Au-decorated Na_xH_(2-x)Ti3O7 nanobelts exhibiting remarkable photocatalytic properties under visible-light illumination

摘要

We demonstrated for the first time that Na-intercalated H2Ti3O7 (Na_xH_(2-x)Ti3O7) NBs, prepared in the typical alkaline hydrothermal process, can effectively absorb visible light to carry out photocatalytic reactions. With the capability of effective light absorption in visible range, Na_xH_(2-x)Ti3O7 NBs performed much better in the photodegradation of thionine than the other three counterpart products including H2Ti3O7, mixed Na2Ti6O_(13)/TiO2 and anatase TiO2 under visible-light irradiations. As compared to the relevant commercial products like β-25 TiO2 and Na2Ti3O7 powders, the as-synthesized Na_xH_(2-x)Ti3O7 NBs exhibited superior photocatalytic efficiency under UV illumination, demonstrating their potential as an efficient photocatalyst in relevant redox reactions. A further enhancement in the photocatalytic activity can be achieved for Na_xH_(2-x)Ti3O7 NBs when Au nanoparticles of suitable amount were deposited on their surfaces. This improvement is due to the band offsets between Na_xH_(2-x)Ti3O7 and Au, which may promote charge carrier separation to favor the photocatalysis. The recycling test reveals that Au-decorated Na_xH_(2-x)Ti3O7 NBs could be promisingly utilized in the long-term course of photocatalysis. Furthermore, the result of performance evaluation under natural sunlight shows that the current Au-decorated Na_xH_(2-x)Ti3O7 NBs can be used as highly efficient photocatalysts which may practically harvest energy from sunlight.