Two-dimensional layered organic hybrid selenidostannate coupled with polyaniline for high efficient photocatalytic Cr(VI) reduction

Abstract

Given the threat of Cr(VI) to the environment and human health, it is urgent to develop new photocatalysts for efficient photocatalytic reduction of Cr(VI). Herein an organic hybrid selenidostannate [Ni(phen)3][Sn3Se7]·1.5H2O (NPTS) was coupled with polyaniline (PANI) to form NPTS@PANI-x (x = 15, 50, 100) composites, where all the NPTS@PANI-x composites surprisingly exhibited excellent photocatalytic performances for Cr(VI) reduction. In particular, NPTS@PANI-15 can reduce 100% of Cr(VI) (100 mg/L) in 10 min. Moreover, NPTS@PANI-15 possesses a strong ability to resist interference from various anions, cations, and NOM. In addition, under sunlight irradiation, NPTS@PANI-15 can reduce 100% of Cr(VI) (100 mg/L) in 15 min. The superior photocatalytic performance of NPTS@PANI-15 can be attributed to three factors: Firstly, the large distance between the [Sn3Se7]n2n– layers could offer sufficient space for transporting Cr(VI) into the interlayers; Secondly, the [Ni(phen)3]2+ cations located between the [Sn3Se7]n2n– layers can interact with Cr(VI) oxyanions via electrostatic attraction, and thereby promote the adsorption of Cr(VI); and Thirdly, the coupling of NPTS and PANI accelerates the separation rate of electron-hole pairs, which facilitates the Cr(VI) reduction process. Our research demonstrates that organic hybrid metal chalcogenides can be used as a new type of high efficiency photocatalyst for Cr(VI) reduction.