The practical implementation of air-breathing microbial fuel cell (MFC) is critically linked to the development of efficient materials as cathode and electrochemically active biofilm-based anode. In this contribution, we demonstrate the feasibility by decorating a 3D carbon felt electrode with Pt nanoarrays (CF@Pt) as a bifunctional electrode material as efficient garden compost bioanode and airbreathing cathode. Half-cell electrochemical characterizations reveal that the onset potential of the anode reaction negatively shifts of about 800 mV to reach −0.4 V vs Ag/AgCl after the growth of the biofilm onto CF@Pt. The investigation before and after the biofilm formation shows that Pt nanoarrays act as excellent electron relays, reducing significantly the charge transfer resistance. For MFC application (with a proton exchange membrane), the use of CF@Pt as bioanode' scaffold and CF@Pt air-cathode enables a drastically enhanced power density of P max = 292.3 mW m −2 , and a high short-circuit current density j sc = 1.9 A m −2 .