Efficient pollutant degradation under ultraviolet to near-infrared light irradiation and dark condition using CuSe nanosheets: Mechanistic insight into degradation

The hydrothermally prepared two-dimensional copper selenide nanosheets (2D CuSe NSs) have been employed for the first time to degrade rhodamine B (RhB) in the presence of hydrogen peroxide (H 2 O 2 ) under ultraviolet to near-infrared (NIR) light irradiation and dark condition. The experimental measurements demonstrate that 99.7% RhB is degraded under NIR light irradiation for 120 min. Moreover, the experimental tests clearly demonstrate that the 2D CuSe NSs display excellent ability to degrade RhB under dark condition. The different degradation mechanisms under the light irradiation and dark condition have been revealed by the experimental tests through the investigation of H 2 O 2 role and the evaluation of hydroxyl radicals (•OH) and H 2 O 2 concentration during the degradation reaction. Under light irradiation, the H 2 O 2 traps the photogenerated electrons of the CuSe to generate •OH and hydroxide ion (OH − ), and the holes react with OH − to produce •OH, making RhB to be degraded efficiently. Under dark conduction, the 2D CuSe NSs react with H 2 O 2 to exhibit Fenton-like process to degrade RhB with a degradation rate of 90.0% within 120 min. This work opens a pathway for developing nanostructures with full-solar-responsive and strong near-infrared photocatalytic activity as well as Fenton-like reaction to efficiently degrade pollutants under light irradiation and dark condition.