Organic semiconductor g-C3N4 modified TiO2 nanotube arrays for enhanced photoelectrochemical performance in wastewater treatment

Abstract

g-C3N4 sensitized TiO2 nanotube arrays (g-C3N4/TNTs) were fabricated by a simple solid sublimation and transition (SST) method using urea as precursor. The photoelectrochemical (PEC) performances were evaluated in this work. It is proposed that the g-C3N4 layer can play dual roles: surface sensitization and passivation of TNTs surface trap states to inhibit charge recombination. The g-C3N4/TNTs exhibited significantly improved PEC performance compared with TNTs under blue light (460 nm) irradiation. The g-C3N4/TNTs prepared from 3 g urea showed the highest photocurrent density of ca. 65 μA cm-2, which is almost 10 times as high as that of TNTs. Furthermore, g-C3N4/TNTs showed enhanced photoelectrocatalytic degradation of methylene blue (MB) under the blue light irradiation. The stable performance of degradation of MB in the multicycle tests suggests that the hybrid g-C3N4/TNTs electrode could be used as a low-cost photoelectrode material in wastewater treatment process.