Facile preparation of CuO-Gd2Ti2O7 using Acmella uliginosa leaf extract for photocatalytic degradation of malachite green.

• CuO-Gd 2 Ti 2 O 7 has been successfully prepared by a two-phase system of hexane-water. • Optical bandgap of Gd 2 Ti 2 O 7 decreased from 3.68 to 1.78 eV after decoration with CuO. • Gd 2 Ti 2 O 7 actively work in the visible region. • CuO-Gd 2 Ti 2 O 7 exhibited the highest photocatalytic activity for MG degradation. CuO-Gd 2 Ti 2 O 7 has been prepared in a two-phase system of polar precursor solution and non-polar hexane fraction of Acmella uliginosa leaf extract (AUE). The secondary metabolites in AUE have an essential role in the synthesis of CuO-Gd 2 Ti 2 O 7. The optical bandgap value for CuO-Gd 2 Ti 2 O 7 plummeted from 3.68 to 1.78 eV, compared to Gd 2 Ti 2 O 7. The photocatalytic activity was investigated to degrade malachite green (MG) under visible light illumination. As a result, CuO-Gd 2 Ti 2 O 7 showed the MG degradation percentage of 88.60% after 90 min of illumination, which was 1.9 times higher than the MG degradation percentage over Gd 2 Ti 2 O 7. The improved photocatalytic activity could be ascribed to the narrower optical bandgap Gd 2 Ti 2 O 7 after being decorated by CuO, which effectively works in the visible region. This research suggests a novel method to prepare CuO-Gd 2 Ti 2 O 7 as a promising candidate with good photocatalytic activity for the degradation of malachite green under visible light illumination. [Display omitted] [ABSTRACT FROM AUTHOR]