Effect of O2 and temperature on the catalytic performance of Ni/Al2O3 and Ni/MgAl2O4 for the dry reforming of methane (DRM)

Al2O3 and MgAl2O4 supported 10% (w/w) Ni catalysts having a dispersion of 1.5 and 2.0% are active for DRM at 600 and 750 degrees C. High temperature reduction of both the calcined catalysts resulted in metallic Ni being formed, suggesting strong support metal interactions. The CH4 and CO2 conversion during DRM are relatively constant with time-on-stream, and are higher for Ni/MgAl2O4 than Ni/Al2O3. Carbon-whiskers are also detected on both catalysts. O-2 co-feed of 2.6% (v/v) and increasing reaction temperature to 750 degrees C helped in decreasing the amount of carbon deposited, except for Ni/MgAl2O3 at 600 degrees C. Furthermore, higher conversions and H-2/CO ratios are achieved. It appears that on spent Ni/MgAl2O3 a different type of carbon species was formed, and this carbon species was difficult to remove by oxygen at 600 degrees C. Thus, co-feeding O-2, using an appropriate temperature, and choosing a suitable support can reduce the carbon present on the nickel catalysts during DRM. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.