This work addresses the substantial effect of oxygen co-insertion into boron-doped porous carbon (BPC) on the activity of the oxygen reduction reaction (ORR). The BPC synthesis is based on simple CO2 carbonization using NaBH4 as a reducing agent with subsequent thermal treatments. Electrochemical, microscopic and spectroscopic measurements with density functional calculations reveal that the presence of oxidized boron atoms (O-B-C species) in the B-C bonding is responsible for the enhanced ORR activity, preferential 4 electron pathway, and high cycle stability.