Open AccessPhase composition, morphology, properties and improved catalytic activity of hydrothermally-derived manganese-doped ceria nanoparticles
Author(s) -
Stanislav Kurajica,
Ivana Katarina Ivković,
Goran Dražić,
Vasyl Shvalya,
Marina Duplančić,
Gordana Matijašić,
Uroš Cvelbar,
Katarina Mužina
Publication year - 2022
Publication title -
nanotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.926
H-Index - 203
eISSN - 1361-6528
pISSN - 0957-4484
DOI - 10.1088/1361-6528/ac44ed
Subject(s) - x ray photoelectron spectroscopy , materials science , nanocrystalline material , manganese , nanoparticle , high resolution transmission electron microscopy , doping , transmission electron microscopy , lattice constant , analytical chemistry (journal) , chemical engineering , nanotechnology , diffraction , chemistry , metallurgy , physics , optoelectronics , optics , chromatography , engineering
Manganese-doped ceria nanoparticles were prepared by hydrothermal synthesis and the prepared samples were thermally treated at 500 °C for 2 h. The samples were investigated using x-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectroscopy (EDS), N 2 adsorption and x-ray photoelectron spectroscopy (XPS). XRD revealed that nanocrystalline ceria is the main phase in all samples, while a romanechite-like phase (Na 2 Mn 5 O 10 ) appears in the sample doped with 30% of Mn. TEM coupled with EDS exposed the presence of the same phase in the sample doped with 20% Mn. While ceria particles have spherical morphology and particle size ranging from 4.3 to 9.2 nm, the rare crystals of the romanechite-like phase adopt a tubular morphology with a length of at least 1 μ m. However, the decrease in the ceria lattice constant and the EDS spectra of the ceria nanoparticles clearly indicate that a substantial amount of manganese entered the ceria crystal lattice. Manganese doping has a beneficial impact on the specific surface area of ceria. XPS measurements reveal a decrease in the Ce 3+ /Ce 3+ + Ce 4+ content in the doped samples which is replaced by Mn 3+ . Moreover, a drastic increase in adsorbed oxygen is observed in the doped samples which is the consequence of the increase in Mn 3+ species that promotes oxygen migrations to the surface of the sample. Compared to the pure sample, the doped samples showed significantly higher catalytic activity for the process of toluene oxidation.