Carbon deposition enhanced selective catalytic reduction of nitric oxide by a new catalytic process as well as increasing reducibility of catalyst

Abstract

Carbon deposition usually hinders catalytic activity in one catalysis. In this work, carbon-deposition influence was investigated on selective catalytic reduction (SCR) of nitric oxide (NO) by a theoretical−experimental method. Density-functional-theory calculations showed that carbon deposition increased adsorption energy of NO on oxide. For example, adsorption energy on Fe2O3 increased from 1.70 to 5.27 eV. Carbon deposition increased activity by following processes: NO adsorption, NO dissociation, oxygen transmittance, CO-group formation, and N2/CO2 evolutions. Among these stages, CO-group formation was a key step. Based on these computational predictions, an experimental SCR was carried out for the verification. As a result, a carbon-deposited catalyst had a better SCR activity (20% higher) than the corresponding oxide catalyst. Characterizations showed that carbon deposition increased the amounts of medium/strong acidic sites as well as the reducibility of the catalytic center. The main result of this article helps to understand the interface behavior of carbon on a catalyst during SCR. Above results are also in favor of designing a more effective SCR reactor to ensure a more stable running.