Ru doping effect on the structural, electronic, transport, optical and dye degradation properties of layered Li2MnO3

Abstract

Ru doped Li 2 MnO 3 compositions show the presence of redox couples Mn +3-Mn +4 and Ru +4-Ru +5. Due to the presence of these redox couples in Li 2 Mn 1−x Ru x O 3 (x = 0.05, 0.1), Ru doped compositions show (i) change in structure (ii) large decrease in impedance(~ 10 7 to ~ 10 5 Ohm) (iii) degrade methyl orange and methylene blue solution (pH-6) in quick time in presence of tungsten (W) bulb and sun light. Synchrotron X-ray powder diffraction studies show the change in lattice parameters with Ru doping at Mn site in Li 2 Mn 1−x Ru x O 3 (x = 0.05, 0.1). Raman and Infrared spectroscopic studies show the shift in Mn-O stretching mode of Li 2 MnO 3 towards lower wave number with Ru doping. Soft X-ray absorption spectroscopic studies show the presence of mixed valences of Mn +3 , Mn +4 , Ru +4 and Ru +5 in Li 2 Mn 1−x Ru x O 3 (x = 0.05, 0.1) using L 2,3 and M 4 edge. UV-Vis diffuse reflectance spectroscopic studies show the optical band gap in visible light range in Ru doped Li 2 Mn 1−x Ru x O 3 (x = 0.05, 0.1) compositions. The presence of 5 mg of Li 2 Mn 0.9 Ru 0.1 O 3 degrades 5 ml of methyl orange solution (10 mg/L) of pH 6 in 5 min and methylene blue solution (10 mg/L) of pH 6 in 3 min of exposure in W bulb light.

Reaction Mechanism of Li2MnO3 Electrodes in an All-Solid-State Thin-Film Battery Analyzed by Operando Hard X-ray Photoelectron Spectroscopy

“…A previous study used the addition of U on O 44 to obtain a computational bandgap of O3−Li 2 MnO 3 that was close to the experimental one. The calculated minimum and direct bandgaps of Li 2 MnO 3 in our implementation are 2.02 and 2.03 eV, which is consistent with experimentally obtained bandgaps of 2.1, 46 2.17, 47 1.76 (nanoparticle), 48 and 2.47 eV (alternative stacking). 49 The plane-wave cutoff was 550 eV, a 3 × 5 × 4 k-mesh was used, and the convergence criteria for the structural relaxations were total energy change less than 10 −6 eV and norms of all the forces less than 0.01 eV/Å.…”

Structural, optical, microstructure, and giant dielectric behavior of parent, Cu and Sr doped La0.55Li0.35TiO3‐δ

“…This is assigned to the defects created in the structure of the compositions which arises from disruption of the symmetry of TiO 6 octahedron as an inference of cation substitution 37–38 . Doping of foreign atoms at different lattice sites change the band gap value of materials due to the movement of electrons from valence band to conduction band 37–40 . The energy band gap value depends on the degree of orderness or disorderness in the structure of the material.…”

“…[37][38] Doping of foreign atoms at different lattice sites change the band gap value of materials due to the movement of electrons from valence band to conduction band. [37][38][39][40] The energy band gap value depends on the degree of orderness or disorderness in the structure of the material. The increase in the value of energy band gap is accompanied to the depletion in the intermediate energy levels by lowering the amount of defects in the structure of the composition.…”