Sequential ionic layer adsorption reaction formation of LaVO4–TiO2 nanocomposites for photocatalytic water treatment

Abstract

Lanthanum vanadate (LaVO4) has been successfully deposited as a thin conformal layer onto the surface of P25 TiO2 particles immobilized on the surface of macroscopic glass beads. Using a simple sequential ionic layer adsorption reaction (SILAR) method, the LaVO4 layer is deposited in situ with good control over the loading. Both the prepared composites and individual LaVO4 and TiO2 materials have been thoroughly characterized by X-ray diffraction, electron microscopies, X-ray photoelectron spectroscopy. The coated bead samples have been applied in the photocatalytic degradation of the model organic pollutant 4-chlorophenol, with the optimal LaVO4 loading displaying ∼3× higher degradation of the pollutant than the pristine P25 sample. Using electrochemical and spectroscopic methods, band energies for both materials and the composite have been determined, and a provisional mechanism for degradation proposed upon the basis of this band alignment and upon scavenging experiments.