approximately 50 m2 g−1 Brunauer–Emmett–Teller (BET) surface area, 80% anatase–20% rutile mixture) were used as the nanocrystalline TiO2 particles. Specifically, 70 g of TTIP and 9 g of PEG were first mixed in 50 g of IPA and stirred at room temperature for 1 h