Flow-type hydrogen peroxide fuel cells with hemin-modified buckypaper catalysts

In this study, a new cathodic catalyst including hemin catalyzing the H₂O₂ reduction reaction (HPRR) is suggested to improve the performance of flow-type hydrogen peroxide fuel cells (HPFCs). To develop the hemin-based catalyst showing excellent HPRR reactivity, buckypaper (BP) and polyethyleneimine (PEI) are used, and it is proved that the final [BP/hemin]/PEI/hemin catalyst has excellent catalytic activity in terms of current and onset potential for the HPRR. To evaluate the effect of the catalyst on the performance of HPFC, BP/hemin and BP/PEI/hemin catalysts as the control groups are fabricated and compared. When [BP/hemin]/PEI/hemin is used, the amount of immobilized hemin and the reactivity of the HPRR increase due to the interstitial pores of the carbon nanotube network. Furthermore, its onset potential increases due to the formation of the coordinate bond between the iron core within hemin and the axial ligand within PEI. For preparing membraneless HPFCs, flexible materials such as hemin-modified BP, carbon cloth and polyethylene terephthalate are used, and its open circuit potential and maximum power density are 0.171 ± 0.012 V and 90.7 ± 6.88 μW cm⁻² when 0.1 M H₂O₂ is injected. These results are far better than those of other previous studies.