Multi-level trapped electrons system in enhancing photocatalytic activity of TiO2 nanosheets for simultaneous reduction of Cr (VI) and RhB degradation

This is the first time we report that P-doped anatase titanium oxide (TiO2) nanosheets can be fabricated by red phosphorus (RP) and TiO2 nanosheets using simply hydrothermal method, accompanying variation in surface species viz. Ti4+, O-2, Ti3+, oxygen vacancies (V-o) and P5+. The defect and impurity levels induced by moderate doping could facilitate the formation of charge trap centers or avoid the formation of charge recombination centers, resulting in remarkably enhanced photocatalytic activity. Moreover, the enhanced optical absorbance and transfer performance of photo-generated carriers were studied using UV-Vis spectroscopy, photoelectric spectrometry and TR-PL. Importantly, the formation of Ti-O-P bands may accelerated transmission of electrons, giving rise to the effective separation of photo-generated carriers. To the best of our knowledge, the Cr (VI) reduction and RhB removal rate obtained by this hybrid show comparatively competitive among other reports so far. It is believed that this work provide a promising approach for building a novel pathway for electron transport and more photocatalytic reaction centers on photocatalysts.