Zr-doped silver niobates for photocatalytic degradation of methylene blue and Rhodamine B dyes

Pristine silver niobate and Zr-doped silver niobates as photocatalysts were synthesized by the sol-gel method. The synthesized samples were characterized by X-ray diffraction (XRD) and were found to contain both AgNbO₃ and AgNb₃O₈. Fourier transform infrared (FT-IR) shows that the Nb-O bonds among the samples are different and may be attributed to the two types of silver niobates. Field emission scanning electron microscopy (FESEM) showed changes in morphologies of particles with increasing Zr-doping with average particle size ranging from 0.89 µm to 1.21 µm. The Tauc plots indicate that Zr-doped silver niobates have lower band-gap energies than their undoped counterpart. Furthermore, Zr-doped silver niobates also have a lower rate of electron-hole recombination than the undoped silver niobate as proven by the PL analysis. The photocatalytic degradation studies showed that Zr doping improved the performance of silver niobate for both Rhodamine B and methylene blue dyes. Through the present study, the link between Zr-doping and its role in dye degradation by silver niobates could be established.