Photodeposition time dependant growth, size and photoactivity of Ag and Cu deposited TiO2 nanocatalyst under solar irradiation

Ag and Cu metals due to their strong surface plasmons and visible light sensitivities have been incorporated with TiO2 for various solar applications. But the effect of mutual interaction between these two metals and role of photodeposition (PD) time has not been studied which may bring new interfaces, more photonic absorptions and photocatalytic activities. So, the present work focuses not only on the enhanced photoactivity of binary deposition of Ag and Cu metal onto TiO2 compared to their monometallic counterparts but on the importance of wt % and PD time as well. The higher activity possessed by the binary metal deposited TiO2 catalyst has been credited to greater interfacial contact region, optimized photodeposition time and enhanced absorptions in the visible region. Further, Ag-Cu@TiO2 photocatalyst was optimised by varying the wt% and PD time (15, 30, 60 and 90 min.) of deposited metals. It was observed that with increase in PD time, the DRS intensity (400-700 nm) also increased in the respective manner. It has been established that the co-catalyst size and growth of nanoparticles (evidenced by TEM, EDS and DLS analysis) play a major role which vary as a function of UV irradiation time during preparation of nanocatalyst. Consequently, Ag-Cu@TiO2 co-catalyst prepared at 30 min PD time has been shown to have maximum co-catalytic activity for the degradation of neutral red (k x 10(-3) = 0.061 min(-1)) and phenol red (k = 0.028 min(-1)) dyes under solar irradiation which has been attributed to the controlled growth and well dispersed Ag-Cu nanodeposits.