Carbon quantum dots/TiO2 nanosheets with dominant (001) facets for enhanced photocatalytic hydrogen evolution.

Abstract Carbon quantum dots/TiO 2 nanosheets with a majority of (001) facet (CQDs/TiO 2 -001) samples are successfully prepared via a facile method. Compared to TiO 2 -001 and CQDs/P25, the synthesized CQDs/TiO 2 -001 presents a remarkably higher photocatalytic activity for H 2 evolution with a considerable stability. XRD, XPS, HRTEM, FESEM, FTIR, Photoluminescence (PL) spectroscopy, Fluorescence spectroscopy and UV–visible reflectance spectroscopy are adopted to investigate the morphology, structure and properties of synthesized CQDs/TiO 2 -001. The mechanism of the improved photocatalytic activity over CQDs/TiO 2 -001 is also investigated. The results show that the improved photocatalytic activity over CQDs/TiO 2 -001 can be attributed to the synergistic effects of TiO 2 -001 and CQDs: the highly exposed (001) facets of TiO 2 -001 promote the transportation of photogenerated electrons and the loading of CQDs restrains the recombination of electrons-holes on (001) facets. Meanwhile, the visible-light absorption is extended because the CQDs serve as a photosensitizer and sensitize TiO 2 -001 through the newly formed Ti O C bond between the CQDs and TiO 2 -001. Graphical abstract Unlabelled Image Highlights • CQDs/TiO 2 with dominated (001) facet are prepared via a facile method. • CQDs/TiO 2 -001 exhibits excellent photocatalytic activity for H 2 evolution. • Synergistic effect of CQDs and (001) facet leads to superior performance. [ABSTRACT FROM AUTHOR]