fig4

Figure 4. (A and B) SEM image of cathode (left) and anode (right) of PMMFCs with NF-GO-H electrode; (C and D) SEM image of cathode (left) and anode (right) of PMMFCs with NF-GO-L electrode. PMMFCs: Photosynthetic microalgae microbial fuel cells; SEM: scanning electron microscope.