical peaks corresponding to the (110), (111), (102), (131), and (221) facets at 20.6, 23.9, 30.3, 38.4, and 43.7°, respectively, reveal that the NPs are cerium oxycarbonate (Ce 2 (CO 3 ) 2 O·H 2 O), well matched with the JCPDS#44-0617 . Subsequently, Brunauer–Emmett–Teller (BET) surface area and pore size distribution of Ce 2 (CO 3 ) 2 O·H 2 O NPs are investigated by using nitrogen gas adsorption.…”

“…We have synthesized Ce 2 (CO 3 ) 2 O·H 2 O NPs via the precipitation method by following a previously reported protocol . Briefly, Ce 2 (CO 3 ) 2 O·H 2 O NPs were fabricated by a simple precipitation method by mixing cerium nitrate hexahydrate (Ce­(NO 3 ) 3 ·6 H 2 O), 1,1′-carbonyldiimidazole (CDI), and imidazole as a starting reactant.…”

Selective Recovery of Cerium as High-Purity Oxides via Reactive Separation Using CO2-Responsive Structured Ligands

“…91,92 This industrially relevant compound can be prepared easily via the calcination of cerium carbonates. 85 This suggests that access to high-purity CeO 2 that is sufficiently pure for downstream applications can be synthesized by using our approach without arduous liquid− liquid extraction and purification steps. Under calcination conditions, smooth conversion to CeO 2 was observed over the course of 2 h. Distinct features in the ATR-IR and P-XRD spectra were found to evolve after the reaction (Figure 6B,D), and the XPS spectrum displayed new peaks distinctly associated with Ce(IV) that were previously absent (Figure 7C and Figures S20−S22).…”

Mesoporous Cerium Oxide Nanoparticles with High Scavenging Properties of Reactive Oxygen Species for Treating Age‐Related Macular Degeneration

“…In Vitro ROS-Scavenging Properties of mCeNPs: To evaluate the catalaseand SOD-mimicking activities of mCeNPs, the Amplex red hydrogen peroxide/peroxidase assay and SOD determination assay were performed using a previously reported method, with slight modifications. [55] For assessing the catalase-mimicking activities of mCeNPs, a 100 μM H 2 O 2 solution was added to each well of a 24-well plate, followed by the addition of mCeNPs (0, 10, 25, 50, and 100 μg mL À1 ), and reacted for 1 h. For assessing the SOD-mimicking activities, mCeNPs (0, 50, and 100 μg mL À1 ) were added to WST-1 working solution (2-(4-iodophenyl)-3-(4-nitro-phenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) in 1.5 mL microcentrifuge tubes, and after reacting for 20 min, the supernatants were transferred to 96-well plates after centrifugation to measure the absorbance. The measurements were conducted four times for the Amplex red hydrogen peroxide/peroxidase assay and three times for the SOD determination assay.…”