| Summary: | Sb-containing catalysts (SbZrO<i><sub>x</sub></i> (SbZr), SbCeO<i><sub>x</sub></i> (SbCe), SbCeZrO<i><sub>x</sub></i> (SbCeZr)) were prepared by citric acid method and investigated for the selective catalytic reduction (SCR) of NO<i><sub>x</sub></i> with NH<sub>3</sub> (NH<sub>3</sub>-SCR). SbCeZr outperformed SbZr and SbCe and exhibited the highest activity with 80% NO conversion in the temperature window of 202–422 °C. Meanwhile, it also had good thermal stability and resistance against H<sub>2</sub>O and SO<sub>2</sub>. Various characterization methods, such as XRD, XPS, H<sub>2</sub>-TPR, NH<sub>3</sub>-TPD, and in situ diffuse reflectance infrared Fourier transform (DRIFT), were applied to understand their different behavior in NO<i><sub>x</sub></i> removal. The presence of Sb in the metal oxides led to the difference in acid distribution and redox property, which closely related with the NH<sub>3</sub> adsorption and NO oxidation. Brønsted acid and Lewis acid were evenly distributed on SbCe, while Brønsted acid dominated on SbCeZr. Compared with Brønsted acid, Lewis acid was slightly active in NH<sub>3</sub>-SCR. The competition between NH<sub>3</sub> adsorption and NO oxidation was dependent on SbO<i><sub>x</sub></i> and metal oxides, which were found on SbCe while not on SbCeZr.
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