Effect of Ag+, Cu2+ and Sn2+ Doping on Structural, Optical and Photocatalytic Properties of KGe0.5Te1.5O6 with Defect Pyrochlore Structure

Abstract Defect pyrochlore‐type oxide, KGe 0.5 Te 1.5 O 6 (KGTO) and its Ag + , Cu 2+ and Sn 2+ doped compositions were prepared by solid state and ion‐exchange methods respectively. The XRD results suggest that both parent KGTO and Ag + , Cu 2+ and Sn 2+ doped KGTO have crystallized in cubic lattice. The morphology of all compositions was obtained from SEM‐EDS and TEM‐SAED measurements. The textural properties were obtained from N 2 adsorption‐desorption measurements. The FT‐IR and Raman spectra of all compositions are comparable. Surface elemental composition and electron‐hole recombination rate were deduced from XPS and PL measurements respectively. The photocatalytic performance of these materials was tested in the degradation of methylene blue (MB) and methyl orange (MO) dyes. The doping of Ag + , Cu 2+ and Sn 2+ into the KGTO lattice improved optical characteristics and photocatalytic activity significantly. Among the compositions investigated, Sn‐KGTO shown highest photocatalytic performance with 82 % for MB and 67 % for MO in 180 min. Trapping experiments were conducted to identify the active species participated in the MB degradation over Sn‐KGTO. The generation and participation of ⋅OH and O 2 − ⋅ radicals were studied by terephthalic acid and potassium bromate experiments respectively. The reusability and chemical stability of Sn‐KGTO against MB degradation were also examined. A possible reaction mechanism was proposed to understand the MB degradation in the presence of Sn‐KGTO.