Detoxification of organic pollutants over novel niobium and cobalt codoped molybdenum oxy-sulfide photocatalyst under visible light.

Photocatalysis is one of the latest and the most promising technologies to remove organic pollutants from the environment. In this work, novel Nb/Co-codoped MoOS photocatalyst was prepared by a simple chemical precipitation method and thereafter the as-prepared photocatalysts were systematically characterized by different techniques. The photocatalytic performance of the as-prepared samples was surveyed by the degradation of methyl orange (MO), rhodamine B (RhB), and methylene blue (MB) dyes under visible light irradiation. All the codoped photocatalysts exhibited enhanced photocatalytic activity than pure and mono doped samples for degradation of these dyes with the highest degradation efficiency observed for the sample with 10 % Nb amount, which degrade 94.4 % of MO, 97.1 % of RhB, and 99.7 % of MB within 150, 20, and 40 min irradiation time, respectively. The HPLC test further confirmed the degradation of these dyes. The rate constants of MO, RhB, and MB removal in the photodegradation process over 10Nb-10Co-MoOS were determined. The enhanced photocatalytic activity of the sample was due to high charge separation and inhibition of recombination of photogenerated electron-hole pairs. The scavenger studies indicate that the primary active species in the photocatalytic process for MO and MB were superoxide radicals and for RhB were hydroxyl radicals, indicating 10Nb-10Co-MoOS had be widely used for different dye degradation. The catalyst revealed excellent recyclability and stability even after three runs. Finally, a reasonable reaction mechanism was proposed.