Effects of reduction on the catalytic performance of limonite ore

The catalytic performance of Ni-containing limonite ore in the dry reforming reaction of methane (CH4 + CO2 -> 2H(2) + 2CO) was determined before and after hydrogen reduction, and under a flow of hydrogen. After hydrogen reduction, the limonite ore exhibited higher catalytic performance, because of the formation of Fe-Ni. However, the Fe in Fe-Ni was readily oxidized by the input CO2 gas, resulting in a rapid decrease in the catalytic performance of limonite ore. The performance decrease was due to a decrease in the Ni surface area; Ni could not dissolve in iron oxides and this caused segregation in the iron oxides. When the reaction was conducted under a hydrogen flow, the Fe-Ni was formed and maintained. Ni was highly dispersed in the Fe-Ni phase, resulting in greater surface area of Ni and higher conversion rate of CH4 and CO2. The catalytic performance of the limonite ore was inferior to the Ni/Al2O3 catalyst because the effect of catalyst support was small, however, the limonite ore was more stable during catalytic use and much cheaper than the Ni/Al2O3. (c) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.