Designing Z-scheme AgIO4 nanorod embedded with Bi2S3 nanoflakes for expeditious visible light photodegradation of congo red and rhodamine B

Abstract

The present study describes the enhanced photodegradation of organic pollutant dyes, congo red (CR) and rhodamine B (RhB) dyes under visible light irradiation. AgIO4 nanorods decorated on Bi2S3 nanoflakes in various proportions were synthesized via sono-chemical route wherein the deposition of varying amounts of AgIO4 on Bi2S3 plays a pivotal role in improving the photodegradation ability. The characterization of the as-synthesized nanohybrids was assessed by XRD, UV–vis DRS, PL, EIS, ESR, FT-IR, XPS, HR-TEM, FE-SEM, N2 adsorption and desorption techniques. The effect of initial CR and RhB dye concentration, reaction pH and usage of nanohybrid concentration were investigated where 30%-AgIO4/Bi2S3 exhibited excellent visible light photodegradation of 95.58% for CR and 96.11% for RhB dyes at 140 min and 100 min respectively. The superoxide (•O2−) and hydroxyl radicals (•OH) played predominant role in the photodegradation of CR and RhB which is experimentally confirmed by radical trapping experiments. Also, the photocatalysts exhibited good photo stability and excellent reusability. The TOC analysis confirmed the complete mineralization of CR and RhB dyes by the nanohybrid and the formation of possible intermediate and degradation pathway was delineated based on GC/MS analysis. The outstanding photodegradation performance were ascribed to the Z-scheme charge transfer path, which effectively promotes the separation and transfer of e−/h+ pairs, resulting in a strong redox activity of the accumulated charge to decompose organic dyes during the degradation reaction. The study suggested that the nanohybrid can be utilized for the removal of organic pollutants from the contaminated water bodies.