Single-walled carbon nanotubes (CNTs) were dispersed in toluene by ultrasonication for several hours. Typically, 5 mg of purified crystals was mixed with 0.75 mg of the CNTs dispersed in toluene. After a brief ultrasonication for a minute or less, the mixed solution was filtered by a polytetrafluoroethylene (PTFE) membrane (diameter 25 mm, pore size 0.22 µm). A MOF@CNT film (16 mm diameter) on the membrane was dried and used as cathode.