In this study, bacterial cellulose doped with phosphorus and copper via freeze-drying and high-temperature pyrolysis was used to prepare MFC cathode catalysts. After a series of characterization, the synthesized catalyst showed a three-dimensional network with a specific surface area of 580.09 m2/g. Due to the doping of Cu and P, more active sites were induced in the pores of bacterial cellulose and subsequently improved catalytic activity. The prepared catalyst was coated on the air cathode surface of the MFC to obtain the maximum output power and current density of 1177.31 mW/m2 and 6.73 A/m2, respectively, which were higher than those of Pt (1044.93 mW/m2 and 6.02 A/m2). This work aimed to improve bioelectrical generation in MFC and find alternative commercial Pt catalysts.