Synthesis, characterization and photocatalytic dye degradation studies of novel defect pyrochlore, KHf0.5Te1.5O6

Abstract

We report the solid-state synthesis of KHf_0.5Te_1.5O₆ (KHTO), its characterization and employment as photocatalyst for methylene blue and methyl violet degradations in aqueous solution. The material was subjected to X-ray Diffraction (XRD), Field emission-scanning electron microscopy (FE-SEM), Energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), N₂ adsorption/desorption and XPS measurements. The material was crystallized in a cubic lattice with the   space group. The bandgap energy of the KHTO is 2.60 eV. The photocatalytic methylene blue (MB) and methyl violet (MV) dyes degradation efficiency of KHTO was investigated under the visible light irradiation. The mechanistic dye degradation pathway of MB was studied. The radical quenching experiments reveal that the short-lived species O₂^●-, OH^●, and h⁺ actively participate in the degradation of MV and MB dyes. An additional terephthalic acid experiment was carried out to establish the participation of OH^● radicals in the dye degradation process. The stability and reusability of the KHTO catalyst were also studied.