Sol-gel auto-combustion synthesis of a novel chitosan/Ho2Ti2O7 nanocomposite and its characterization for photocatalytic degradation of organic pollutant in wastewater under visible illumination

In the last few years, the release of toxic contaminants into the ecosystem has expanded dramatically. Hence, multiple photocatalysts have been improved for the elimination of toxic contamination. The manufacture of photocatalysts based on nanostructures is a promising strategy to improve photocatalytic potential. In this regard, Ho2Ti2O7 and chitosan-coated Ho2Ti2O7 nanocomposites have been manufactured through a facile auto- combustion and co-precipitation route. Diverse factors, including calcination temperature, type of precursor of titanium, solvent, and types of fuels, can affect the structure, purity, morphology, and particle size of samples. Ho2Ti2O7 nanostructures are a good candidate for photocatalytic evolution owing to their adequate bandgap (2.5 eV) in the visible region. This is the first study of the photocatalytic efficacy of Ho2Ti2O7 and chitosan-coated Ho2Ti2O7 nanocomposites. Their photocatalytic performance was explored over several dyes as pollutants, including malachite green, methyl violet, eriochrome black T, methy- lene blue, acid red 198, methyl orange, and thymol blue under visible radiation. Besides, diverse parameters, such as Ho2Ti2O7 contents, dye levels, were studied on the efficiency of the reaction. The results demonstrated that the maximum efficiency of Ho2Ti2O7 and its chitosan-coated was perceived over malachite green with degradation percentages of 95.7 and 79.9%, respectively. Ho2Ti2O7 nanostructures were highly stable due to their recycla- bility test and kept their photocatalytic potential over five cycles. The decrease in photo- catalytic efficiency in the 5th period is 7.1%. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.