Cost effective synthesis of CuxBi2-xSe3 photocatalysts by sol-gel method and their enhanced photodegradation and antibacterial activities

Abstract

A simple sol-gel approach was used to synthesize Cu doped Bismuth Selenide nanoparticles denoted as CuxBi2-xSe3 (x = 0.1, 0.2), in order to comprehend the effect of Cu-dopant on the photocatalytic and antibacterial activity of Bismuth Selenide. The structural properties of prepared samples were investigated by the XRD technique and results showed the formation of hexagonal CuxBi2-xSe3 (x = 0.1, 0.2). The average crystallite size of CuxBi2-xSe3 was found to increase from 39 nm to 42 nm with the increase in the concentration of Cu ions. Atomic force microscopy (AFM) was used to confirm the morphology and particle size of prepared samples. Photoluminescence (PL) studies revealed the decrease in band gap from 1.66 eV to 1.61 eV for Cu0.1Bi1.9Se3 and Cu0.2Bi1.8Se3, respectively. The Raman spectra of CuxBi2-xSe3 (x = 0.1, 0.2) showed two vibrational modes at 130 cm−1 and 170 cm−1. The photocatalytic performance of prepared nanoparticles was evaluated by the removal of methyl blue (MB) and malachite green (MG), under natural sunlight. Cu doped Bismuth Selenide Cu0.2Bi1.8Se3 exhibited higher photocatalytic activity as compared to Cu0.1Bi1.9Se3 and undoped Bismuth Selenide with the 97% and 99% degradation of MB and MG, respectively. Hence, Cu doping proved an efficient way to enhance the photocatalytic response of Bismuth Selenide. Through the antibacterial activity, it was further disclosed that the Cu doped samples had better inhibition zones than undoped Bismuth Selenide. The maximum inhibition zone (29 mm) was observed at optimum doping concentration for Cu0.2Bi1.8Se3. From the results, it can be deduced that Cu0.2Bi1.8Se3 can be as effective photocatalytic and antibacterial agent to treat water pollution.