Carbon quantum dots (CQDs) modified TiO2 nanorods photoelectrode for enhanced photocathodic protection of Q235 carbon steel

Abstract A new photoanode of Al2O3 anchored carbon quantum dots/TiO2 nanorods (Al/C/TNRs) was constructed for efficient photocathodic protection of Q235 carbon steel (CS) by hydrothermal treatment and ALD process. The Al/C/TNRs photoanode achieved a photocurrent density of 2.28 mA/cm2 under simulated sunlight (AM 1.5 G), and could maintain for 7 days nearly without decay. Potential of Q235 CS was negatively shifted by 620 mV after coupling with Al/C/TNRs in 3.5 wt% NaCl solution, and could maintain more than 7 hours. The high and stable photoelectrochemical performances of Al/C/TNRs indicate potential photocathodic protection for Q235 CS in marine environment.