Single iron atoms anchored on activated carbon as active centres for highly efficient oxygen reduction reaction in air-cathode microbial fuel cell

Microbial fuel cells are an emerging bio-battery that has attracted much attention due to its integration of power generation and wastewater treatment. However, the sluggish oxygen reduction reaction hinders its practical application. It Is necessary to develop a high-performance catalyst for oxygen reduction reaction. Here, we report single iron atoms loaded on activated carbon as active centres used in microbial fuel cell that shows a maximum power density of 2264 +/- 46 mW m(-2), which is 156% higher than that of the bare activated carbon and comparable to commercial Pt/C. In addition, the higher exchange current density (16.069 x 10(-4) A cm(-2)) and the efficient 4-electron pathway also verify its remarkable catalytic property. Moreover, we employ the aberration-corrected high-resolution high-angle annular dark-field scanning transmission electron microscopy and scanning electron microscopy to directly identify the single iron atoms on the carbon material and observe the morphology of catalyst, respectively. Besides, its large specific surface area (339.8 m(2) g(-1)) and co-existence of microporous and mesoporous can promote the oxygen mass transfer and stabilize the single Fe atoms. In summary, the activated carbon-supported single iron atoms material can be a promising and highly efficient catalyst for future application.