Denitrification performance of non-pitch coal-based activated coke by the introduction of MnOx–CeOx–M (FeOx, CoOx) at low temperature

Abstract

Modified activated coke was prepared by the introduction of MnOx, CeOx, and M (FeOx, CoOx) into non-pitch coal-based activated coke (NPAC) using a novel non-pitch binder. The modified non-pitch coal-based activated coke was characterized in detail by N2 physical adsorption, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, temperature-programmed reduction of H2, temperature-programmed desorption of NH3, and its catalytic activity was examined by the selective catalytic reduction of NO with NH3 at low temperature. In addition, the SO2 and H2O tolerance was investigated. The results indicated that compared to MnOx–CeOx–4.39, Mn–Ce–Co/NPAC-7 and Mn–Ce–Fe/NPAC-7 exhibit considerably higher catalytic activities while simultaneously maintaining NOx removal rates of 78.98% and 77.85%, respectively, at 150°C. The high catalytic performance of Mn–Ce–Co/NPAC-a and Mn–Ce–Fe/NPAC-a is related to several better properties compared to MnOx–CeOx–4.39, namely, considerably higher specific surface areas and percentages of Oα/(Oα+Oβ+Oγ) and Ce3+/(Ce3++Ce4+), more easily reduced of Mn species, high reducibility, and more acidic sites. Furthermore, Mn–Ce–Co/NPAC-7 and Mn–Ce–Fe/NPAC-7 exhibited specific resistance to SO2 and H2O poisoning, and the SO2 deactivation mechanism was proposed.