Defective Anatase TiO2-x Mesocrystal Growth In Situ on g-C3 N4 Nanosheets: Construction of 3D/2D Z-Scheme Heterostructures for Highly Efficient Visible-Light Photocatalysis.

Environmental remediation by employing visible-light-active semiconductor heterostructures provides effective solutions for handling emerging contaminants by a much greener and lower cost approach compared with other methods. This report demonstrates that the in situ growth of nanosized single-crystal-like defective anatase TiO2-x mesocrystals (DTMCs) on g-C3 N4 nanosheets (NSs) can produce a 3D/2D DTMC/g-C3 N4 NS heterostructure with the two components held together by chemical bonds to form tight interfaces. This nanostructured heterostructure displayed remarkably improved photocatalytic activity toward the removal of the model pollutants Methyl Orange (MO) and CrVI under visible-light irradiation in comparison with the pristine DTMC and g-C3 N4 NS components, which suggests that both the oxidation and reduction abilities of the DTMC/g-C3 N4 NSs were simultaneously enhanced after fabrication. On the basis of the results of a systematic characterization, a reasonable mechanism for the photocatalytic activity based on a direct Z-scheme heterojunction is proposed and further verified by the measurement of . OH. This novel Z-scheme heterojunction endows the heterostructure with improved photogenerated electron/hole pair separation and a strong redox ability for the efficient degradation of wastewater pollutants. This work will be useful for the design and fabrication of direct Z-scheme heterostructured photocatalysts with novel architectures for applications in energy conversion and environmental remediation.