Correction to: Efficient photocatalytic activity of Mo-doped ZnO-In₂O₃ type-II staggered heterostructure for dye degradation

Correction to: International Journal of Environmental Science and Technology https://doi.org/10.1007/s13762-023-05292-y

The original version of this article unfortunately in place of experimental section contains both sections, material and methods as well as experimental section. Page 4 of original version Experimental section heading and the text until material and method need to be removed.

Materials and methods

Materials

ZnO powder was purchased from SIGMA ALDRICH, and In₂O₃ powder was bought from Alfa products. All the materials were used without further purification.

Fabrication of ZnO:Mo/In₂O₃:Mo heterostructure

Thin films of ZnO:Mo, In₂O₃:Mo and their heterostructure were fabricated via layer-by-layer deposition using thermal evaporation method onto glass substrate. Prior to the film formation, standard substrate cleaning method was adopted where the glass substrate was ultrasonicated for 15 min in acetone, isopropyl alcohol (IPA) and DI water, respectively, to make sure that all the containments are completely removed. For the deposition of film, a thermal evaporator has been used at 2 × 10⁻⁵ Torr. ZnO thin films were grown from ZnO powder (SIGMA ALDRICH, 99.9%) where ZnO powder was placed in a tungsten boat and current was ramped up to a value of 180 A to produce heat required for the evaporation of ZnO powder, whereas the chamber and the substrate were held at room temperature (25 °C). The growth of ZnO thin films was carried out for 15 min using thermal evaporator to achieve the films of thickness ranging from 50 to 70 nm, which was further annealed for 1 h at 550 °C in a tube furnace. The annealing environment contained Mo so that during annealing Mo doping can be achieved along with better crystallinity of thin films. For the deposition of In₂O₃ film, In₂O₃ powder (Alfa products, 99.95%) was used for thermal evaporation and the abovementioned procedure was followed. After deposition of In₂O₃ thin films, they were annealed further for 1 h at 550 °C in a tube furnace in the Mo environment. For the deposition of ZnO:Mo/In₂O₃:Mo heterostructure, In₂O₃ thin films were subsequently deposited on the pre-deposited ZnO:Mo thin film, to form ZnO:Mo /In₂O₃:Mo heterostructure, all the other parameters remained constant, and this heterostructure was further annealed at 550 °C for 1 h in a tube furnace under Mo environment to dope In₂O₃ with Mo as well.

Photocatalysis setup

The photocatalytic efficiency of thin-film heterostructure was determined in a solution containing 1 × 10⁻⁵ M MB dye made in DI water by serial dilution. 0.1 gm of MB dye was dissolved in 30 ml of DI water to make 1 × 10⁻² M solution of MB, then 3 ml of this solution was taken and further dissolved in 27 ml of DI water to make 1 × 10⁻³ M solution. This procedure was further carried out twice to get 1 × 10⁻⁵ M of MB. Figure 1 shows the schematic of photocatalysis setup, thin films were dipped into 30 ml of this diluted solution, and the setup was then placed under the sunlight for 4 consecutive hours between 11 a.m. to 3 p.m. (longitude: 27.2046°N, latitude: 77.4977°E). After every 1 h, 3–4 ml of this solution was taken out from the beaker and UV–Vis spectroscopy was done to check the concentration of MB in the solution after every hour.

Fig. 1

Schematic of photocatalysis setup

Original article updated.