A B S T R A C TThe electrochemical oxidation of ammonia over two types of SnO 2 -modified Pt (C-Pt/SnO 2 , SnO 2 -Pt/C) and Pt/C electrocatalysts was evaluated in alkaline aqueous solutions. Linear sweep voltammograms (LSVs) and chronoamperograms (CAs) were obtained in a 1 M KOH solution with 0.1 M NH 3 . The ammonia oxidation current achieved during the LSVs was in the order C-Pt/SnO 2 > SnO 2 -Pt/C > Pt/C. In addition, the apparent activation energies for ammonia oxidation calculated from the CAs for C-Pt/SnO 2 , SnO 2 -Pt/ C, and Pt/C at various temperatures were 52, 58, and 67 kJ mol À1 , respectively. These results indicated that SnO 2 activated the dehydrogenation of ammonia over Pt. Moreover, the I-V characteristics of an ammonia-fueled anion exchange membrane fuel cell with the SnO 2 -Pt/C anode clearly achieved a higher performance than with the Pt/C anode.