In
accordance with the cerium-lanthanum ratio of fluorocerium ores in the
mineralogy of the Baiyun Ebo process, the (Ce,La)CO3F grains were
synthesised by hydrothermal method using pure material to simulate bastnaesite
minerals, and used as NH3-SCR denitrification catalysts. The
activity results showed that the synthetic (Ce,La)CO3F was roasted
at 500˚C, and the NOx conversion was 27% at 200˚C. The NH3-SCR catalytic activity of the synthesised (Ce,La)CO3F was
improved by loaded transition metal Mn. The best catalyst was found to be
produced by impregnating (Ce,La)CO3F with 1 mol/L manganese nitrate
solution, with a NOx conversion of 80% at 250˚C. The loading of Mn resulted in the appearance of numerous well-dispersed
MnOx species on the catalyst surface, the dispersion of Ce7O12 species was also greatly enhanced, and the reduction in grain size indicated
that Mnn+ entered into the (Ce,La)CO3F lattice causing
lattice shrinkage. The number of acidic sites on the catalyst surface and the
redox capacity were enhanced. The amount of Ce3+ in the catalyst was
also enhanced by the introduction of Mnn+, but the proportion of
adsorbed oxygen decreased, which indicated that the introduction of Mnn+ was detrimental to the increase in the proportion of adsorbed oxygen. The
reaction mechanisms of the (Ce,La)CO3F and Mn/(Ce,La)CO3F
catalysts were investigated by in-situ Fourier transform infrared spectroscopy (FTIR). The results showed that
catalysts followed the E-R and L-H mechanisms. When loaded with Mn, the main
reactive species in the L-H mechanism were the
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