Enhanced Photocatalytic Response of N Doped Niobium Titanates Prepared by Ion Exchange Process (original) (raw)

Abstract

Herein we report the homogeneous and effective substitution of O by N in the layered titanates. The resultant materials HTiNbO 5-x N x (350°C, 30 min) unveiled extraordinary band-to-band excitation and increased absorption intensity (induced by oxygen vacancies). Upward shift of valence band maximum by N 2p states is confirmed by photoelectron spectroscopy and is concluded as the source of band-to-band visible light excitation. The electrons generated upon visible light excitation in the conduction band of HTiNbO 5-x N x (350°C, 30 min) had strong reduction ability, reducing O 2 into active O 2 •radicals during photocatalysis. These findings are the clear evidence for the substantial role of doped N in achieving band-to-band visible-light photon excitation in layered titanates. The new physical insights into substitutional N in layered titanates with hydrogen bond (weak bond energy) gained here may have important implications for developing other efficient visible light photocatalysts by nonmetal doping.

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