Visible light active SiC/Bi2WO6/CD heterojunction: Fabrication, characterization, and optimization of its photocatalytic activity toward hematoxylin

Abstract

The dye removal from water supplies is an imperative issue because of its adverse effects on human health. Compared with other expensive removal techniques, photocatalytic degradation is a cost-effective and eco-friendly pathway. Here, a simple developed method was applied to fabricate a heterojunction composite photocatalyst composed of SiC/Bi₂WO₆/CD. Moreover, a comprehensive assessment of the synthesized composites’ structural and morphological properties was conducted using various analytical methods. X-ray diffraction (XRD) revealed a crystallite size of 18.4 nm for SiC, 26.5 nm for Bi₂WO₆, 17.0 nm for CD, and 18.1 nm for SiC/Bi₂WO₆/CD. An SEM image showed heterogeneous surfaces with irregular-sized particles, possibly due to agglomeration of particles at the surface of SiC/Bi₂WO₆/CD. There is also a band gap of 2.21 for this composite. To evaluate its boosted visible-light catalytic performance toward hematoxylin (HTX), the experimental design by the RSM was applied by examining experimental variables, including the SiC/Bi₂WO₆/CD dosage, the CTX concentration, the duration of light illumination, and temperature. Accordingly, ANOVA analysis was performed to confirm the model goodness and the significance of the variables selected. The pseudo-first-order kinetic rate constant of the photocatalytic process was about 0.042 min⁻¹. Based on the results of the scavenging experiments, superoxide radicals and photogenerated holes are more vital reactive species in HTX photodegradation. The ternary photocatalyst showed good stability after four reusing runs. The highly effective and sustainable approach for the dye removal from water, and some insights about the structural features and probable practical uses of a novel catalyst are introduced here, which proves the critical potential of the novel photocatalyst composite and broadening the scope of visible light-responsive heterojunction photocatalysts.