doi:10.1038/nindia.2015.110 Published online 2 September 2015
Researchers have synthesised a novel catalyst by depositing platinum nanoparticles on DNA-coated graphite nanofibres1. They found that this catalyst efficiently catalyses the oxygen reduction reaction, making it potentially useful for polymer electrolyte fuel cells.
Polymer electrolyte fuel cells can operate at low temperatures and are thus used to power vehicles and portable devices. The fuel cells convert energy through the oxygen reduction reaction. Slowing of this reaction could limit the energy conversion efficiency of fuel cells.
To speed up the oxygen reduction reaction, the researchers fabricated a catalyst by wrapping graphite nanofibres with DNA molecules and then dispersing spherical platinum nanoparticles on the DNA-coated graphite nanofibres.
The researchers measured the efficiency of the catalyst by performing electrochemical measurements on a rotating-disk electrode in an acidic solution at room temperature. When they compared this measured performance with those of commercial catalysts, they found that the DNA-based catalyst exhibited a 3.5 times higher mass activity in reducing oxygen than commercial catalysts such as a platinum–carbon catalyst.
The catalyst was also more stable than the commercial ones: after 10,000 electrochemical cycles, the DNA-based catalyst lost 48 per cent of its original efficiency, whereas platinum–carbon and platinum–graphite nanofibre catalysts lost 67 per cent of their original efficiencies.
The researchers attributed the superior activity of the DNA-based catalyst to the transfer of specific electrons between graphite nanofibres and the DNA, which prevents the aggregation of platinum nanoparticles even after repeated activity cycles.
1. Peera, S. G. et al. Deoxyribonucleic acid directed metallization of platinum nanoparticles on graphite nanofibers as a durable oxygen reduction catalyst for polymer electrolyte fuel cells. J. Power Sourc. 297, 379–387 (2015)