Interstitial N-Doped TiO2 for Photocatalytic Methylene Blue Degradation under Visible Light Irradiation

Photocatalysis is a promising method for methylene blue (MB) degradation due to its effectiveness and environmental compatibility. Among the photocatalysts, titanium dioxide (TiO2) has been widely used for MB degradation due to its exceptional photocatalytic activity. However, the wide bandgap limits the degradation efficiency of TiO2under visible light. Here, an interstitial nitrogen-doped TiO2(5%NT/TiO2) used thiourea as the N source was fabricated for visible light-derived MB degradation. The 5%NT/TiO2exhibited an extended absorption range of visible light. Moreover, photoelectrochemical measurements showed an improvement in the photocurrent response and charge transfer behavior on N/TiO2. Thus, 5%NT/TiO2had enhanced photocatalytic activity compared with pristine TiO2and substitutive N-doped TiO2(5%NAB/TiO2). The accelerated photocatalytic MB degradation process on N/TiO2could be mainly attributed to the interstitial N doping, which caused the appearance of new energy states and extended optical properties. Through comparing the impact of interstitial and substitutive in TiO2activity, our work proposes a suitable form of element doping to enhance the optical properties and photocatalytic activity of TiO2and even other semiconductors, providing guidance for future work.