The photocatalytic performance of Fe inserted in Nb2O5 obtained by microwave-assisted hydrothermal synthesis: Factorial design of experiments

Nb2O5 and Fe inserted Nb2O5 from 1 to 3 % were synthesized by the microwave-assisted hydrothermal method. The XRD results confirm the presence of Nb2O5 with low crystallinity in all samples, which is characteristic of the material that was not subjected to heat treatment. The SEM images show that the insertion of Nb2O5 with Fe promotes the formation of pores on the surface of the material. The addition of Fe also led to a decrease in the band gap to pure Nb2O5. The photocatalytic performance for the degradation of rhodamine B was evaluated. The 1 %Fe-Nb2O5 sample showed the best photocatalytic discoloration result, achieving 100 % discoloration of RhB within 60 min. The increase in ion concentration leads to a decrease in photocatalytic performance. A 24 factorial design experiment was performed for samples of Nb2O5 and Nb2O5 with 1 %Fe-Nb2O5. The study variables were catalyst type (Nb2O5 and 1 %Fe-Nb2O5), catalyst dosage (25 and 50 mg), pH of the RhB solution (5 and 10), and time of photocatalytic analysis (30 and 60 min) to check the effect on the RhB discoloration. The analysis showed that the change in catalyst, catalyst dosage, pH and reaction time had a significant effect. Most of the interactions between the variables also had a significant effect on the process, both positively and negatively. The diversi-fication of the results of the factorial design, variables, and their interactions allowed us to identify the best execution routes of heterogeneous photocatalysis for the removal of RhB, depending on the parameters used in this work.

Automated summary

In this study, Nb2O5 inserted with Fe was synthesized using the microwave-assisted hydrothermal method. The insertion of Fe promoted the formation of pores and decreased the band gap of Nb2O5. The 1%Fe-Nb2O5 sample showed the best photocatalytic discoloration result. The increase in ion concentration led to a decrease in photocatalytic performance. The factorial design experiment revealed the significant effects of catalyst type, catalyst dosage, pH, and reaction time on the degradation of RhB.