Polypyrrole decorated ZnTi hydrotalcite with enhanced adsorption and Cr(VI) photoreduction activity under visible-light

A conjugated polymer polypyrrole (PPy) was used to decorate the ZnTi hydrotalcite (ZnTi-LDH) for con-structing an organic-inorganic PPy/ZnTi-LDH composite by a facile in-situ oxidation polymerization. It was found that the as-prepared composite displayed a superior photocatalytic performance and excellent stability under visible light irradiation, which Cr(VI) reduction efficiency (99.72% for 35 min) was around 53 and 12 times higher than those of the pristine ZnTi-LDH and pure PPy, respectively, and still main-tained 95.10% even after 5th cycles. The dramatically enhanced photocatalytic performances were attrib-uted to the beneficial combination of the ZnTi-LDH stratified structure and conductive PPy, which effectively facilitated charge transfer, restrained recombination, and increased visible-light absorption. Particularly, PPy as a remarkable conductive polymer, played a crucial role in the Cr(VI) reduction, which not only was a light acceptor to produce photo-generated charge carriers but also provided a good elec-tron transport path to accelerate the separation and migration of electron-hole pairs to improve the pho-toreduction performances. Finally, possible photocatalytic reaction mechanism of the PPy/ZnTi-LDH was also proposed. (c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.