Fig. 2

A HR-TEM images of Cu-doped TiO₂ nanoparticles with lattice distance in the range of 0.18 to 0.21 nm. A1 and A2 show the HR-TEM and the area indicated with a white rectangle is shown as a zoomed in image in A1a and A1b, respectively. B TPR diagrams of pure B1) TiO₂, B2) 5%, B3) 10%, B4) 33% Cu doped TiO₂, B5) CuO and B6) Cu₂O Pure CuO shows two reduction signals around 240 °C and 310 °C which were attributed to reduction of Cu²⁺/Cu⁺ and Cu.⁺/Cu0, respectively. Each Cu doped TiO₂ display one peak indicating the presence of Cu₂O on the surface. C electron energy loss spectrocopy (EELS spectra) of (a) pure Cu measured using copper metal as an instrument standard (b) 10% Cu doped TiO₂ and (c) 33% Cu doped TiO₂. In all the three samples, the signals occur very similarly as metallic Cu. Hence, the small particles homogenously distributed on the TiO₂ matrix is concluded as metallic copper. D Representative heat map displaying the effect of the different NPs on the viability, cell area, cell aspect ratio and mitochondrial health of human lung adenocarcinoma (A549), human bronchoepithelial cells (Beas2B), human cervical tumor cells (HeLa) and murine lung adenocarcinoma (KLN 205)