PtAu/C electrocatalysts as anodes for direct ammonia fuel cell

• Evaluation of PtAu/C catalysts by electrochemical experiments.
• Effect of PtAu/C electrocatalysts in a direct ammonia fuel cell.
• PtAu/C 70:30 showed a power density 60% higher than Pt/C.
• PtAu/C 70:30 showed alloyed phase and lower Au-N energy adsorption.

PtAu/C electrocatalysts prepared by borohydride reduction method with different Pt:Au atomic ratios (50:50 and 70:30) were tested as work electrodes/anodes in electrochemical experiments and also using a direct ammonia fuel cell (DAFC). X-ray diffraction patterns showed the formation of PtAu alloy while transmission electron micrographs showed the particles sizes between 5.8 and 6.4 nm. PtAu/C 70:30 presented the best results showing a current density about 20% higher when compared to Pt/C in voltammetry experiments and a power density about 60% higher than Pt/C using DAFC, while Au/C showed practically no activity in both experiments. The best results obtained with PtAu/C (70:30) could be explained by the electronic effect (PtAu alloy) associated with adsorbed hydroxyl species (AuOHads) and also the lower Au-N energy adsorption.

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