Photodegradation of rhodamine B-dye pollutant using CaCu3Ti4O12-multiwall carbon nanotube nanocomposites

Abstract

A unique CaCu3Ti4O12-Multiwall carbon nanotube (MWCNT) nanocomposite was produced using a two-step ultrasonic and mixing method. In this study, the effects of MWCNT (0, 0.1,0.2, and 0.3 wt%) on the structural, morphological, optical and photocatalytic properties of CaCu3Ti4O12 were investigated using the following methods: XRD, FTIR, HRTEM-EDAX, FESEM, BET surface area, UV–vis, and photodegradation of Rhodamine B (RhB) dye under UV and visible irradiation illumination. Morphology characterization showed that CaCu3Ti4O12 with particle sizes of about 180 nm and MWCNT with outer diameters of about 10 nm were mixed perfectly. With MWCNT addition, the crystallite size declined (from 44 nm to 32 nm) whereas the surface area increased (from 1.22 m2g−1 to 11.00 m2g−1) along with a decrease in optical bandgap energy (from 3.5 eV to 3.0 eV), which is very promising for utilization as a photocatalyst in environmental applications. The CaCu3Ti4O12 coupled with 0.3 wt% of MWCNT yielded the highest photodegradation efficiencies (η%) i.e. 85.65% and 82.92% in 30 min of UV and visible light illumination, respectively. The photocatalyst displayed good repeatability performance; this was proven as it attained 80.50% and 78.62% of η% after five cycles under UV and visible light, respectively. The kinetic data were fitted to pseudo-first-order model for all the samples with rate constants of 0.027 min−1and 0.26 min−1, respectively. The current work paves the way towards understanding how to effectively enhance the photocatalytic performance of CaCu3Ti4O12 using MWCNT.