A promising catalytic solution of NO reduction by CO using g-C3N4/TiO2: A DFT study

Abstract

The direct catalytic reduction of nitric oxide (NO) by carbon monoxide (CO) to form harmless N₂ and CO₂ is an ideal strategy to simultaneously remove both these hazardous gases. To investigate the feasibility of using graphitic carbon nitride/titanium dioxide (g-C₃N₄/TiO₂) to catalyze the NO reduction by CO, we systematically explore the effect of the interfacial coupling between g-C₃N₄ and TiO₂ on the photo-induced carrier separation, the light absorption, and the surface reaction for the NO reduction by using density functional theory. The g-C₃N₄/TiO₂ is predicted to have a better photocatalytic activity for NO reduction than g-C₃N₄, due to the enhanced light absorption intensity and the accelerated separation of the photo-excited electron-hole pairs. By comparing the reaction routes on g-C₃N₄/TiO₂ and g-C₃N₄, the results indicate that the introduction of TiO₂ can keep the surface reaction process intact with the NO dissociation (N₂O formation) being the rate-determining (crucial) step. Moreover, TiO₂ can facilitate the desorption of NO reduction products, avoiding the deactivation of g-C₃N₄. This work shows that the composition of TiO₂ into g-C₃N₄ provides a promising catalyst in NO reduction by CO.

Keywords: CO; Density functional theory; NO reduction; Reaction mechanism; g-C(3)N(4)/TiO(2).