Visible-light-driven photocatalytic efficiency of Co- and Gd-doped LaNiO3 and effect of doping on photochemical, electrochemical, and ferroelectric properties

Gadolinium- and Cobalt-doped La1-yGdyNi1-xCoxO3 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 LaNiO3. 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 LaNiO3 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 LaNiO3. CV and EIS of Gd- and Co-doped composition (x, y = 0.50) electrode shows higher specific capacitance (148 Fg(-1)) vs undoped LaNiO3 (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 x 10(4) S/m vs 2.08 x 10(-3) S/m for undoped LaNiO3. Frequency dependent dielectric properties of La1-yGdyNi1-xCoxO3 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 LaNiO3. 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 LaNiO3. 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 LaNiO3 and La1-yGdyNi1-xCoxO3 was tested for Rhodamine B (RhB) dye under solar light irradiation. Result shows that the doped material was significantly more photocatalytically active than LaNiO3.The doped material degraded about 88.6% as compared with 35.3% of undoped LaNiO3. The LaNiO3 with Gd- and Co-doped material shows an enhanced dielectric, electrochemical, ferroelectric, photocatalytic activities, and narrowing in energy band gap which might have promising application in electronic, energy storage devices and as active photocatalyst under visible light.

Automated summary

Gadolinium- and Cobalt-doped La1-yGdyNi1-xCoxO3 perovskite nanoparticles were synthesized and found to enhance the electrical properties, dielectric, electrochemical, ferroelectric, and photocatalytic activities of LaNiO3 compared to undoped LaNiO3. The doped material showed improved conductivity, decreased resistivity, increased ferroelectric nature, and higher photocatalytic activity under solar light irradiation, with a narrowing in energy band gap.