Photoelectrochemical performance of BiOI/TiO2 Nanotube Arrays (TNAs) p-n heterojunction synthesized by SILAR-ultrasonication-assisted methods
Data files
Jun 06, 2023 version files 1.17 MB
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README.md
Abstract
In order to extend the visible region activity of titania nanotube array (TNAs) films, the Successive Ionic Layer Adsorption and Reaction (SILAR)-ultrasonication-assisted method has been used to prepare BiOI-modified TiO2 nanotube arrays (BiOI/TNAs). The band gap of BiOI/TNAs for all the variations reveals absorption in the visible absorption. The surface morphology of BiOI/TNAs is shown in the nanoplate, nanoflake, and nanosheet forms with a vertical orientation perpendicular to TiO2. The crystalline structure of BiOI did not change the structure of the anatase TNAs, with the band gap energy of the BiOI/TNAs semiconductor in the visible region. The photocurrent density of the BiOI/TNAs extends to the visible-light range. BiOI/TNAs with 1 mM Bi and 1 mM KI on TNAs 40 V 1 h 50 V 30 min shows the optimum photocurrent density. A tandem dye-sensitized solar cell (DSSC)-photoelectrochemical (PEC) was used for hydrogen production in salty water. BiOI/TNAs optimum was used as the photoanode of the PEC cell. Solar to hydrogen conversion efficiency (STH) of tandem DSSC-PEC reaches 1.34% in salty water.
Methods
TNAs were synthesized by modifying the second-step potentials of the two-step anodization method. The applied potential used in the first step method was fixed at 40 V for 60 min, and the second step anodization voltage was 50 V with various anodization times, i.e., 15 min, 30 min, and 60 min. BiOI/TNAs were prepared through the SILAR-ultrasonication-assisted method. The cationic precursor was used Bi(NO3)3.5H2O with various concentrations, and a solution of KI with various molar ratios was used as the anionic precursor. Deionized water was used as the solvent to dilute the precursors. TNAs foil was immersed in the cationic precursors with a time variation of 10 s, 45 s, and 90 s., followed by immersion in deionized water. After that, the TNAs foils were immersed in anionic precursors solution and then deionized water immersion to remove the not adsorbed ion. SILAR cycles, the concentration of the precursors, and immersion time were varied to get the optimum condition. BiOI/TNAs dried in open-air conditions. SILAR-Ultrasonication assisted illustration is shown in Figure.1. For comparison, BiOI/TNAs also prepared by SILAR without ultrasonication assisted, that symbolized by S (SILAR without ultrasonication assisted).