Enhanced photoelectrocatalytic performance of titanium dioxide/carbon cloth based photoelectrodes by graphene modification under visible-light irradiation

Abstract

Reduced graphene oxide nanosheets modified TiO2 nanospheres on carbon cloth electrodes (RGO/TiO2/CC) have been fabricated and used for photoelectrocatalytic (PEC) degradation of organic pollutants under visible light irradiation. The fabricated RGO/TiO2/CC electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. Compared with TiO2/CC electrode, the RGO modified TiO2/CC electrode evidently shows improved visible light-driven PEC activity for degradation of an often used model pollutant, methylene blue (MB). Moreover, the efficiency of MB degradation by PEC process (0.0133min−1) is about 13-fold and 7-fold faster than that of electrochemical process (0.001min−1) and photocatalytic process (0.0018min−1), respectively. The improved catalytic activity for PEC degradation of MB pollutants could be attributed to the existence of RGO, which extends the absorption onset of TiO2 to longer wavelength direction and promotes the separation of electron–hole pairs generated under visible light irradiation. The promotion effect on the electron–hole separation is supported by photocurrent and electrochemical impedance measurements. In addition, a synergetic effect of photocatalysis and electrocatalysis is involved in the PEC process, by which the recombination of photogenerated electron–hole pairs is significantly suppressed.