CaTiO<sub>3</sub> Nanocuboids Decorated with Bi<sub>2</sub>WO<sub>6</sub> Nanoflakes for Stimulating Exciton Dissociation in Photocatalytic Dye Degradation
Kaushalya Bhakar, Soumya Roy, Naresh A. Rajpurohit, Dinesh Kumar
Abstract
Herein, we tailored a Bi 2 WO 6 –CaTiO 3 (BWO–CTO) nanostructure for the effective degradation of various textile dyes such as rhodamine B (RhB), methylene blue (MB), methyl orange (MO), and Congo red (CR), under visible light. The nanostructures were developed using a simple hydrothermal method and characterized using XRD, FTIR, FE-SEM, HR-TEM, XPS, PL, EIS, and Mott–Schottky analysis. Different nanostructures were developed with varying BWO to CTO mass ratios (5, 10, 15, and 20%), denoted as 5BWO-CTO, 10BWO-CTO, 15BWO-CTO, and 20BWO-CTO, respectively. The 15BWO-CTO heterostructure exhibits excellent photocatalytic activity with a degradation efficiency of 98.5, 97, 84, and 74% for RhB, MB, MO, and CR, respectively, within 60 min of irradiation. The appropriate band alignment of the BWO-CTO heterojunction efficiently suppresses the dissociation of excitons and extends their lifespans. The built-in electric field allows the movement of charge carriers from BWO to CTO, following the Z -scheme charge transfer mechanism with high redox capacity. The kinetic study indicates a pseudo-first-order model with a higher reaction rate for 15BWO-CTO (0.0691 min –1 ), good cyclic stability up to four cycles, and high energy efficiency (927 kW h/m 3 ). The findings affirm the prowess of the BWO–CTO heterostructure as a potent photocatalyst for targeted dye degradation. The TOC and LCMS analyses were performed to evaluate the mineralization and possible degradation pathways for RhB dye.