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.

Automated summary

The conjugated polymer polypyrrole (PPy) was used to decorate ZnTi hydrotalcite (ZnTi-LDH) to construct an organic-inorganic PPy/ZnTi-LDH composite, which exhibited superior photocatalytic performance and stability under visible light irradiation for Cr(VI) reduction. The enhanced photocatalytic performances were attributed to the combined effect of ZnTi-LDH structure and conductive PPy facilitating charge transfer and increasing visible-light absorption. The crucial role of PPy in Cr(VI) reduction and the proposed photocatalytic reaction mechanism were also discussed.