| 초록 |
The metal–organic framework (MOF) is composed of a metal ion and an organic linker. It has high porosity and high electrochemical catalytic activity. Herein, ZIF-67 was combined with activated carbon through ultrasonication (U) and solution precipitation (H). In maximum power density, ZIF-67U cathode produced 4203 mW m−2, and ZIF-67H did 3881 mW m−2, which is 60% and 48% higher than activated carbon (AC) cathode (2625 mW m−2) and 160% and 140% higher than Pt cathode (1614 mW m−2), respectively. Cobalt and nitrogen contents increased in the ZIF catalysts. In atomic nitrogen contents of catalyst surface, pyridine-N was 28% in ZIF-67U and 38% in ZIF-67H; pyrrole-N was 56% in ZIF-67U and 25% in ZIF-67H; no nitrogen was detected in AC. These cobalt-nitrogen increased the active site of the oxygen reduction reaction (ORR), improved the reaction rate, and decreased charge transfer impedance. AC and ZIF-67 were bonded using ultrasonication and tested in the MFC for the first time, producing the highest power ever among the MOFs in the 50-mM phosphate-buffer-saline condition so far. |
