Visible‐light‐driven photocatalytic efficiency of Co‐ and Gd‐doped LaNiO ₃ and effect of doping on photochemical, electrochemical, and ferroelectric properties

Abstract

Gadolinium-and Cobalt-doped La 1−y Gd y Ni 1−x Co x O 3 perovskite nanoparticles were synthesized using facile micro-emulsion route to investigate the doping effect of Gadolinium and Cobalt on structural, morphological, dielectric, electrochemical, and photocatalytic activities of LaNiO 3 . The characterization of as-synthesized material was performed using X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), UV-visible, and Raman scattering techniques. Structural analysis of Gd-and Co-doped LaNiO 3 shows single-phase distorted rhombohedral structure with successful doping of Gd and Co and particles size was estimated in the range of 25-45 nm with heterogeneous morphology. The CV (cyclic voltammetry), EIS (electrochemical impedance spectroscopy), and current-voltage (I-V) analysis revealed that the Gd and Co doping enhanced the electrical properties of LaNiO 3 . CV and EIS of Gd-and Co-doped composition (x, y = 0.50) electrode shows higher specific capacitance (148 Fg −1 ) vs undoped LaNiO 3 (95 Fg −1 ). The (I-V) results revealed that conductivity was improved by Gd and Co doping, the conductivity values for composition (x, y = 0.50) were 3.01 × 10 4 S/m vs 2.08 × 10 −3 S/m for undoped LaNiO 3 . Frequency dependent dielectric properties of La 1−y Gd y Ni 1 −x Co x O 3 synthesized material show decreasing trend in dielectric constant, dielectric loss, tangent loss by increase in frequency and AC conductivity was increased by the doping of Gd and Co in LaNiO 3 . Resistivity measurements show a decrease in resistivity by Gd and Co doping. Ferroelectric loop of the Gd-and Co-doped material shows an increased ferroelectric nature than LaNiO 3 . Photoluminescence spectra show an excitation peaks in visible region, which decreases as the dopant content (x, y) was increased. The band gap energy (E g ) was estimated using Tauc's plot and it was observed that by increasing the dopant (x,y) contents, the band gap was decreased (3.25-2.53 eV). Photocatalytic activity of LaNiO 3 and La 1−y Gd y Ni 1−x Co x O 3 was tested for Rhodamine B (RhB) dye under solar light irradiation. Result shows that the doped material was significantly more photocatalytically active than

Effective Enhancement of the Ferroelectric Performance of Polar Co-Gallate MOF by Doping M2+ Ions (M = Mg, Mn, Ni) into Framework Nodes

“…For example, a series of La 1−y Gd y Ni 1−x Co x O 3 (x, y = 0.0, 0.10, 0.20, 0.30, 0.40, 0.50) prepared by the microemulsion method not only present increased photocatalytic activity and electrical properties but also exhibit higher ferroelectric performance than that of parent LaNiO 3 . 22 What is more, research on doping of metal ions into the framework nodes of MOFs to improve ferroelectric behaviors was reported by our group in 2021. A polar Ni-MOF with a three-dimensional structure shows enhanced ferroelectric properties through doping Mg 2+ ions into framework nodes, while both polarization and coercive field gradually increase with enhancing the concentration of Mg 2+ ions in the whole structure, that is to say, parent Ni 2+ ions are replaced by Mg 2+ ions.…”

“…Over the past decade, the validity of the metal ion doping strategy has been verified in some ferroelectric materials. For example, a series of La 1– y Gd y Ni 1– x Co x O 3 ( x , y = 0.0, 0.10, 0.20, 0.30, 0.40, 0.50) prepared by the microemulsion method not only present increased photocatalytic activity and electrical properties but also exhibit higher ferroelectric performance than that of parent LaNiO 3 . What is more, research on doping of metal ions into the framework nodes of MOFs to improve ferroelectric behaviors was reported by our group in 2021.…”