Visible light-response NaTa1−xCuxO3 photocatalysts for hydrogen production from methanol aqueous solution

Abstract

Visible light-response NaTa1−xCuxO3 photocatalysts were prepared using a traditional solid-state reaction process, and well characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometer (EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and UV–Vis diffuse reflectance spectra (UV–Vis DRS). The photocatalytic activities were evaluated via photocatalytic hydrogen production in the methanol aqueous solution under visible light irradiation (λ>400nm). The doping of Cu(II) into NaTaO3 lattice makes the characteristic step more obvious on the surface and leads to significant red shift of optical response towards visible light. The sample doped with 8% Cu(II) and loaded with 0.3wt% NiO co-catalyst exhibited a dramatic increase of the activity without deactivation for 36h in the hydrogen production reaction. The optimal loading of the co-catalyst is related to the surface textural properties of the composites. The enhanced visible light photocatalytic activity is mainly due to the donor level provided by the doped Cu(II) contributing to the valence band of the composite and the ordered nano-lamellar structure leading to more active sites for hydrogen production.