Abstract
Interfacial charge transfer is crucial in the efficient conversion of solar energy into fuels and electricity. In this paper, heterojunction composites were fabricated, comprised of anatase TiO2 with different percentages of exposed {101} and {001} facets and nitrogen-doped quantum dots (NGQDs) to enhance the transfer efficiency of photo-excited charge carriers. The photocatalytic performances of all samples were evaluated for RhB degradation under visible light irradiation, and the hybrid containing TiO2 with 56% {001} facets demonstrated the best photocatalytic activity. The excellent photoactivity of TiO2/NGQDs was owed to the synergistic effects of the following factors: (i) The unique chemical features of NGQDs endowed NGQDs with high electronic conductivities and provided its direct contact with the TiO2 surface via forming Ti–O–C chemical bonds. (ii) The co-exposed {101} and {001} facets were beneficial for the separation and transfer of charge carriers in anatase TiO2. (iii) The donor-acceptor interaction between NGQDs and electron-rich {101} facets of TiO2 could remarkably enhance the photocurrent, thus hindering the charge carriers recombination rate. Extensive characterization of their physiochemical properties further showed the synergistic effect of facet-manipulated electron-hole separation in TiO2 and donor-acceptor interaction in graphene quantum dots (GQDs)/TiO2 on photocatalytic activity.
Highlights
Anatase TiO2 is generally considered a better photocatalyst than rutile, mainly due to its attributes of longer exciton diffusion length, higher electron mobility, and longer carrier life time [1,2].The photocatalytic activity of anatase has been revealed to depend closely on the crystal surface [3,4].Clear pictures have shown that reduction and oxidation reactions would preferentially occur on{101} and {001} facets, respectively
Due to intrinsic defects and the fast carrier recombination rate, electron trapping in anatase TiO2 are unavoidable, which hamper the overall photocatalytic activity [6,7]
T3-nitrogen-doped quantum dots (NGQDs) previously reported Bond cases [25,32,38]. These results indicated the composite formation of TiO2 /NGQDs of Ti 2pThe C–O–Ti bonds
Summary
Anatase TiO2 is generally considered a better photocatalyst than rutile, mainly due to its attributes of longer exciton diffusion length, higher electron mobility, and longer carrier life time [1,2].The photocatalytic activity of anatase has been revealed to depend closely on the crystal surface [3,4].Clear pictures have shown that reduction and oxidation reactions would preferentially occur on{101} and {001} facets, respectively. Anatase TiO2 is generally considered a better photocatalyst than rutile, mainly due to its attributes of longer exciton diffusion length, higher electron mobility, and longer carrier life time [1,2]. The photocatalytic activity of anatase has been revealed to depend closely on the crystal surface [3,4]. Clear pictures have shown that reduction and oxidation reactions would preferentially occur on. The substantial electrons in anatase TiO2 generated via photoexcitation play an important part in many energy-related applications. Due to intrinsic defects and the fast carrier recombination rate, electron trapping in anatase TiO2 are unavoidable, which hamper the overall photocatalytic activity [6,7]
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