In-situ synthesis of TbAlO3/Tb3Al5O12/Tb2O3 three-component nanocomposite as a heterojunction photocatalyst with a green and eco-friendly approach

In-situ synthesis of TbAlO₃ (TAP)/Tb₃Al₅O₁₂ (TAG)/Tb₂O₃ three-component nanocomposite by sol–gel method using natural reactants and investigation of its photocatalytic activity can be considered eco-friendly aspects of this work. The bioactive components of natural compounds may play as a reductant and progress the process through auto-combustion sol–gel technique. It was found that Mulberry has more bioactive components than Capparis spinosa L., so nucleation overtook growth and produced finer particles with less agglomeration. Optical property studies represented a band gap at about 3.8 eV that is different from the amounts related to TAP and TAG. Hence, e^--h⁺ transfers in this nanocomposite were studied by estimation of energy levels of its constituents. According to findings, these components formed a UV-active photocatalyst with Type-I configuration to degrade organic pollutants. In other words, presence of Tb₂O₃ helped to benefit from properties of two ferroelectric compounds, that they have large band gaps, in photocatalytic reactions. After optimizing the photocatalytic parameters, maximum yield was obtained at about 94 %. Kinetics studies showed the photocatalytic process follows zero-order kinetics. In addition, the ^oOH was found as the most active promoter agent.