Effect of Bi³⁺ Ion Concentration on Physicochemical, Optical and Catalytic Properties of One‐Pot Combustion Synthesized Nanocrystalline Bi‐Doped La₂O₃

Abstract

La 2-2x Bi 2x O 3 (x = 0-0.04) nanocrystalline powders are synthesized by one-pot single step solution combustion method. 4 atom% Bi doped La 2 O 3 reveals the presence of both Bi 3 + and metallic Bi. Temperature programmed reduction (TPR) of La 2 O 3 and La 2 À 2x Bi 2x O 3 (x = 0.005-0.04) indicates that the oxygen storage capacity changes with the dopant (Bi) concentration. La 2-2x Bi 2x O 3 (x = 0.04) has less hygroscopic behavior compared to La 2 O 3 and shown enhanced stability in an open atmosphere. The direct band gap of La 2 O 3 and La(OH) 3 decreases significantly after Bi doping. Further, PL studies of Bi doped compounds show a blue emission at 458 nm due to 3 P 1-1 S 0 transition of the Bi 3 + ion substituted in La 2 O 3. Emission intensity is maximum with 0.5 atom percent Bi doping, which decreases gradually with increasing Bi 3 + ion concentration. Bi doping also modifies the catalytic activity of La 2 O 3, resulting in higher CO oxidation activity than unsubstituted La 2 O 3 .

Tunable luminescence from Bi3+ sensitized La2Zr2O7:Eu3+ red nanophosphors for display applications

“…The emission spectra of Bi 3+ doped samples at 465 nm (blue) revealed a broad peak maximum, which is ascribed to the electronic transition 3 P 1 → 1 S 0 of Bi 3+ , when excited at 310 nm. [ 46,47 ] Figure 5d depicts the lifetime decay curves of Bi 3+ doped samples. The emission intensity at 460 nm increases initially as the Bi 3+ concentrations increase and reaches a maximum for 0.5 at% Bi 3+ , then declines for higher concentrations; this is caused by the concentration quenching effect.…”