Photocatalytic activity of Nb heterostructure (NaNbO3/Na2Nb4O11) and Nb/clay materials in the degradation of organic compounds.

Abstract

In this article, Nb heterostructure-based (NaNbO3/Na2Nb4O11) and Nb/Clay-based materials were prepared, characterized and evaluated for the Rhodamine B (C28H31ClN2O3) photodegradation under UV radiation (253.7 nm). As far as this research understands, this is the first time that the photocatalytic activity of the Nb heterostructure (NaNbO3/Na2Nb4O11) is reported. Nb heterostructure is composed of sodium niobate and dis- odium tetraniobium hendecaoxide (NaNbO3/Na2Nb4O11). The material was synthesized by a simple and eco- nomic method via basic precipitation of ammoniacal niobium oxalate (NH4 [NbO (C2O4)2·H2O] XH2O) followed by thermal treatment at 500 °C. Nb/Clay-based materials were synthesized from the natural clay suspension (Montmorillonite) precursor. The addition of Nb to the natural clay by the methodology employed in this work modified the band-gap energy and increased the specific surface area of the resultant materials (to almost twice the value of the original specific surface area). Furthermore, this addition also decreased the luminescence and trap centres and potentiated the photocatalytic activity of the Nb/Clay materials. The Nb heterostructure showed higher photocatalytic activity in Rhodamine B photodegradation (recorded up to 95% removal at natural con- ditions). Similar values were reported to Nb/Clay materials. Despite the natural clay having more luminescence and trap centres than Nb/Clay materials, it recorded very low photocatalytic activity. Nb addition to natural clay increased the photocatalytic activity of the material, which would give other use to clay along with being used as an adsorbent.