Synthesis and characterization of N-doped carbonaceous/TiO2 composite photoanodes for visible-light photoelectrocatalytic inactivation of Escherichia coli K-12

Abstract

The N-doped carbonaceous/TiO2 composite photoanodes were fabricated by a facile hydrothermal-calcination approach using melamine as a precursor for N-doped carbonaceous species, and Ti foil as titanium source. The results showed that the N-doped carbonaceous materials with various organic functional groups were uniformly deposited onto TiO2, and the hydrothermal temperature had significant effects on the phase of TiO2, element composition, surface morphology and photocatalytic activity of the composite photoanodes. Escherichia coli K-12 was chosen as the model bacterium to evaluate the photoelectrocatalytic activity of the composite photoanodes under visible light irradiation. Under a constant potential bias of +1.0 V and a light intensity of 15 mW/cm2, 107 cfu/mL E. coli could be completely inactivated within only 30 min by using the composite photoanodes obtained from 120 àhydrothermal treatment. The high photoelectrocatalytic bactericidal activity of composite photoanodes under visible light irradiation was mainly due to the synergistic effect between N-doped carbonaceous and TiO2 components, benefiting the light absorption and the effective charge separation.