Manganese oxide nano flakes onto simultaneously activated defective CNTs for the creation of CNTs-graphene supported oxygen reduction composite catalysts applied in air fuel cell

摘要

Rational combination holds the key for non-precious metal oxides and economiccarbon materials to the creation of high performance air electrode materials.Carbon nanotubes (CNTs)-supported manganese oxides composite catalysts (CMnCs)were obtained by reacting commercial CNTs with MnO$_4^-$ in diluted H$_2$SO$_4$with cancelling conventional hydrothermal processing or adding surfantanttemplates. CMnCs were then assembled into commercial air cathodes equipped inmetal air fuel cells. CNTs demonstrated structurally much defective. Outer CNTwalls were cracked into graphene nano pieces yet remaining partially attachedto inner carbon tubes during synthesis. This exposure of graphene planesexhibited additional oxygen reduction reactivity. Manganese oxide flakesidentified as {\gamma}-MnOOH were homogeneously grown on surfaces of CNTs atnano sizes. Its deposition density was closely related to the additive amountof KMnO$_4$ with regard to CNTs. The ORR activities of sole CMnCs exceeded bothraw CNTs and competent market catalysts under identical conditions, and withcurrent production technics the CMnCs-ingrediented air fuel cells were capableof outputting ~15% more power at 100 mA/cm$^2$.