CuO@SiO2 was also synthesized by the SDL in a similar manner, as described in the experimental section. The synthesis used the products of CuO NPs synthesis described before, again after combining several batches. The resulting particles were analyzed by TEM (see Figure (e)) and show CuO cores with a thin mesoporous shell. The size distribution recorded from the images, represented in Figure gave a mean particle size of 91.9 ± 15.6 nm.