Activation Factors of the Oxygen Reduction Reaction on Pt3Co Alloy Single Crystal Electrode in Diethylmethylammonium Triflate [dema][TfO]

Increasing the activity of oxygen reduction reaction (ORR) is an important subject for the development of a fuel cell.Operation temperature of a fuel cell of a heavy-duty vehicle (HDV) is more than 100 °C, and the combination of ionic liquids and Pt alloy catalysts can contribute to the increase of the ORR activity at more than 100°C.We have studied the ORR activity on single crystal electrodes of Pt3Co in diethylmethylammonium triflate ([dema][TfO]).The activity of the ORR at 0.9 V(RHE) at 120 °C increases as Pt3Co(111) < Pt3Co(110) < Pt3Co(100).This order of the activity completely differs from that in 0.1 M HClO4: Pt3Co(100) < Pt3Co(110) < Pt3Co(111).The activity of Pt3Co(100) in [dema][TfO] at 120 °C was higher than that in 0.1 M HClO4 at 25 °C.The ORR current densities at 0.6 V(RHE) in [dema][TfO] at 120 °C exceed the limiting current densities in 0.1 M HClO4 at 25 °C on all the surfaces.The Arrhenius plots show that the frequency factor depends on the surface structure markedly: Pt₃Co(111)