Surface modification of Na-K₂Ti₆O₁₃ photocatalyst with Cu(II)-nanocluster for efficient visible-light-driven photocatalytic activity

A novel visible light sensitive Cu(II)-nanocluster grafted Na-K₂Ti₆O₁₃ photocatalyst was prepared via molten salt method followed by impregnation technique. The prepared samples were characterized with various analytical techniques to validate the grafting of nanocluster onto the surface of Na-K₂Ti₆O₁₃. TEM analysis shows belt-like morphology with diameter of 10–20 nm. In addition, a cluster of size less than 5 nm was observed on the surface of the catalyst belt, indicating the grafting of Cu(II) rather than its doping onto the catalyst lattice. The surface modified Na-K₂Ti₆O₁₃ nano-belt showed propitious photocatalytic activity over pure Na-K₂Ti₆O₁₃ for the degradation of Rhodamine B. Among the series of different wt% Cu-grafting, 0.1% Cu-grafted Na-K₂Ti₆O₁₃ showed highest photocatalytic activity for the degradation of dye with 87% degradation within 80 min of illumination. The enhanced photocatalytic activity could be attributed to direct interfacial charge transfer (IFCT) from VB of Na-K₂Ti₆O₁₃ to the surface grafted Cu(II) nanocluster.