Novel High Efficiency Layered Oxide Photocatalyst Li2SnO3 for Rhodamine B and Tetracycline Degradation

Abstract

The use of a layered Li2SnO3 material as an efficient photocatalyst for the degradation of environmental pollutants (Rhodamine B and tetracycline) was investigated. The structure and morphology of the material were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. Optical measurements demonstrated that Li2SnO3 was a UV-light-responsive material with a band gap of 3.71 eV. The maximum kinetic rate constants of photocatalytic degradation of Rhodamine B and tetracycline solutions were 0.0155 min−1 and 0.0406 min−1 · L/mg, respectively, when exposed to UV-light irradiation within 120 min. Trapping experiments demonstrated that holes ( h + ) , hydroxyl radical ( · O H ) and superoxide radical ( · O 2 − ) were the dominant active species during the degradation of Rhodamine B and tetracycline. Theoretical band structure calculations revealed that Li2SnO3 was a direct gap semiconductor with a large m h * / m e * value (4.7) near the band edge. Partial charge density near the top of the valence band indicated that the photocatalytic oxidation reaction occurred largely on the O-2p states. The excellent photocatalytic performance was attributed to the synergistic effect of the layered crystal structure and large m h * / m e * . This work represents an important contribution to the design and optimization of efficient oxide photocatalysts with layered crystal structures for environmental remediation.