Structure and effective visible-light-driven photocatalytic activity of α-NiMoO4 for degradation of methylene blue dye

•A novel photocatalyst α-Ni(MoO4) powders was developed by Pechini method.•α-Ni(MoO4) shows high absorption in UV–vis. wavelength region.•α-Ni(MoO4) presents high activity in the MB degradation under visible light.•The structure has specialties: hexagonal tunnel connected by MoO4 and NiO6.

α-NiMoO4 powders were prepared by the Pechini method. The sample was investigated by X-ray powder diffraction (XRD) measurement, structural refinement, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). The average size of α-NiMoO4 powders was measured to be 250 nm. The optical absorption spectrum of α-NiMoO4 confirmed an efficient absorption in the UV–visible light wavelength region. The sample presents a narrowed band-gap energy of 2.23 eV, and the effective photocatalytic activity was evaluated by the photodegradation of methylene blue (MB). The effective photocatalytic activity was discussed on the base of the crystal structure characteristics such as heavily distorted NiO6, activated optical centers and good electric conductivity. These results indicate that the hexagonal tunnel-structure alternately connected by MoO4 and the heavily distorted NiO6 is the dominated superiority for high photocatalytic capacity.

Graphical abstractα-Ni(MoO4) powders show high absorption in UV–vis. wavelength region and high activity in the MB degradation under visible light. This is due to its structural characteristics such as the hexagonal tunnel structure alternately connected by MoO4 and heavily distorted NiO6 octahedra.Figure optionsDownload full-size imageDownload as PowerPoint slide