Fluorine doping of α-alumina for regulating ozone activation to selectively generate hydroxyl radicals

Facile sol-gel fabrication of F@Al 2 O 3 rich in oxygen vacancies was achieved. • Oxygen vacancies facilitate the formation of hydrated -OH via water dissociation. • F doping narrows the band-gap of α-Al 2 O 3 and enhances electron transition ability. • The formed hydrated -OH effectively improves the selectivity of •OH generation. Hydroxyl radical (•OH) is a type of excellent reactive oxygen species (ROS) for the efficient degradation of organic pollutants, usually occurs in advanced oxidation processes (AOPs). The α-alumina (α-Al 2 O 3 ) is one of the few nanomaterials produced on a ton-scale and successfully utilized in large-scale water treatment. However, its role in AOPs has primarily been limited to serving as an inert support due to its insufficient active sites and gradual consumption of the surface hydroxyl groups, leading to the function-guide generation of •OH in AOPs is still challenging. Herein, we precisely regulate ROS generation in ozone (O 3 )-based AOPs by doping engineering to enhance the catalytic capability of α-Al 2 O 3 for efficiently eliminating organic pollutants. Fluorine-doped α-alumina (F@Al 2 O 3 ) facilitates O 3 activation via a radical pathway with 95.7% •OH, delivering boosted performance for degradation of atrazine from water, which is 5.6 and 2.1 times that of non-catalytic ozonation and O 3 /α-Al 2 O 3 , respectively, exceeding most reported O 3 -based catalysts. The lattice doping of F into α-Al 2 O 3 via F Al coordination effectively reduces the local electron density around Al sites to form hydrated hydroxyl groups, thus facilitating O 3 adsorption and lowering the energy barrier of the rate-limiting step during O 3 activation for •OH generation. The simple lattice-doping engineering doubles the catalytic capability of α-Al 2 O 3 by the precise regulation of ROS generation, which rendering α-Al 2 O 3 an extremely promising nanomaterial for advanced water treatment. Download: Download high-res image (153KB) Download: Download full-size image