Sputter -coated N-enriched mixed metal oxides (Ta2O5-Nb2O5-N) composite: A resilient solar driven photocatalyst for water purification.

ABSTRACT

This study demonstrated the formation of N-enriched mixed metal oxides (Ta2O5-Nb2O5-N and Ta2O5-Nb2O5) thin film composites used as photocatalysts to degrade P-Rosaniline Hydrochloride (PRH-Dye) dye under solar radiation. By controlling the N gas flow rate during the sputtering process, the N concentration in the Ta2O5-Nb2O5-N composite is significantly included, and demonstrated by XPS and HRTEM analysis. With the help of XPS and HRTEM investigations, it was determined that the addition of N to Ta2O5-Nb2O5-N significantly enhances the active sites. The Ta-O-N bond (N 1 s and Ta 4p3/2 spectra) was verified by the XPS spectra. Ta2O5-Nb2O5 was found to have a lattice interplanar distance (d-spacing) of 2.52, whereas Ta2O5-Nb2O5-N showed the 2.5 (620 planes). A sputter-coated Ta2O5-Nb2O5and Ta2O5-Nb2O5-N photocatalysts were prepared, and their photocatalytic activity was evaluated using PRH-Dye as a model pollutant under solar radiation by adding H2O2 (0.01 mol). The photocatalytic activity of the Ta2O5-Nb2O5-N composite was compared with TiO2 (P-25) and Ta2O5-Nb2O5. Ta2O5-Nb2O5-N showed very high photocatalytic activity compared to Degussa P-25 TiO2 and Ta2O5-Nb2O5 under solar radiation and confirmed the presence of N in Ta2O5-Nb2O5-N significantly increased the generation of ˙OH radicals (in pH 3, 7 and 9). With the use of LC/MS, the stable intermediates or metabolite created during the photooxidation of PRH-Dye were assessed. The results of this study will provide useful insights on how Ta2O5-Nb2O5-N influences the efficiency of water pollution remediation.