Ba2−xHoxSr2−yNiyFe12O22 and its composite with MXene: synthesis, characterization and enhanced visible light mediated photocatalytic activity for colored dye and pesticide

Abstract

The rapid recombination of charges of photogenerated electrons and holes severely limits single semiconductor photocatalytic applications. In this study, a simple and facile sol–gel approach was used to synthesize Ba_2−xHo_xSr_2−yNi_yFe₁₂O₂₂ (x = 0, 0.1 and y = 0, 0.5). The composite of holmium–nickel doped barium–strontium ferrite with MXene (Ba_1.9Ho_0.1Sr_1.5Ni_0.5Fe₁₂O₂₂@MXene) was synthesized by ultrasonication method. These synthesized samples were subsequently used to photodegrade rhodamine B (RhB) and pendimethalin under visible light illumination. The results of the experiments demonstrated that MXene, as a cocatalyst, considerably reduces the rate of recombination of charges and broadens absorption of visible light by providing increased surface functional groups to improve the photocatalytic activity of synthesized samples. MXene is thermally stable, have high electrical conductivity, have adjustable bandgap, and hydrophilic in nature. The optimized Ba_1.9Ho_0.1Sr_1.5Ni_0.5Fe₁₂O₂₂@MXene composite demonstrated an excellent photocatalytic rate by degrading 78.88% RhB and 75.59% pendimethalin in 140 minutes. Moreover, the scavenging experiment revealed that photogenerated electrons and holes were the primary active species involved in RhB and pendimethalin photodegradation, respectively. Ba_1.9Ho_0.1Sr_1.5Ni_0.5Fe₁₂O₂₂@MXene showed increased photocatalytic behavior because it has increased surface area which decreases rate of recombination of electron and hole pair, hence photocatalytic activity increases. It is observed that Ba_1.9Ho_0.1Sr_1.5Ni_0.5Fe₁₂O₂₂@MXene has potential application in photocatalytic degradation of harmful pollutants.