▎ 摘　　要

NOVELTY - Preparing manganese dioxide/silver composite nanomaterial based graphene/carbon nanotube comprises e.g. acidifying multi-walled carbon nanotubes, adding tris(hydroxymethyl)aminomethane into mixed solvent consisting of isopropanol and pure water, stirring to dissolve, adding acidified CNT particles, ultrasonicating resulting mixture, adding dopamine, mixing graphene oxide with pure water, ultrasonically dispersing, mixing CNT-PDA with pure water, mixing CNT-PDA-GO particles with pure water, ultrasonically dispersing, adding AgNO3 solution into CNT-PDA-GO dispersion and washing with pure water. USE - The nanotube is useful for electrocatalytic activity determination of oxygen reduction reaction (ORR) and oxygen precipitation reaction (OER) (claimed); as cathode material in charge metal-air battery. ADVANTAGE - The nanotube has excellent catalytic activity, high electro-catalysis activity for ORR and high electrical activity to OER. DETAILED DESCRIPTION - Preparing manganese dioxide/silver composite nanomaterial based graphene/carbon nanotube comprises (i) acidifying multi-walled carbon nanotubes (CNTs), adding tris(hydroxymethyl)aminomethane into mixed solvent consisting of isopropanol and pure water, stirring to dissolve, then adding acidified CNT particles, ultrasonicating resulting mixture, adding dopamine, stirring at room temperature, reacting, centrifuging and separating, washing resulting solid and vacuum drying at 60 degrees C to obtain CNT-PDA, (ii) mixing graphene oxide (GO) with pure water and ultrasonically dispersing to obtain GO dispersion at concentration of 0.4 mgml-1, then mixing CNT-PDA with pure water, ultrasonically dispersing to obtain CNT-PDA dispersion at concentration of 1.5 mgml-1, then mixing above two dispersions, stirring, centrifuging, washing resulting solid with pure water and drying under vacuum at room temperature to obtain CNT-PDA-GO, (iii) mixing CNT-PDA-GO particles with pure water and ultrasonically dispersing to obtain CNT-PDA-GO dispersions at concentration of 5 mgml-1, then ultrasonically agitating, adding 10 mmol l-1 concentration of silver nitrate solution into CNT-PDA-GO dispersion, ultrasonically stirring, centrifuging, washing with pure water and vacuum drying resulting solid at 60 degrees C to obtain CNT-PDA-GO-Ag, (iv) reacting CNT-PDA-GO-Ag solid under nitrogen atmosphere, heating at rate of 5 degrees C min1 at 800 degrees C, insulating for period of time and then naturally cooling to room temperature to obtain CNT-C-N-rG-Ag, and (v) mixing CNT-C-N-rG-Ag particles with MnSO4 solution, stirring mixture, heating under water bath at 80 degrees C, adding potassium permanganate solution, then stirring, cooling mixture to room temperature, filtering resulting solid, washing and vacuum drying at 40 degrees C to obtain CNT-PDA-rG-Ag-MnO2 i.e. manganese dioxide/silver composite nanomaterial, where concentration of MnSO4 solution is 2-20 mol l-1 and potassium permanganate solution has a concentration of 2 to 20 mol l-1.