High-Performance Ni/Al2O3-(Zr + Ce)O2 catalysts for syngas production via ethanol dry reforming

Series of Ni/xAl(2)O(3)-(100-x)(0.88Zr + 0.12Ce)O-2 (denoted as Ni/xACZ) were prepared to elucidate the effect of Al/Zr ratio on Ni-support interaction and activity/stability in ethanol dry reforming (EDR). The change in the catalysts' physicochemical properties before and after EDR reaction was determined using various characterization techniques including X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, H-2-temperature programmed reduction, CO2-temperature programmed desorption, ferromagnetic resonance, thermogravimetric analysis and Raman spectroscopy. Increasing the Al/Zr ratio (from 5 mol.% to 75 mol.% alumina content) resulted in Ni nanoparticles' size decreasing as well as the increasing metal-support interaction (MSI). The structural properties of the Al-rich (x = 50, 75 mol.%) oxide supports provided the highest activity and stability in EDR. In contrast, the Zr-rich samples (x = 5, 20 mol. %) showed lower EDR activity and stability due to the large nickel particle size and the deactivation of Ni-0 nanoparticles with graphitized carbon. The Ni/50ACZ catalyst achieved stable and balanced H-2 and CO yields (similar to 77% each, with a CO/H-2 ratio close to 1) and exceptional C2H5OH/CO2 conversions of 100/63% at 650 degrees C, owing to nanosized Ni-0, optimal MSI, and high thermal stability.