A fluorine free method to synthesize nitrogen and lanthanum co-doped TiO2 nanocrystals with exposed {0 0 1} facets for enhancing visible-light photocatalytic activity

• A fluorine free method used to synthesize N and La co-doped TiO2 nanosheets.
• The nanosheets exposed with dominated (0 0 1) facets.
• DEA plays an important role in the formation of (0 0 1) facets.
• N,La–TiO2 nanosheets shows higher visible light photocatalytic activity than N,La–TiO2 nanoparticles.
• N and La co-doping could produce a synergistic effect.

This study introduces a simple and fluorine free route to synthesize nitrogen and lanthanum co-doped TiO2 nanocrystals with exposed {0 0 1} facets through one-step hydrothermal method. The microstructure, chemical composition, and photocatalytic property of the co-doped TiO2 nanosheets were analyzed using XRD, FESEM, TEM, XPS and UV–vis. The experimental results indicated that N had been successfully doped into TiO2 lattice, while La was likely to form a binary nanocomposite with TiO2. The co-doped TiO2 nanosheets showed an additional visible light absorption band starting from 400 nm, which could improve the visible light photocatalytic activity of the sample. As the shape-controlling agent, DEA plays a crucial role in the formation of {0 0 1} facets. N and La co-doping could produce a synergistic effect. N doping can narrow the band gap of anatase TiO2 and increase the utilization efficiency of visible light, while La doping can enhance the separation efficiency of photo-induced electrons and holes. N and La co-doped TiO2 nanosheets exhibited higher visible light photocatalytic activity compared with P25, N doped TiO2 nanosheets and N, La co-doped TiO2 nanoparticles with the same doping concentration. In addition, N and La co-doped TiO2 nanosheets showed well recycling performance.

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