Basic oxides such as alkali metal oxides, alkaline earth metal oxides, and rare earth oxides were added to Ru/Pr6O11, and the activity of the catalysts with respect to hydrogen production by ammonia decomposition was investigated. Ru/Pr6O11 doped with alkali metal oxides, except for Li2O, achieved higher NH3 conversions than bare Ru/Pr6O11 center dot Cs2O, the most basic of the alkali metal oxides, was the most effective dopant. In contrast, other dopants with lower basicity than the alkali metal oxides achieved lower NH3 conversions than bare Ru/Pr6O11. Changing the Cs/Ru molar ratio revealed that the best Cs/Ru ratio was 0.5-2; the reaction was effectively promoted without negative effects from coverage of the Ru surface by the Cs2O. Varying the order of loading the Ru and Cs2O onto Pr6O11 revealed that loading Ru onto Cs2O/Pr6O11 was an effective way to enhance NH3 conversion, and coverage of the Ru surface was reduced. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.