Enhancing the performance of direct urea fuel cells using Co dendrites

Mesoporous Co dendrites prepared by electroplating have a surface area of 145 m2g? 1, which is three times that of Co nanoparticles. The Co dendrites demonstrate superior urea oxidation activity compared to Ni or Co nanoparticles prepared using chemical reduction. The onset potential with Co dendrites is around 0 V ?vs. Ag/ AgCl? using 2 M urea, that is remarkably lower than 0.35 V ?vs. Ag/AgCl? for Ni catalyst at optimum urea concentration of 0.5 M. The current produced in case of the Co dendrites using 2 M urea at 0.5 V ?vs. Ag/AgCl? was six times that obtained using Ni. The in-situ measurements using Co dendrites on the Ni foam as anode and Prussian blue as cathode catalyst demonstrated a 21 mWcm? 2 at 20 ?C. These are the first reported results for a complete Ni-free nonprecious anode and cathode catalysts under real fuel cell operation with high performance comparable to those obtained using precious catalyst under same conditions.

Automated summary

Mesoporous Co dendrites prepared by electroplating exhibit a high surface area and superior urea oxidation activity compared to Ni or Co nanoparticles prepared using chemical reduction. The Co dendrites show a lower onset potential and higher current output than Ni catalyst under experimental conditions, achieving a good output performance even at 20℃. These results demonstrate the potential of using nonprecious Co dendrites as anode and cathode catalysts in fuel cell applications.