Positron Lifetime And Magnetization Studies Of Rare Earth Oxides As Desulfurization Adsorbents
Rare Earth Oxide (REOs) nanoparticle catalysts are used as Desulfurization Adsorbents. The nanoporosity of
these catalysts may influence the diffusion characteristics that may affect the desulfurization absorption efficiencies. Positron
annihilation lifetime spectrometer (PALS) is used to study the nanoporosity of metal oxide nanoparticle catalyst powders.
Rare Earth Oxide (REOs) nanoparticle catalysts with Mn, Al, Ce, La, Fe, and Gd metal compositions were prepared using
Evaporation Induced Self Assembly and Sol-gel methods to prepare catalyst granules followed by calcination and
co-impregnation with Mn or Al. Different composition samples were examined by PALS before and after reaction, and after
desulfurization. The positronium lifetime component provides the information on pore size (lifetimes) and concentration of
pores (intensities). Al rich catalysts have larger nanopores with lesser concentration and higher fractional free volume (1.5 to
2 times) compared to all other REO catalysts without Al. The pore concentration has increased after catalytic reaction
resulting in an increase in fractional free volume. This could be due to low oxygen content observed in post reaction samples
as some of the oxides might have reduced to metals during the reaction and forming new pores. Magne.
Index Terms—Desulfurization, Magnetization, Nano-porosity. Positron lifetime, Rare earth catalysts.