Solar light-driven photocatalyst based on bismuth molybdate (Bi 4 MoO 9 ) for detoxification of anionic azo dyes in wastewater

One of the most important challenges in photocatalysis research is to develop a new photocatalyst with an excellent solar light-harvesting capacity and a very high electron–hole separation efficiency. Herein, a bismuth molybdate (Bi 4 MoO 9 ) photocatalyst has been successfully prepared by a facile and capping agent-free chemical precipitation technique without using of any expensive reagent or surfactant. It is simple, catalyst-free, and easily fabricated. The prepared Bi 4 MoO 9 photocatalyst belongs to the face-centered cubic phase with an energy bandgap of 3.18 eV and spherical morphology of 64 nm. The photocatalyst provided the efficiency about 70% and 100% toward photodegradation of reactive red 141 (RR141) dye and Congo red (CR) dye, respectively. Interestingly, the photocatalyst showed an enhanced solar light-driven photoactivity of 100% toward degradation of Congo red (CR) dye in 30 min. The degradation reaction followed the first-order kinetics. Electron and hole played a vital role in dye degradation. The chemical structure of the photocatalyst remained stable after five cycles. The photocatalyst retains its original efficiency even after the fifth run implying the advantages of stability and reusability. The prepared Bi 4 MoO 9 will be suitable for degradation of toxic dyes in the environmental protection. The present finding offers a new avenue for fabrication of solar light-responsive photocatalyst for detoxification of organic pollutants.