Hydrothermally synthesized Gd-doped BiSbO4 nanoparticles and their graphene-based composite: A novel photocatalytic material

Abstract

Developing and fabricating highly effective semiconducting photocatalysts for wastewater treatment is a promising approach to dealing with environmental sustainability concerns. Bismuth antimony (BiSbO4) has gained considerable interest as a photocatalyst for water remediation applications. On the other hand, poor charge separation, slower charge transfer, rapid electron-hole pair recombination, and a wider bandgap severely limit its practical applications. Herein, novel rare-earth (Gd3+) doped BiSbO4 nanoparticles were fabricated via a facile hydrothermal approach, and these nanoparticles were anchored on 2D reduced graphene oxide (rGO) nanosheets to form nanocomposite (rGO/Gd-BiSbO4) to remove toxic pollutants from industrial effluents. We investigated the photocatalytic performance of fabricated rGO/Gd-BiSbO4 nanocomposites compared with Gd-BiSbO4 and pure BiSbO4 under visible light irradiation, which removes Methylene Blue (MB) organic dye. Compared with pristine BiSbO4 and Gd-BiSbO4 photocatalysts, the rGO-based Gd-BiSbO4 nanocomposite exhibited notably higher photocatalytic activity for degrading MB dye. Statistically, after 70 ​min of illumination under visible light, the nude BiSbO4, Gd-BiSbO4, and rGO/Gd-BiSbO4 photocatalysts degraded approximately 47.1%, 58.4%, and 95.6% of the dye in an aqueous solution, respectively. The kinetic studies showed that the rGO supported Gd-BiSbO4 photocatalyst removed the MB dye at a rate constant (k) of 0.0295 min-1, which was 2.54-fold and 3.39-fold greater than Gd-BiSbO4 (k ​= ​0.0116 min-1), and BiSbO4 (k ​= ​0.0087 min-1), correspondingly. The enhanced photocatalytic efficiency of the rGO/Gd-BiSbO4 nanocomposite is primarily due to its robust and unique structure, which is a result of the synergetic effects of the highly conducting rGO matrix and the Gd3+ ion. The rGO nanosheets promote the faster migration of photoinduced electrons and suppress electron-hole pair recombination in this nanocomposite structure. These nanosheets act as an efficient cocatalyst to provide more adsorption sites for MB molecules and accelerate the dye degradation process. The current study paves the way to developing a versatile, economical, and highly efficient rGO/Gd-BiSbO4 photocatalyst for removing organic pollutants found in industrial waste.