SnO2-modified Pt electrocatalysts for ammonia–fueled anion exchange membrane fuel cells

•The ammonia oxidation over SnO2–modified Pt catalysts was evaluated in alkaline media.•SnO2 activated the dehydrogenation reaction of ammonia over Pt.•SnO2 was stable under 1000 potential cycles (0.05–0.9 V vs. RHE) in alkaline media.

The electrochemical oxidation of ammonia over two types of SnO2-modified Pt (C–Pt/SnO2, SnO2–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 NH3. The ammonia oxidation current achieved during the LSVs was in the order C–Pt/SnO2 > SnO2–Pt/C > Pt/C. In addition, the apparent activation energies for ammonia oxidation calculated from the CAs for C–Pt/SnO2, SnO2–Pt/C, and Pt/C at various temperatures were 52, 58, and 67 kJ mol−1, respectively. These results indicated that SnO2 activated the dehydrogenation of ammonia over Pt. Moreover, the I–V characteristics of an ammonia-fueled anion exchange membrane fuel cell with the SnO2–Pt/C anode clearly achieved a higher performance than with the Pt/C anode.