Ta-substituted SnNb2-xTaxO6 photocatalysts for hydrogen evolution under visible light irradiation

Abstract

Ta-substituted SnNb2-xTaxO6 was successfully prepared via a solid-state reaction to study the effect of Ta insertion in Nb sites on the crystal structure, photophysical properties, and photocatalytic activities for hydrogen evolution. Analyses of X-ray diffraction patterns and Raman spectra revealed that the substitution of Ta caused not only a more tightly packed atomic structure with greater crystal structural distortion, but also a shorter M-O bond length in MO6 octahedra. Additionally, we observed a gradual increase in the band gap, changing the photoabsorption property and conduction band electronic structure. The SnNb1.4Ta0.6O6 photocatalyst showed enhanced hydrogen evolution compared to pristine SnNb2O6. This result was mainly attributed to better transport ability of the photo-generated charge carriers.