Highly efficient Ru/MgO-Er2O3 catalysts for ammonia synthesis

This study aimed to develop a highly efficient Ru catalyst using mixed oxide support of lanthanides and MgO. Mixed oxide support of Er2O3 with MgO showed higher catalytic activity for ammonia synthesis among other lanthanides. Therefore, MgO-Er2O3 mixed oxide supports with different molar ratios of Mg/Er were prepared by the co-precipitation method. 1% Ru was deposited by the impregnation method using Ru(NO3)(3) as a Ru precursor. The activity measurement for ammonia synthesis was carried out in a fixed-bed flow reactor. It was found that the catalytic activity of the Ru/MgO-Er2O3 catalyst with higher MgO content (Mg/Er = 25/1) was comparably high as that obtained for 1% Ru deposited on pure Er2O3 support under same reaction conditions. The plausible reason was attributed to the same textural properties of the mixed oxide MgO-Er2O3 supported Ru catalysts up to a Mg/Er ratio of 25/1, where Ru was selectively deposited on Er2O3.