High Power Density of a Hydrogen Peroxide Fuel Cell Using Cobalt Chlorin Complex Supported on Carbon Nanotubes as a Noncorrosive Anode.

Hydrogen peroxide fuel cells (HPFCs) have attracted much attention due to their simple one-compartment structures and high availability under harsh conditions such as an anaerobic environment; however, catalysis improvement is strongly demanded for both anodes and cathodes in terms of activity and durability. Herein, we report the high catalytic activity of Co II chlorin [Co II (Ch)] for hydrogen peroxide (H 2 O 2 ) oxidation with a low overpotential (0.21 V) compared to that of the Co II phthalocyanine and Co II porphyrin complexes, which have previously been reported as active anode catalysts. Linear sweep voltammograms and differential pulse voltammograms of the Co II complexes (Co II L) and the corresponding ligands clearly showed that the Co III L species are the active species for H 2 O 2 oxidation. Then, one-compartment HPFCs were constructed with Co II (Ch) supported on multiwalled carbon nanotubes (CNTs) as the anode together with Fe II 3 [Co III (CN) 6 ] 2 supported on CNTs as the cathode. The maximum power density of the HPFCs reached 151 μW cm -2 with an open circuit potential of 0.33 V when the coverage of CNT surfaces with Co II (Ch) exceeded ∼60% at the anode.