Monodisperse Samarium and Cerium Orthovanadate Nanocrystals and Metal Oxidation States on the Nanocrystal Surface

Abstract

A new solvothermal method has been developed for the synthesis of monodisperse SmVO4 and CeVO4 nanocrystals with controlled size and shape. The obtained materials were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) techniques. The results reveal that uniform nanocrystals and pure tetragonal phase of SmVO4 and CeVO4 can be achieved. To investigate the oxidation states of the metals on the mixed oxide nanocrystal surface, the XPS technique was employed. The results exhibit that only one oxidation state of samarium, cerium, and vanadium for each metal (e.g., Sm3+, Ce3+, V5+) was surprisingly well stable on the particle surface at the nanoscale, even after calcination, while the existence of two oxidation states of these metals is observed (e.g., Sm3+/Sm2+, Ce4+/Ce3+, V5+/V4+) in the corresponding single metal oxide nanocrystals.

Solvothermal Synthesis of Yolk–Shell CeVO4/C Microspheres as a High‐Performance Anode for Lithium‐Ion Batteries

“…The main peaks at 881.3 and 885.5 eV are assigned to the Ce 3d 5/2 binding energy, whereas the peaks centered at 899.9 and 904.1 eV are ascribed to the Ce 3d 3/2 binding energy. These binding energy values are close to the reported value of Ce 3+ and no peak corresponding to Ce 4+ is observed . The peaks at binding energies of 516.8 and 524.6 eV correspond to V 2p 3/2 and V 2p 1/2 , respectively, in accordance with V 5+ (Figure c) .…”

CeVO4 Nanozymes Catalyze the Reduction of Dioxygen to Water without Releasing Partially Reduced Oxygen Species

“…The phase of the nanoparticles was further confirmed by Raman and Fourier transform infrared (FT‐IR) spectroscopy (Figure S3b and S4) ,. The UV/Vis spectra show a broad band in the region of 275 nm, which can be attributed to the charge transfer from oxygen ligands to central vanadium atom of VO 4 3− ions (Figure S5) . The X‐ray photoelectron spectroscopy (XPS) revealed the presence of mixed oxidation state of cerium that is, +3 and +4 (Figure S6 a,d,g) and higher Ce 3+ /Ce 4+ ratio for Cs as compared to that of Csc and Ch.…”

Photochemical synthesis and characterization of novel samarium oxide nanoparticles: toward a heterogeneous Brønsted acid catalyst

“…This was evident from the presence of a doublet that dominated the 1050.0-1150.0 eV region of the XPS survey of the material (Fig. 11,13,17,21 Samarium is redox active, so it is possible that the material may respond to its chemical environment by alternating between Sm 2 O 3 and SmO to some extent. Peak splitting is well known to be the result of j-j coupling, which in this case gave rise to two intense peaks centred at 1084.0 and 1110.3 eV.…”