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

1092-1099In this study, KHf0.5Te1.5O6 (KHTO) semiconductor has been synthesized by the solid-state method. The synthesized material is characterized using X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible diffuse reflectance spectroscopy, field emission-scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption/desorption measurements. The material is found to be crystallized in a cubic lattice with the space group Fdm . The bandgap energy of the KHTO is 2.6 eV. The photocatalytic activity of KHTO has been investigated by measuring the degradation of methylene blue (MB) and methyl violet (MV) dyes under the visible light irradiation. The mechanistic dye degradation pathway of MB has been studied. The radical quenching experiments reveal that the short-lived species O2●-, OH●, and h+ actively participate in the degradation of MB and MV dyes. An additional terephthalic acid experiment has been carried out to establish the participation of OH● radicals in the dye degradation. The stability and reusability of the KHTO catalyst are also studied

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

We report the solid-state synthesis of KHf0.5Te1.5O6 (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

Transition metal ion (Ni2+, Cu2+ and Zn2+) doped defect pyrochlore, KTaTeO6: Synthesis, characterization and photocatalytic studies

One of the strategies to decrease the bandgap energy and increase the optical absorption ofthe catalysts is to dope with transition metal ions. In this paper, the results obtained for thedegradation of methylene blue (MB) pollutant in the presence of M2+ (M = Ni, Cu, and Zn) doped KTaTeO6 (here after abbreviated as M-KTTO) upon visible light irradiation are presented.The parent KTaTeO6 and the M2+ (M = Ni, Cu, and Zn) doped KTaTeO6 were prepared by solidstate and ion-exchange methods, respectively. All the samples were characterized by XRD,SEM/EDX, FT-IR, UV-Vis DRS, XPS, and PL techniques. The metal ion doping in place of K+has influenced the electronic and optical properties considerably. The doping of M2+ into KTTOlattice has narrowed the bandgap energy, increased the visible light absorbance leading to higherphotocatalytic activity. The M-KTTO materials show higher photocatalytic activity compared toparent KTTO, in particularly Cu-KTTO. The scavenging experiments indicate that •OH radicalsare the main active species involved in the photodegradation of MB. The Cu-KTTO ischemically stable and can be used at least up to five cycles. The mechanistic pathway of MBdegradation was proposed over Cu-KTTO