Photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant on highly smooth and ordered TiO2 nanotube arrays

The photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant were achieved on TiO2 nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. The TiO2 nanotube arrays (TiO2 NTs) were fabricated by a two-step anodization method. The TiO2 NTs prepared in two-step anodization process (2-step TiO2 NTs) showed much better surface smoothness and tube orderliness than TiO2 NTs prepared in one-step anodization process (1-step TiO2 NTs). In the photoelectrochemical water splitting and simultaneous photoelectrocatalytic decomposition process, the 2-step TiO2 NTs electrode showed both highest photo-conversion efficiency of 1.25% and effective photodecomposition efficiency with existing of methylene blue (MB) as sacrificial agent and as pollutant target. Those results implied that the highly ordered nanostructures provided direct pathway and uniform electric field distribution for effective charges transfer, as well as superior capabilities of light harvesting.

Graphical AbstractThe photoelectrochemical water splitting for hydrogen generation and simultaneous photoelectrocatalytic degradation of organic pollutant (methylene blue) were achieved on TiO2 nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► TiO2 nanotube arrays were fabricated by a two-step anodization method. ► Hydrogen generation and organic pollutant degradation were achieved on TiO2 NTs. ► Highest photoconversion efficiency of 1.25% was achieved. ► Increasing orderliness will increase photocatalytic activity of TiO2 NTs.