Structural, compositional study, and thermal behavior of TiO2/Cr2O3/GO nanocomposite for methylene blue degradation

Abstract

This study emphasizes the methylene blue (MB) dye degradation potential of mixed systems of TiO2, Cr2O3, and graphene oxide (GO) based nanocomposites (NCs). Structural and thermal studies for TiO2, Cr2O3, TiO2/GO, Cr2O3/GO, TiO2/Cr2O3, and TiO2/Cr2O3/GO compositions are executed. XRD, FTIR, and EDX confirm the lack of impurities within compositions. Additionally, the EDX, and FTIR results are agreeing with each other in highly oxygenated NC formation. Regarding the morphological study, TEM micro-graphing supports TNC formation owing to aggregation-growing inhibition that causes surface area widening and enhances dye removal potential. On the other hand, FESEM is agreeing with TEM that TNC shows a lowering in grains size and aggregations that TiO2, and Cr2O3 record 60, and 75 nm, respectively. This agreement with TEM, and FESEM in widening surface area and adding crystallinity defects raising which recommended the occurrence of chemical decontamination operation. The thermodynamic study reports almost equal values of enthalpy (ΔH) and activation energy (i.e. according to the CR model: 155.6, 147.7 KJ mole−1, respectively), this is explained by the presence of TNC in the condensed phase through the temperature scope (545–750 °C), besides its significant stability. Moreover, the EDX, and FTIR results are agreeing TiO2/Cr2O3NC shows intermediate thermal behavior between its pure ingredient, leaving 97.3 % as a residual. TNC total weight loss hits 9.2 %. This percentage is contributed to four stages, 1.3 % (30–300 °C/dehydration), 2.3 % (300–545 °C/structure rearrangement), 3.5 % (545–750 °C/GO reduction process & structure rearrangement), and 2.1 % (750–100 °C/GO reduction). The inorganic compositions show acceptable thermal stability for environmental usage. The stated NCs able to be recycled that TiO2/Cr2O3/GO shows a minor decline in MB degradation potential that decreases from 98.8 to 87.5 % after five cycles.