Hydrogenation based disorder-engineered visible active N-doped mixed phase titania

• Synergy of hydrogenation and nitrogen doping influence the intrinsic property of titania.
• Tailing of conduction band minimum and localized energy states at valance band maximum make the catalyst visible active.
• Reduced recombination due to mixed phase present in the system.
• Swift carrier transport due to hydrogenation.

The anionic doping of a titania catalyst system results in extension of its effective absorption spectrum due to formation of localized impurity states above valence band edge. Also hydrogenation based disorder-engineering induces band tailing which provides a red-shift in absorption spectrum and creates more number of Ti3+ which has a stabilization effect on the nitrogen induced impurity states. Further, the mixed phase titania consistently shows improved activity as it reduces the recombination of charge carriers very effectively as well due to band-offset at phase junction. We synthesize a hydrogenation based disorder-engineered and nitrogen doped mixed phase titania (H–N–TiO2(M)) photocatalyst system with an aim to have a superior photocatalysts with all the attributes which have never been demonstrated earlier in a single system to have complementary effect on its performance. In this work commercial catalyst Degussa P25 (DP25) is used as a reference catalyst for the activity comparison. The characterization results show the existence of the intended attributes in the photocatalyst and kinetic study results reveal that the H–N–TiO2(M) system has 19 times higher activity compared to reference system under visible light.

Graphical representation of nitrogen doping and hydrogenation process in the tube furnace and photocatalysis mechanism of the catalyst under light illumination.Figure optionsDownload as PowerPoint slide