Synthesis, characterization and enhanced visible-light photocatalytic activity of novel NiO/HTi2NbO7 nanocomposite

Abstract

The novel NiO/HTi₂NbO₇ nanocomposite was successfully synthesized by assembling HTi₂NbO₇ nanosheets with a nickel hydroxide precursor. The as-prepared NiO/HTi₂NbO₇ nanocomposite and its precursors were characterized by means of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) with energy dispersive spectrometer (EDS), N₂ adsorption–desorption measurements, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (UV-vis DRS), laser Raman spectroscopy (LRS), ¹H magic angle spinning nuclear magnetic resonance (¹H MAS NMR) spectra, current–time (i–t) curves and Mott–Schottky (M–S) curves. The catalytic activities of the as-prepared materials were evaluated by the photodegradation of methylene blue (MB) dyes. The results showed that NiO nanoparticles were distributed on the surface of HTi₂NbO₇ nanosheets successfully. The significant interaction between the dispersed NiO species and the hydroxyl groups on the nanosheets was observed via the ¹H-MAS NMR study of the nanocomposite, which was rarely explored before. The nanocomposite displayed an enhanced visible-light photocatalytic activity compared to that of the NiO nanoparticles and HTi₂NbO₇ nanosheet aggregation, which could result from the improved visible-light region absorption intensity and the decreased electron–hole recombination rate. It is suggested that this improvement comes from the synergistic effect between the host HTi₂NbO₇ and guest NiO in the nanocomposite.