Effect of nickel loading on the performance of Ni/MgAl2O4 catalysts for LPG steam reforming

Abstract

Ni catalysts with different loadings (10, 15 and 20 wt%) supported on MgAl2O4 were studied for Liquefied Petroleum Gas (LPG) steam reforming. In-situ X-ray diffraction (XRD) and XANES (X-ray absorption near-edge structure), analyses showed that the initial reduction temperature was related to the percentage of Ni present in the catalyst. Extended X-ray absorption fine structure (EXAFS) data indicated similar Ni-Ni interatomic distances for all the samples and very close to the simulated value found for reference of Ni0, indicating the complete reduction of the samples. MgAl2O4 supported Ni catalysts were active for LPG steam reforming at 873 K, with some deactivation after 24 h of reaction. The samples with higher Ni loadings (20Ni/MgAl2O4 and 15Ni/MgAl2O4) showed similar LPG steam reforming products, with H2 representing around 78% of the products detected in the gas phase (dry molar basis). 10Ni/MgAl2O4 was less active, although it also presented high H2 formation. Thermogravimetric analysis showed that carbon deposition was a significant factor for catalyst deactivation.