Ionic Liquid Assisted Hydrothermal Syntheses of Au doped TiO2 Nanoparticles for Efficient Visible-light Photocatalytic Hydrogen Production from Water, Electrochemical Detection and Photochemical Detoxification of Hexavalent Chromium (Cr+6) and Hydrothermally and ionic liquid assisted hydrothermally derived Y2O3/TiO2 nano-composites for efficient hydrogen production from water- a comparative study.