Enhanced photoelectrocatalytic activity of reduced graphene oxide/TiO2 composite films for dye degradation

Abstract

Titanium dioxide (TiO2) and reduced graphene oxide (RGO) composite films, constructed via post treatment of as-prepared graphene oxide (GO)/TiO2 films, were firstly employed as photocatalyst for dye degradation in the photoelectrocatalytic (PEC) process. The resultant films were characterized by scanning electronic microscopy (SEM), X-ray diffractometer (XRD), Brunauer–Emmett–Teller (BET) surface area, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectra. Electrochemical impedance spectra (EIS) and photocurrent density measurements revealed that the incorporation of RGO in the films significantly decreased the charge transport resistance and improved the photocurrent response. In the following degradation processes, it was found that PEC performance of the films depended largely on different post treatment processes chosen and the RGO contents. Compared with pure TiO2 film, approximately fourfold and fivefold enhancement in the PEC degradation rate toward rhodamine B (RhB) and acid orange II (AO-II) was obtained over the optimized RGO/TiO2 film. The enhanced PEC activity might be mainly attributed to the role of RGO played as electron acceptor and transporter in the composite film, which effectively suppressed the charge recombination and promoted the charge transfer within the film.