Evaluation of visible-light driven photocatalytic reaction by porphyrin coupled TiO2 nanotubes obtained via rapid breakdown anodization

Abstract

The perceived attraction of nanotubular TiO2 in diverse applications has brought the researchers attention to focus on various aspects of nanotube synthesis and modification. In this work, the visible light activity of dye sensitized TiO2 nanotubes obtained in powder form via rapid breakdown anodization was investigated. Tetra (4-carboxy phenyl) porphyrin (TCPP) was used as a visible light sensitizing component on phase pure anatase TiO2 nanotubes (ATiNT). The effect of introducing two different anchoring groups between the dye and TiO2 nanotubes on photocatalytic activity was investigated. The visible light photocatalytic efficiency of the prepared ATiNT/TCPP composites was tested on a pharmaceutical compound, famotidine (FAM) in order to avoid degradation through photosensitization. For the given amount of TCPP load on ATiNT, the presence of a lengthy anchoring group between TCPP and ATiNT had a negative influence on the photocatalytic activity. Direct oxidation through visible-light-generated holes in the ATiNT/TCPP composite appeared to be the most significant pathway for FAM photocatalysis.