Fabrication of visible-light-driven photocatalysts based on Nd-doped Zn₂SnO₄ semiconductor and carbonous nanomaterials

The main aim of this research was to sensitize the Zn₂SnO₄ spinel-like photocatalyst to solar light to degrade the organic pollutants in aquatic media. For this purpose, firstly, the N-doped Zn₂SnO₄ (N = Nd, Er, and Gd) was synthesized using the facile hydrothermal method to evaluate the effect of the Nd³⁺, Er³⁺, and Gd³⁺ ions as dopant on the photocatalytic activity of the Zn₂SnO₄. The Nd³⁺ ions with a content of 5% were selected as the optimum dopant, which efficiently narrowed the band gap of the Zn₂SnO₄ from 3.5 eV to 2.70 eV. Afterward, the effect of the carbonous supports including, graphene oxide (GO), graphitic carbon nitride (g-C₃N₄), and functionalized single-walled carbon nanotube (f-SWCNT) on the photocatalytic activity of the undoped and Nd-doped Zn₂SnO₄ were investigated. The synthesized photocatalysts were characterized using diverse techniques. Based on the results, the degradation efficiency of the AR14 was remarkably increased from 21.9% for Zn₂SnO₄ to 87.41% for Nd-doped Zn₂SnO₄ under xenon light within 90 min of reaction time. Moreover, the highest degradation efficiency of 99.6%, 99.6%, and 96.3% was obtained within 90 min of reaction time under xenon light by hybridizing the Nd-doped Zn₂SnO₄ with g-C₃N₄, GO, and f-SWCNT, respectively.