1. Centre for Nanotechnology Research, VIT University, Vellore 632014, India
2. Photocatalyst and Coatings Group, SPECIFIC, College of Engineering, Swansea University (Bay Campus), Fabian Way, Swansea SA1 8EN,U.K.
3. Ira A. Fulton Schools of Engineering, Arizona State University, Mesa, Arizona 85212, United States
4. Climate Change Technology Research Division, Korea Institute of Energy Research, Yuseong-gu, Daejeon 305-343, South Korea