Synthesis and characterization of a novel single-phase sputtered Cu2O thin films: Structural, antibacterial activity and photocatalytic degradation of methylene blue

Abstract Methylene blue (MB) is a commonly found refractory pollutant in textile wastewater. Herein cupric oxide (Cu2O) thin films have been discussed as a subject of great interest for their potential use in degradation of MB from wastewater. To enhance MB removal; Cu2O thin films were deposited using DC magnetron sputtering at different substrate temperatures ranging between 25 and 300 °C. The Cu2O thin films prepared at the substrate temperature of 200 °C (Cu2O@200 °C) exhibited the 100% photocatalytic degradation of MB from wastewater. Kinetic modelling data indicated that R2 values for pseudo-first order equation (0.95–0.96) was higher than pseudo-second equation (0.88–0.94) suggesting that chemisorption mechanism was dominant for MB adsorption by all four types of Cu2O thin films. This enhanced MB degradation was attributed to its crystalline structure, optical band gap, and surface defects. The structural analysis confirmed the crystalline single-phase thin films of Cu2O prepared at varying substrate temperatures. The change in chemical composition and chemical analysis was carried out through x-ray photoelectron spectroscopy that showed the presence of octahedral and tetrahedral coordination of Cu2+. The antibacterial activity of the sputtered coated Cu2O thin films exhibited considerable behaviour against Escherichia coli, accordingly creating a possibility of its application in technological fields like the touch screen appliances. The present study not only offered a healthful alternative to traditionally used ultraviolet based wastewater treatment technologies but also introduced an auto-response methodology to reduce the rate of microbial contamination on a lot of different surfaces.