Corrosion inhibitor in CO2-O2-containing environment: Inhibition effect and mechanisms of Bis(2-ehylhexyl) phosphate for the corrosion of carbon steel

•BEP can effectively protect carbon steel from corrosion in CO2–O2–containing environment.•BEP anion is much easier to adsorb on iron surface than O2.•Inhibition layer binds with steel surface via P–O–Fe bond and P–Fe bond. The corrosion inhibition of carbon steel in CO2-O2-containing environment is one of the biggest challenges in flue gas injection for enhanced oil recovery. Herein we report the possibility to use Bis(2-ehylhexyl) phosphate (BEP) to inhibit the corrosion in CO2-O2-containing solution and simultaneously the inhibition mechanisms are unmasked. The results show that the corrosion is greatly inhibited with 500 ppm BEP in 1 wt% NaCl solution with 0.02 MPa CO2 and 3 mg/L O2. BEP could interact with Fe and corrosion products via the formation of P-O-Fe bond and P-Fe bond to generate a barrier layer, thus, offering a protective performance.