Photocatalytic performance of carbonaceous TiO<SUB align='right'>2 nanotube arrays for degradation methyl orange dye under UV light

Carbon-doped TiO2 nanotube arrays (TNAs) were prepared from carbonaceous Ti foils by anodisation in a mixed electrolyte of glycerol and water. The photocatalytic ability can be increased by applying an external positive bias. Enhancing acidity of the pending solution can further accelerate the degradation rate. However, falcate and annular scraps were observed on the surface of TNAs after photoelectrodegradation experiments. XPS analysis indicated that carbon ions were positioned in interstitial site of the catalyst and the carbon content in TNAs decreased following the degradation process. The acid environment can increase the photocatalytic activity; this will damage the C-TNAs greatly. The carbon content decrease from 18.47 at. % to approximate 6 at. % after PEC processes, indicating that the carbon elements is removed from carbonaceous C-TNAs during PEC.