In-situ formation of carbon-doped cerium-zirconium solid solution as a superacid catalyst for the removal of NOx

Defects engineering in nanomaterials can be used to precisely and effectively modulate catalysts’ reactivity. Here we report a highly efficient NH3-SCR catalyst constructed with in-situ formation of carbon-doped CeZrO2−x with dual defects, in which O atoms are substituted by C atoms to generate surface oxygen vacancies and subsurface oxygen substitutions. The carbon-doped CeZrO2−x exhibit superior activity and better SO2/H2O resistance compared with traditional bulk CeZrOx and V2O5-WO3/TiO2. The related characterization results reveal that the surface oxygen vacancy and subsurface oxygen substitution resulted in the formation of a large number of unsaturated coordination Ce and Zr species on catalyst’s surface, which contributed to the adsorption and activation of NH3, thus promoting the catalytic activity. Meanwhile, the abundant oxygen vacancy also stimulated the E-R reaction pathway over carbon-doped CeZrO2−x. In addition, it was proved that more zirconium sulfate and unstable ammonium sulfate species were exposed over carbon-doped CeZrO2−x, benifiting the better SO2-tolerance.