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.