Bio-engineered nano-scaled black TiO 2 its peculiar dark light activity

In the pursuit of uncovering novel multi-functional materials, nano-scaled black TiO 2 was successfully bio-engineered for the first time using a non-intensive energy green bio-inspired process via Hibiscus sabdarifa flower natural extract as an effective chelating agent. Besides its black color appearance, the bio-engineered nano-scaled black TiO 2 exhibited a significant dark conditions activity with an optical bandgap significantly low of the order of 2.1 eV far below the values of standard white anatase, white rutile & white brookite of 3.0 eV. This low optical bandgap value of 2.1 eV was attributed to likely surface oxygen deficiency as sustained by the electron spin resonance investigations. Such an elevated activity was found to be effective for the decomposition of methylene blue (MB) in contaminated water.