Effect of Composition Variation on The Crystal Size and Band Gap of Thin Film Nano Photocatalyst Fe₂O₃/CuO/MnO₂

Abstract Commercial activities in the field of laundry services, cause problems in the water environment, hurt air quality, and were dangerous for life. Efforts that are now the leading option for most people are using photocatalyst technology on semiconductor materials. MnO 2 semiconductor is used as an auxiliary component for the development of CuO-Fe 2 O 3 photocatalyst to increase the level of degradation of organic contaminants in the environment. This study aimed to determine the crystal size and band gap of Fe 2 O 3 /CuO/MnO 2 nanocomposite. This type of research is a laboratory experiment, and the characterization tools used include X-Ray Diffraction and Uv-Vis Spectrophotometer. Synthesis of Fe 2 O 3 /CuO/MnO 2 nanocomposite with various compositions of Fe 2 O 3 /CuO/MnO 2 respectively, 0.9:2.9:1, 1:3:0.8, 1.1:3.1:0.6, 1, 2:3.2:0.4, and 1.3:3.3:0.2 with the sol-gel method has been successful. Thin layer growth was carried out by the spin coating method with a sintering temperature of 400° C. This research results show that composition variation affects the crystal size and band gap of Fe 2 O 3 /CuO/MnO 2 nanocomposite. The crystal sizes of the nanocomposites obtained were 25.18 nm, 24.48 nm, 25.55 nm, 23.57 nm, and 27.52 nm. The band gap energy values of the nanocomposites were 1.55 eV, 1.44 eV, 1.44 eV, 1.45 eV, and 1.46 eV.