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 → 2H2 + 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 CO2gas, 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 CH4and CO2. The catalytic performance of the limonite ore was inferior to the Ni/Al2O3catalyst 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.