Highly dispersed iron vanadate catalyst supported on TiO2 for the selective catalytic reduction of NOx with NH3

Abstract

An iron vanadate (FeVO4) catalyst supported on TiO2 with high dispersion has been developed and applied in the selective catalytic reduction (SCR) of NOx with NH3, showing high activity, N2 selectivity, and H2O/SO2 durability in medium temperature range. The formation of Fe3+–O–V5+ linkages with low coordination number of vanadium atoms was evidenced by EXAFS, indicating the presence of abundant surface defects for reactant adsorption and activation. The XPS showed that the FeVO4 phase was surface-enriched with VOx species acting as true active sites, and thus, high NH3-SCR activity and H2O/SO2 durability could be preserved similar to that of V2O5/TiO2. Additionally, the presence of electronic inductive effect between Fe3+ and V5+ as confirmed by XANES and XPS could effectively decrease the unwanted NH3 unselective oxidation, thus resulting in high N2 selectivity at high temperatures. This FeVO4/TiO2 catalyst is a potential candidate for the deNOx process for stationary flue gas or diesel exhaust.