Engineering / Carbon Nanotube / Cyclic Voltammetry / Power / Electron Transfer / High Resolution Transmission Electron Microscopy / CHEMICAL SCIENCES / Supercritical carbon dioxide / Surface Area / X ray diffraction / Oxygen Reduction Reaction / Oxygen Reduction / Power Sources / High Resolution Transmission Electron Microscopy / CHEMICAL SCIENCES / Supercritical carbon dioxide / Surface Area / X ray diffraction / Oxygen Reduction Reaction / Oxygen Reduction / Power Sources