Interestingly, the XRD spectra do not exhibit peaks corresponding to silver, even though it is a component of the tri-doped photocatalysts. This can be explained by the relatively low concentration of silver used in the synthesis process and the significantly larger ionic radius of silver compared to titanium and cerium. The small quantity and dispersion of silver within the TiO₂ matrix likely result in its XRD signal being below the detection limit. However, silver's contribution to the photocatalytic activity should not be underestimated, as it can enhance the catalyst's performance through surface plasmon resonance (SPR) effects and improved electron trapping.