Tri-reforming of CH4 over a Thermally Stable and Carbon-Resistant Nanonickel Metal Catalyst Dispersed on Mesoporous-Zirconia

A novel nanonickel metal catalyst dispersed on mesoporous-zirconia is developed for the controlled production of the synthesis gas with an H2/CO molar ratio of 1.5–2 via the tri-reforming of methane (TRM). The catalysts were tested in a fixed-bed reactor at 600–850 °C and 1 atm. At the optimum feed (CH4/CO2/O2/H2O/N2) ratio of 1:0.5:0.1:0.0125:1, the maximum CO2 and CH4 conversion was ∼28 and ∼86%, respectively, over the 5 wt % Ni/ZrO2. At this condition, the syngas with an H2/CO ratio of ∼1.5 was achieved at a lower reaction temperature of 700 °C. The superior activity of this catalyst was due to the presence of highly dispersed and reduced nickel particles over the combined tetragonal and monoclinic phases of mesoporous ZrO2. The basic strength of the catalyst, the nickel particle size, and metal dispersion played vital roles in controlling the TRM activity as well as the H2/CO ratio. The time-on-stream study and the used catalyst characterization results established that the nanosized nickel metal particles dispersed on mesoporous zirconia were thermally stable and coke-resistant.