Preparation, characterization and electronic properties of LaFeO3 perovskite as photocatalyst for hydrogen production. (5th May 2023)

• Record Type: Journal Article
• Authors: Boulahouache, A.; Benlembarek, M.; Salhi, N.; Djaballah, A.M.; Rabia, Cherifa; Trari, M.
• Is Part Of: International journal of hydrogen energy. Volume 48:Number 39(2023)
• Page Start: 14650
• Page End: 14658
• Publication Date: 2023-05-05
• Subjects: Perovskite LaFeO3 -- Sol-gel -- Photoreduction -- Hydrogen -- Visible light; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.12.327
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Perovskite-type LaFeO3 was successfully used as photocatalyst for the H2 production. It was prepared by a conventional sol-gel technique via the nitrate route. X-Ray fluorescence/Energy Dispersive X-Ray fluorescence (XRF), X-Ray Diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), UV–Visible diffuse reflectance, FTIR spectroscopy, Scanning Electron Microscopy (SEM/EDX) and specific surface area were deployed to characterize the synthetized material after heat-treated at 850 °C. LaFeO3 crystallizes in a cubic structure (Space Group: Pm3 m) with a crystallite size of 16 nm and BET surface area of 12 m 2 /g. Field-dependent magnetization was measured at 300 K in the region (±25 kOe) and the perovskite exhibits a high magnetism with a saturation magnetization (0.15 emu/g). Such result indicates that the Fe- 3d are in localized high spin state. LaFeO3 has a narrow band gap of 2.08 eV determined by diffuse reflectance resulting to the crystal field splitting of 3 d orbital of Fe 3+ octahedrally coordinated with an internal d-d transition. Cyclic voltammetry showed the reduction of adsorbed H2 O molecules to gaseous hydrogen at −0.7 V SCE, a potential less cathodic than the conduction band (−0.45 VSCE ). The latter was determined from the capacitance measurements in alkaline electrolyte (NaOH 0.1 M) where the perovskite exhibits a stability with an exchange current density of ∼0.4 mA cm −2 . The photocatalytic activity reveals an optimal H2 production of 99 μmol after 20 min at 50 °C in NaOH medium and a catalyst mass of 50 mg, under visible light irradiation (13 W) in the presence of thiosulfate S2 O3 2− as hole scavenger. Highlights: Particles of 18 nm size close to the nanometric domain with the sol-gel method for the ferrite perovskite LaFeO3 . LaFeO3 active photocatalyst in visible light with a narrow band gap of 2 eV. H2 production increases in NaOH electrolyte in the presence of S2 O3 2− as hole scavenger.