Surfactant-assisted formation of organophilic CeO2 nanoparticles

Abstract

a b s t r a c tWe report a simple one-pot method to prepare organically functionalized CeO 2 nanoparticles by controlled chemical precipitation. The particles were nucleated by mixing aqueous solutions of Ce(NO 3 ) 3 ·6H 2 O and ammonia at room temperature. Different small organic molecules were chosen as capping agents and injected into the reaction medium at the beginning of the synthesis: 3-(mercaptopropyl) trimethoxy silane (MPS), hexadecyltrimethyl ammonium bromide (CTAB), 3-mercapto propionic acid (3-MPA), and thioglycolic acid (TGA). The resulting nanocrystals were quasi-spherical and had a narrow mean size distribution with an average size smaller than 10 nm. Dynamic nuclear polarization enhanced NMR (DNP-NMR) and FTIR measurements suggested a chemical grafting of the surfactant and a homogeneous surface modification. The colloidal stabilities were characterized by dynamic light scattering and zeta potential measurements. The stabilization by aliphatic groups was tested with a frequently used hydrophobic monomer, methyl methacrylate. According to the results, CTAB is the most effective of the used stabilizing surfactant. The mechanism of formation of the organophilic CeO 2 nanoparticles is discussed.

Role of Silver Nanoclusters in the Enhanced Photocatalytic Activity of Cerium Oxide Nanoparticles

“…Now, comparing the size of the CeO 2 NPs determined by XRD and TEM, it is evident that there is a difference in size calculated by the two techniques. Analogous observations have been reported previously . The discrepancy can be explained on the basis of the operational principles of TEM and XRD.…”

A review of current coupling agents for modification of metal oxide nanoparticles

“…The surface of the NPs was first coated with 3-aminopropyltrimethoxysilane (APTES) by a silanization reaction and then linked with dicarboxylic polyethyleneglycol (DCPEG) of different molecular weight (Mw = 5000, 10,000 and 20,000 gmol −1 ). Tunusoglu et al [60] prepared organically functionalized CeO 2 NPs by controlled chemical precipitation. 3-(mercaptopropyl) trimethoxy silane (MPS), hexadecyltrimethyl ammonium bromide (CTAB), 3-mercapto propionic acid (3-MPA), and thioglycolic acid (TGA) were used as coupling agents and injected into the reaction medium at the beginning of the synthesis.…”

Recent developments in MAS DNP-NMR of materials

“…DNP has been applied to characterize the surface of nanoparticles used for catalysis [124,184,192,238,268], biomaterials [106,107], cements [269], polymer fillers [85,210] and optoelectronics devices [158,159]. The investigated nanoparticles included functionalized silica [193,227,238,270], alumina [80,124,184,196,225,231,[271][272][273], silica alumina [192,233,234,274], ceria [195,275], sulfated zirconia [276], calcium silicate hydrates [269], phosphates [106,107,210], partially oxidized Sn nanoparticles [151] and crystalline semiconductors, such as CdSe, CdS or InP, in the form of nanoparticles (also called quantum dots) [158,159]. DNP has also been applied to investigate calcium silicate hydrates [269] and crystalline semiconductors, such as CdSe and CdS, in the form of nanosheets (also called nanoplatelets) (see Figure 24) [159].…”