TiO 2 nanofiber (200 mg) and CQDs (50 mg) were mixed into
20 ml of distilled water and 10 ml of alcohol. The mixture was
kept stirring for 30 min at room temperature to make a clear
dispersion of CQDs. After that, the dispersed solution was
transferred into a 40 ml Teflon-sealed autoclave and maintained
at 140 1C for 4 h. Finally, the resulting solution was cooled filtered, washed with distilled water three times and dried under
vacuum at 40 1C overnight.