Electrochemical anodization of graphite oxide-TiO 2 nanotube composite for enhanced visible light photocatalytic activity

Abstract

The electrochemical anodization method was used to dope graphite oxide (GO) onto TiO₂ nanotubes (TNTs). This study focused on enhancement of the photocatalytic activity of TNTs in the visible light region. In this study, we have checked the effect of different GO concentrations and effect of GO doping time on photocatalytic efficiency of composite. The photocatalytic activity of the GO-TNT composite was tested by degradation of an organic compound. The organic compound was most severely degraded (95%) when the GO-TNT catalyst was doped at an anodization of 60 V for 13 min and GO concentration of 0.25 g L⁻¹. This degradation was 5.6 times higher than that of bare TiO₂. The as-prepared catalyst was characterized using FE-SEM, XRD, AES, PL, UV-Vis DRS, and Raman analysis. Recycling of the GO-TNT composite was also performed in order to examine the stability of the visible light catalyst. We observed that the doping of GO on the TNT surface can enhance the photocatalytic efficiency under visible light. Graphene acts as an electron transport; therefore, GO-TNTs were favorable for the separation of e⁻ and h⁺ charges. This promoted the formation of OH radicals, h⁺, and superoxides, all of which degrade organics.

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