Promotional effect of Cu additive for the selective catalytic oxidation of n-butylamine over CeZrOx catalyst

Abstract

The catalytic elimination of nitrogen-containing volatile organic compounds (NVOCs) still encounters bottlenecks in NOx formation and low N2 selectivity. Here, a series of Cu-promoted Ce-Zr mixed oxide catalysts were synthesized using a simple precipitation approach, and n-butylamine was adopted as the probe pollutant to evaluate their catalytic performance. The CeCu10%ZrOx catalyst exhibited the best catalytic activity, with 100% n-butylamine conversion and 90% N2 selectivity at 250 °C. Concurrently, this sample also displayed good water resistance. A detailed characterization of the catalyst was performed through a series of experimental studies and theoretical calculations. The addition of Cu increased the redox property and promoted the production of oxygen vacancies, all of which were favorable for the greatest n-butylamine selective catalytic oxidation performance. The changes of oxygen vacancies over CeCu10%ZrOx in reaction process were studied by in situ Raman spectra. Moreover, in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) and theoretical calculations were employed to explore the reaction mechanism of n-butylamine selective oxidation. The high activity and selectivity of this catalyst confirm the practical feasibility of the selective oxidation of n-butylamine to CO2 and N2, and the exploration of the reaction mechanism provides new insights into the further design of catalysts.