Cu induced reconstruction of microporous structure of tungstophosphoric acid decorated popcarbon and the synergistic effects on NH3-SCR performance

Abstract

With the common biomass niblet utilized as the green precursor and tungstophosphoric acid (TPA) as the promoter, a novel popcarbon/TPA/CuOx hybrid catalyst was initially synthesized via an economical and rapid route. A series of characterization including high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction by H2 (H2-TPR), Fourier transform infrared spectroscopy (FTIR) and Raman were carried out. The morphology characterization manifested the microporous structure with beehive-like macropores. The abundant oxygenic functional groups provided plenty of anchoring sites to the introduced ingredients (TPA polyanions and copper species) to achieve a fine disperse of active sites, which was beneficial to adsorption and activation of the reactants. The catalyst presented excellent de-NOx performance up to 95% in the whole temperature regime from 100 to 350 °C, as revealed by activity tests of selective catalytic reduction (SCR). The synergistic interactions among carbon atoms, TPA anions, and isolated copper species at different valence states greatly strengthen the electron transfer effects, which should be responsible for the low activation energy of 25 kJ mol−1 and enhanced SCR performance at low temperatures.