NH3-SCR performance improvement of mesoporous Sn modified Cr-MnOx catalysts at low temperatures

• We synthesized the highly ordered mesoporous Sn/Cr-MnOx by the “nanocasting” method.
• The mesoporous materials exhibit a high low temperature SCR catalytic performance.
• The addition of Sn improved the sulfur resistance.

A series of mesoporous Sn/Cr-MnOx nanomarerials with highly ordered three-dimensional channels were successfully prepared by the “nanocasting” method, which were used as selective catalytic reduction (SCR) catalysts to remove NOx with NH3 in a low-temperature range (150–300 °C). All of the mesoporous catalysts exhibited highly ordered mesoporous structure and high surface areas, and the SnOx nanoparticles were well dispersed in the mesoporous channels. Among all the Sn/Cr-MnOx samples, the 0.16-Sn/Cr (0.1)-MnO2 sample showed the best activity, giving the near 100% NOx conversion at 150–250 °C. From the XPS results, it can be found that doped Sn element significantly increased the proportion of Cr3+/Cr2+ and Mn3+/Mn4+ that may improve the N2 selectivity. Moreover, higher content of adsorbed oxygen and improved surface reducibility were also observed. In addition, Sn modified catalysts showed excellent SO2 resistance.

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