2D Fe/Co and N/B codoped mesoporous carbon nanosheets (FeCo/NB-Cs) were ingeniously synthesized to strategically boost kinetics of oxygen reduction/evolution reaction (ORR/OER) by a facile but advanced route. The FeCo/NB-Cs display ultrahigh specific surface area (SSA) of 1584 m(2) g(-1) and total pore volume (TPV) of 1.21 cm(3) g(-1), higher than most of currently reported M-N-C catalysts. Delightfully, FeCo/NB-Cs also exhibit obvious mesoporous properties via easy tailoring of H3BO3 dopant. Without doubt, FeCo/NB-Cs exhibit remarkable ORR/OER catalytic activity (total overpotential, Delta E=0.653 V), exceeding most of reported heterogeneous-doped carbon materials. Meanwhile, the FeCo/NB-Cs based zinc-air batteries display high power density and perfect charge-discharge stability. More significantly, theoretical calculation reveals that greatly enhanced catalytic activity of FeCo/NB-Cs originates from higher HOMO (highest occupied molecular orbitals) energy, higher DOS (density of states) and weakened O-2 adsorption strength owing to synergetic contribution of Fe/Co and N/B dopants. Consequently, this work not only provides a facile but advanced avenue to rationally design heterogenous-doped carbon nanosheets with high SSA and large TPV but also reveals the insight understanding for synergetic contribution of different active species.