Sensitization of narrow band gap Bi2S3 hierarchical nanostructures with polyaniline for its enhanced visible-light photocatalytic performance

Hierarchical nanostructures of bismuth sulfide (Bi2S3) have been synthesized in orthorhombic phase by hydrothermal method. Conducting polymer polyaniline (PANI) has been synthesized by the chemical oxidative polymerization method and further coupled with Bi2S3 in various weight percentages (1, 2, 5, and 10 wt%) of PANI/Bi2S3 nanocomposite by chemisorption method. The potentiality of these prepared nanostructures has been investigated for the photodegradation of methylene blue (MB) aqueous solutions. Among all, PANI/Bi2S3 (5 wt%) nanocomposite displayed the highest photodegradation efficiency. An similar to 9-fold augment in the photocatalytic activity of bismuth sulfide has been found after its incorporation in PANI matrix. This enhancement is ascribed to the formation of staggered heterojunction and interfacial sites between PANI and Bi2S3 that suppressed recombination of photogenerated charge carriers leading to quicker deterioration of MB. The mechanism for the photocatalytic degradation of methylene blue has been proposed. Based on our results, it is suggested that the coupling of conducting polymer with metal chalcogenides is an important approach for solving the environmental remediation challenge.