Abstract

To further boost the charge separation and photocatalytic activity of TiO2 under visible light, the anatase–rutile mixed-phase nitrogen-doped (N-doped) TiO2 nanoparticles were successfully synthesized through a facile one-step calcining procedure using TiN as raw materials. The crystal phases, morphologies, chemical compositions, textural structures, and optical properties of as-obtained N-doped TiO2 were characterized by the corresponding analytical techniques. The photocatalytic activities of as-fabricated samples were evaluated by degrading 4-chlorophenol (4-CP) and methylene blue (MB) aqueous solution under visible light irradiation. The results revealed that the ratio of rutile to anatase increased with the improvement of sintering temperature, and the sample prepared at 500 °C had the best photocatalytic activity. This might be because it possessed the most appropriate rutile/anatase proportion as well as the nitrogen doping. The transient photocurrent responses, photoluminescence spectra (PL) measurements, and active species trapping experiments were implemented to disclose the photocatalytic mechanism. This work will provide a further insight into the synthesis of highly efficient N-doped TiO2 photocatalysts for organic contaminant removal.

Highlights

  • Semiconductor photocatalysis technology has drawn great attentions in view of its promising application in converting solar energy into chemical fuels and decomposing harmful organic contaminants [1,2,3,4]

  • N-doped TiO2 photocatalysts with visible light response were fabricated by directly annealing TiN powder in a muffle furnace

  • The obtained N-doped TiO2 was constituted with anatase and rutile phase

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Summary

Introduction

Semiconductor photocatalysis technology has drawn great attentions in view of its promising application in converting solar energy into chemical fuels and decomposing harmful organic contaminants [1,2,3,4]. TiO2 -based photocatalysts with visible light response and slow recombination rate of photogenerated electron-hole pairs To realize this goal, surface modification by plasmonic metal nanoparticles (such as Au), constructing composites by coupling TiO2 with a narrow bandgap semiconductor, and doping. The anatase–rutile phase junction is supposed to increase charge separation efficiency and enhance photocatalytic activity. Some research groups have constructed the anatase–rutile phase junction photocatalysts by different synthetic approach, and they all present the enhanced photocatalytic performance in contrast with the single phase TiO2 [33,34,35,36,37,38]. On the basis of the above mentions, incorporating nitrogen doping with the formation of anatase–rutile phase junction would endow TiO2 with the excellent visible light photocatalytic activity. A possible mechanism for the enhanced photocatalytic activity was proposed based on the experimental results

Photocatalyst Characterization
FE-SEM
Photocatalytic Activity and Mechanism
Material Preparation
Material Characterization
Photocatalytic Activity Measurement
Photoelectrochemical Measurement
Active Species Trapping and Hydroxyl Radical Measurement
Conclusions
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