Built-in Electric Field Assisted Photocatalytic Dye Degradation and Photoelectrochemical Water Splitting of Ferroelectric Ce Doped BaTiO₃ Nanoassemblies

Abstract

In the field of environmental remediation and sustainability, the built-in electric field of ferroelectrics has been regarded as a promising strategy to enhance photocatalytic (PC) dye degradation and photoelectrochemical (PEC) water splitting. Here, we report on Ce-doped BaTiO3 (BT) nanoassemblies prepared by a hydrothermal route. X-ray diffraction reveals the phase transformation from tetragonal to cubic on the sintering temperature and Ce doping. From X-ray photoelectron spectroscopy (XPS), the oxygen vacancies are found to be maximum for 4 mol % of Ce concentration. The ferroelectric and piezoelectric measurements disclose a higher remnant polarization (1.76 μC cm–2) and d33 coefficient (15 pCN–1) at 4 mol % due to the built-in electric field. Thus, we observed a significantly improved PC dye degradation with the rate constant (k) of 0.0139 m–1 (methylene blue), 0.0147 m–1 (methyl violet) at 4 mol %, and 0.0117 m–1 (congo red) at 6 mol %. PEC water splitting showed that the photoanode fabricated at 4 mol % of Ce exhibits enriched photocurrent density (1.45 mA cm–2), impressive early onset of water oxidation (−0.504 V), and hydrogen gas evolution (22.50 μmol h–1 cm–2). Poling studies display a significant enhancement in both PC and PEC properties indicating the built-in electric field assisted activities of Ce-doped BT nanoassemblies. The underlying mechanisms behind the degradation efficiency and improved photocurrent density are established via the built-in electric field facilitating charge carrier detachment and transport as evidenced by the photoluminescence decay and XPS valence band spectra.