Impact of gallium loading and process conditions on H2 production from dry reforming of methane over Ni/ZrO2-Al2O3 catalysts

Ni stabilized over zirconia-alumina support (10Ni/10ZrAl), and further enhanced with gallium promotion, was examined for its efficacy in dry reforming of methane. 1–3 wt % gallium addition to the 10Ni/10ZrAl catalyst led to an even distribution of gallium throughout the catalyst, increased formation of NiO species that are easily reduced, and deposition of less graphitic carbon compared to an unpromoted catalyst. 10Ni2Ga/10ZrAl catalyst has least carbon deposition and highest H₂ yield (26 %) at 600 ^°C. Process optimization is performed over best catalyst, 10Ni2Ga/10ZrAl, by varying space velocity from 30,000 cm³ g⁻¹h⁻¹ to 48,000 cm³g⁻¹h⁻¹, reaction temperature from 550 °C to 800 °C, and CH₄/CO₂ from 0.5 to 1. A regression model equation is set as the function of factors, and the response as H₂ yield through research surface methodology under center composite design. The model predicted an optimal H₂ yield of 91.95 % which is closely validated by 90.09 % H₂ yield experimental at optimized conditions.