Direct ammonia fuel cell performance using PtIr/C as anode electrocatalysts

Abstract

Direct ammonia fuel cell (DAFC) performance was investigated using as anode PtIr/C electrocatalysts (Pt:Ir atomic ratios of 50:50, 70:30, 80:20 and 90:10) prepared by the borohydride reduction process and NH4OH 1.0, 3.0 and 5.0 mol L 1 in KOH 1.0 mol L 1 as fuel. Xray analyses of PtIr/C electrocatalysts suggested the formation of PtIr alloy and the transmission electron micrographs showed the average particle diameters between 4.5 and 6.0 nm. Using PtIr/C 50:50 electrocatalyst and NH4OH 5.0 mol L 1 in KOH 1.0 mol L 1 at 40 C a maximum power density was 48% and 70% higher than that obtained using Pt/C and Ir/C electrocatalysts, respectively. The increase of electroactivity using PtIr/C electrocatalysts might be related to a decrease of poisoning on catalyst surface by Nads species and to an improved kinetic for ammonia oxidation reaction.