Improved solar-driven photocatalytic performance of BiOI decorated TiO2 benefiting from the separation properties of photo-induced charge carriers

• BiOI was applied to modify TiO2.
• The photo-induced charge separation rate has been enhanced.
• BiOI/TiO2 exhibits different electronic transfer properties.
• The photocatalytic activity of TiO2 has been greatly promoted.

In this work, BiOI decorated TiO2 photocatalysts were prepared in-situ by a facile hydrothermal method and characterized by X-ray diffraction (XRD), UV/Vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and surface photovoltage (SPV) spectroscopy. The reactive radicals during the photocatalytic reaction were detected by scavenger experiments. BiOI/TiO2 composites exhibit higher performance than the pure TiO2 towards photocatalytic decolorization of methyl orange (MO) aqueous solution, when the molar ratio of Bi/Ti is 2%, the sample has the highest photocatalytic activity. The enhanced photocatalytic performance of BiOI/TiO2 could be ascribed to the separation properties of photo-induced charge carriers and strong interaction between BiOI and TiO2. Based on the observations, a Z-scheme charge separation mechanism was proposed.

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