A one-step electrodeposition of hydrangea-like Cu2O on activated carbon as air cathode for microbial fuel cells (MFCs) was demonstrated. The addition of polyvinylpyrrolidone (PVP) surfactant oriented the crystal growth of Cu2O to achieve a highly ordered porous structure to accommodate the reactants diffusion. In addition, the chemical properties of carbon surface were modified by the PVP aided process. The optimized PVP aided Cu2O delivered a maximum power density of 1610 +/- 30 mW m(-2), significantly outperforming the non-PVP aided Cu2O and bare active carbon. The remarkable improvement in the activity toward oxygen reduction reaction (ORR) was attributed to the lower charge transfer resistance, higher exchange current density and lower activation barrier. Comprehensive characterizations were performed. It was suggested that the formation of C-N active sites, the surface functional groups, and oxygen vacancies contributed to the promotion of ORR and overall cell performance. As a result, hydrangea-like Cu2O, which possessed great catalytic performance, will have a promising outlook applied in MFC. (C) 2017 The Electrochemical Society. All rights reserved.