Thee3caPinhointoecdatalYtic ProPerties of 13i2,-.Ti2,07-1.s. (x = 0, 0.5) Yr cmethodP coprecipitationare, risvia ab initio.calculations and experiments. A applied for thesynthesis ofcnano.Polvde)r 1:EY'rc)chlures- The. PYrochlore phase formation starts at (BizT12,07 and SSO C (Bil sTizOs 2s). NanoPowders are found to be a metastable character of PYrochlore phases. The Presence of bismuth and oxYgen vacancies thermalenhances the stabilitY of the Bi1.5Ti2,06,25 Phase in comParison with the Bi2Ti207 phase. The estimated crystallite size is 30-40 nm with noticeable agglomerates of about 100-300 nm according to scanning electron microscopy (SEM) and with the fUrmation of particles (510-580nm)) inthe aqueous medium. The isoelectric points of the nanopwdrs e to be shifted to the strongly acidic region, resulting. in the formation of negativesurfaceparticle charges of 33 mV (Bi2T1207)and 27 mV (Bii.sTi2,0623). at PH 5.88 in distilled wale'''. The specific surface area is 11.5 m2/g (B ' Tz'e0) and 12.00 m ig (Bii sTi20625).The use of;thegeneralized gradient approximation (GGA) with the Perdew Burke E12rn 12 rh7of (PBE) functional allows achieving an excellent greement behveen theoretical and exPerimental structural Parameters. The screened Coulomb hybrid HSE03 functional is the mostappropriatea for describing the optoelectronic properties. Bismuth titanate PYrochlores are wide-gap semiconductors with strong abilities to be active PhotocatalYsts under visible irradiation. The oPtical Eg Values for direct/indirect transition according to the experiment, 3.19/2.94 eV (x = 0) and. 3.24/3.03 eV (x = 0.5), and the DFT/HSE03 calculations, 2.92/2.87 (x 0a)ndansdui3ta.4b2le/ (x = 0.5), are in the visible light, region and are close. Th.edge Positions confirm the ability of the Pyrochlore.s to ac.teacsalPcli.ulotaci.tecadtalleYwstse-ffTehcteivpehmotaoscsaetsal f itch. aecctihvgehacsbxejeerns ev.athluaBtieiclsTthir20u621,51.,bande the decomPosition of rhodaillill.e B under visible irradiation. BlzT12.07 shows the highest activity in characteristics.