Impregnation vs. sol-gel and sol-gel-plasma dispersion of nickel nanoparticles over Al2O3 employed in combined dry reforming and partial oxidation of greenhouse gases to syngas

Abstract

This paper is focused on the fabrication of Ni/Al2O3 nanocatalyst via impregnation, sol-gel and hybrid sol-gel plasma techniques. Physiochemical properties of the samples were characterized by XRD, FESEM, TEM, EDX, BET and FTIR analyses. Also, used nanocatalysts were characterized via TG-DTG, FESEM, EDX and XRD analyses. The catalytic performance of the nanocatalysts was investigated. XRD patterns proved that for sol-gel based samples, amorphous behaviour was intensified and concentration of prone planes to coke deposition was decreased especially in plasma treated one. FESEM images were exhibited that homogenous particle size distribution was obtained for the sample which prepared by sol-gel-plasma method. TEM and EDX analyses reported the promoted nickel dispersion for sol-gel based samples especially in plasma treated sample. Owing to the BET results utmost surface area 297 m2/g was declared for sol-gel-plasma catalyst. Sol-gel-plasma catalyst indicated the higher catalytic activity compared to the others. In addition, conducted stability test during 2880 min asserted that, deactivation was occurred in all samples but sol-gel-plasma catalyst is more stable. After stability test, sol-gel-plasma catalyst roughly preserved its structure while active phase migration was took place for the others. Also, based on EDX and TG-DTG results, more uniform dispersion and lowest amount of coke deposit was found for sol-gel-plasma catalyst.