Green Synthesized Cu2O-Cu(OH)2@Cu Nanocomposites with Fenton-like Catalytic Properties for the Degradation of Cationic and Anionic Dyes

Abstract

In this work, we introduce an environmental and sustainable approach to grow free standing heterogeneous Cu2O-Cu(OH)2 nanocomposites on a Cu mesh using spinach leaf extract and glycerol. Structural characterizations for samples annealed at 200 °C revealed that there is more Cu(OH)2 than Cu2O on the mesh surface. The photocatalytic activity of the green synthesized catalyst was studied for degradation of a cationic dye methylene blue (MB), an anionic dye methyl orange (MO) and a mixture of both dyes. The effect of changing the dye’s initial pH value on the photodegradation process was explored. After 40 min of irradiation under sunlight, with a maximum intensity of 5 mW/cm2, a basic MB dye (pH-11) showed about 80% color removal with an average kinetic rate of 94.5 m·min−1. In contrast, 93% of the acidified MO dye (pH-2) was degraded with an average kinetic rate of 126.5 m·min−1. Moreover, the versatility of the Cu2O-Cu(OH)2@Cu mesh was evaluated using a remarkable selective separability for a mixture of MB and MO at pH = 2, in the dark and under normal sunlight. Such promising outcomes indicate the potential of our green composites to degrade dyes as both photocatalysts under daylight and as Fenton-like catalysts in darkness.