Core/Shell and Hollow Metal-Oxide Nanoparticles Supported on ZSM-5: Synthesis and Properties
Current communication is devoted to study of oxidation processes of metal (Cu, Ni, Co) nanoparticles supported on ZSM-5 zeolite, aiming to find correlation between structures of metal-oxide particles, such as core/shell, hollow and bulk, and oxidation conditions. TPR-H2, XRD in situ, HRTEM, XPS with sample pretreatment in high-pressure cell, UV-Vis DR, and the optical spectra modeling were used to confirm the hypothesis about structure of metal-oxide particles. CO and NO oxidation as well as NO SCR by propane were employed to examine catalytic characteristics of different metal-oxide particles. Nanoscale Kirkendall effect was shown to be reveal at low-temperature oxidation of Cu and Ni nanoparticles and at hightemperature oxidation of Co. Hollow metal-oxide nanoparticles are formed from core/shell particles containing the 3-5 nm oxide layer on surface of 10-20 nm metal particle due to different diffusion coefficients.
The core/shell, hollow and bulk metal-oxide particles have different optical, redox and catalytic properties.