Effect of MgO/Al2O3 ratio in the support of mesoporous Ni/MgO–Al2O3 catalysts for CO2 utilization via reverse water gas shift reaction

Abstract

2 and 5 wt.% nickel was supported on different MgO to Al₂O₃ (M/A) ratios (0.5, 1 and 1.5) and evaluated in reverse water gas shift (RWGS) reaction. The catalysts were prepared by impregnation method and the nanocrystalline supports were synthesized by simple surfactant (CTAB) assisted precipitation technique. The following catalytic activity was observed for 2% & 5% Ni supported on different M/A ratios; M/A = 1 > M/A = 1.5 > M/A = 0.5. The perceived order was related to difference in the structural properties of supports and catalysts. The BET results revealed decrease of specific surface area with increase in M/A ratio, mesoporous structure for M/A = 0.5 and 1 and meso-macroporous structure for M/A = 1.5. The effect of nickel loading on the support with M/A = 1 was also investigated. 1.5% Ni showed high CO₂ conversion of 39.2% at 700 °C and CO selectivity higher than 90% at all temperatures. Increase of …