Novel diatom-FeO_x composite as highly active catalyst in photodegradation of Rhodamine-6G

We report the study of nanoporous silica-iron oxide composite generated from diatom frustules as a highly active catalyst for the photodegradation of the dye Rhodamine-6G. The unique architecture and high surface area of diatoms were utilized to immobilize iron oxide on their surface to form the composite. Photodegradation was carried out under 365-nm radiation and was observed using the absorption spectrum of the dye. The reaction was found to follow pseudo-first-order kinetics. The results were compared with commercially available granular iron oxide. The rate constant K (min^-1) for photodegradation by the diatom composite was found to be as high as 0.0584 min^-1 for diatom-FeO_x composites, which is 52% higher than 0.0273 min^-1 for granular FeO_x at a dye concentration of 0.02 mm. The unique structural morphology and the synthetic strategy have led to the composites showing superior activity in the degradation of the dye Rhodamine-6G.