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 degrees C). All of the mesoporous catalysts exhibited highly ordered mesoporous structure and high surface areas, and the SnOx nanopartides 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 degrees 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 N-2 selectivity. Moreover, higher content of adsorbed oxygen and improved surface reducibility were also observed. In addition, Sn modified catalysts showed excellent SO2 resistance. (C) 2015 Elsevier B.V. All rights reserved.