Investigation of γ-AlOOH and NiWO4-coated boehmite micro/nanostructure under UV/visible light photocatalysis

Abstract

A large-scale boehmite (γ-AlOOH) sphere and NiWO4-coated boehmite micro/nanostructured materials were synthesized via a facile two-step hydrothermal method with microwave irradiation using a solution phase route. The morphologies and structures of the prepared samples were characterized by scanning electron microscopy, high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy, and their optical and photocatalytic properties were also measured. The samples boehmite, AN1 and AN2 (different concentrations by NiWO4) were evaluated under UV/visible-light irradiation, and the AN1 sample showed intense (92.6%) degradation of methyl blue dye of the three samples. This enhancement was explained reasonably by HR-TEM evaluated surface-coated core–shell structured γ-AlOOH@NiWO4 shell width was about 10–15 nm and the core–shell size 120 nm. From the optical analysis, the core–shell heteronanostructure new energy level was attributed to the synergistic effect between NiWO4 and boehmite. In particular, a down-conversion luminescence process at the 450 nm excited energy optimization of redox for the efficient photogeneration of electron–hole pairs. Additionally, trapping measurement showed that O2·− and OH· species generated in the photocatalytic process played a key role in the degradation reaction. Based on these findings, this approach may offer a new strategy for the fabrication of surface-controlled spheres of core/shell structure-based photocatalysts with enhanced efficiency for environmental remediation applications.