Cr(VI)-imprinted polymer wrapped on urchin-like Bi2S3 for reduced photocorrosion and improved photoreduction of aqueous Cr(VI)

Just like other metal sulfides, the misfortune of photocorrosion and undesired photogenerated electron-hole recombination for Bi2S3 was inevitable. In this work, a viable route to reduce photocorrosion of Bi2S3 and improve photoreduction of aqueous Cr(VI) was developed via “dressed” a Cr(VI) imprinting polymer (Cr(VI)-IP) on urchin-like Bi2S3 (U-Bi2S3). Cr(VI)-IP wrapped on the three dimensional U-Bi2S3 was implemented by a bulk polymerization. The wrapped Cr(VI)-IP enabled to fast enrich and adsorb Cr(VI) on U-Bi2S3 leading to improve the photoreduced efficiency of photogenerated carriers and restrain the photogenerated electron-hole recombination. What’s more, Cr(VI)-IP wrapped on U-Bi2S3 was just like an “armor” which could support the three dimensional construction of U-Bi2S3 from the structural collapse of photocorrosion and retard the direct contact of oxygen and H2O from the surrounding media. As expected, the obtained U-Bi2S3@Cr(VI)-IP exhibited higher photostability, adsorption, photoreduction capacities towards the target Cr(VI) than the bare U-Bi2S3. The photocatalytic kinetic constant of U-Bi2S3@Cr(VI)-IP was 6 times higher than U-Bi2S3. After 3 times recycling uses, the morphology, crystal structure and chemical constitution of U-Bi2S3@Cr(VI)-IP were maintained. In addition, the removal efficiency of Cr(VI) by U-Bi2S3@Cr(VI)-IP was kept at 58% whereas U-Bi2S3 was almost lost to zero.