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.

Automated summary

By coating a Cr(VI) imprinting polymer on 3D Bi2S3 structure, the photocorrosion of Bi2S3 was reduced and the photoreduction efficiency of Cr(VI) was improved. The coating acted as an armor to protect Bi2S3 from structural collapse and external erosion.