Promotion of redox and stability features of doped Ce–W–Ti for NH₃-SCR reaction over a wide temperature range

Graphical abstract: In this study, different transition metals were introduced into Ce–W–Ti catalyst in order to promote the low temperature activity. The Cu/Ce–W–Ti catalyst prepared via a co-precipitation method displayed more excellent performance in the wide temperature range (260–400 °C). - Highlights: • Redox ability of Ce–W–Ti was enhanced by introduction of CuO. • The optimum catalyst provided high activity and broad operation window. • Cu/Ce–W–Ti presents an adequate tolerance to SO₂ and hydrothermal aging. - Abstract: In this study, transition metals Co, Mn, and Cu were introduced into a Ce–W–Ti catalyst to promote low-temperature catalytic activity. Among these metal-modified M/Ce–W–Ti catalysts (M represents Co, Mn, or Cu), the Cu/Ce–W–Ti catalyst with an optimized Cu content of 5 wt.% exhibited more than 90% conversion of nitrogen oxide (NO_x) in the selective catalytic reduction by NH₃ over a wide temperature range (260–400 °C). This catalyst likewise exhibited higher resistance to SO₂ gas and water vapor under severe test conditions. On the basis of the characterization results by powder X-ray diffraction and X-ray photoelectron spectroscopy, we concluded that the superior catalytic properties of the Cu/Ce–W–Ti catalyst could be attributed to the highly dispersed Cu species, which increased the contents of Ce³⁺ species and adsorbed oxygen species in the catalysts. In addition, the NH₃ temperature-programmed desorption results demonstrated that the Cu species doped into the Ce–W–Ti catalysts optimized surface acid content.