Nitrogen doping of TiO2 photocatalyst forms a second eg state in the Oxygen (1s) NEXAFS pre-edge

TL;DR

This study identifies a new eg resonance in oxygen NEXAFS spectra of titanium oxynitride photocatalysts, linking it to enhanced photocatalytic activity under visible light.

Contribution

It reveals a previously unnoticed eg state in oxygen NEXAFS spectra of TiO2-based photocatalysts, correlating this state with improved photocatalytic performance.

Findings

Discovery of an additional eg resonance in oxygen NEXAFS spectra.

Correlation between the eg resonance intensity and photocatalytic efficiency.

Implication of the eg state in visible-light photocatalysis.

Abstract

Close inspection of the pre-edge in oxygen near-edge x-ray absorption fine structure spectra of single step, gas phase synthesized titanium oxynitride photocatalysts with 20 nm particle size reveals an additional eg resonance in the VB that went unnoticed in previous TiO2 anion doping studies. The relative spectral weight of this Ti(3d)-O(2p) hybridized state with respect to and located between the readily established t2g and eg resonances scales qualitatively with the photocatalytic decomposition power, suggesting that this extra resonance bears co-responsibility for the photocatalytic performance of titanium oxynitrides at visible light wavelengths.