Electrochemical synthesis of co-doped RGO-Bi-TiO2 nanotube composite: Enhanced activity under visible light

Abstract

TiO2 nanotube (TNT) photocatalyst with enhanced visible-light activity was synthesized by co-doping with reduced graphene oxide (RGO) and bismuth (Bi). The RGO-Bi-TNTs composite was fabricated using three different approaches: one-step, two-step, and three-step electrochemical anodization. The synthesized catalyst was characterized by FE-SEM, XRD, AES, and PL. Co-doping optimum synthesis using three-step method accomplished 1.5 and 3.8-times higher photocatalytic activity than single-doping and undoped-TNTs, respectively under same conditions. RGO and Bi were favorable for separation of e(-) and h(+), which reduced recombination of charges. This result promoted the formation of OH radicals and increased photocatalytic efficiency of TNTs under visible light.