The role of Pt valence state and La doping on titanium supported Pt-La/TiO2 catalyst for selective catalytic reduction with H2

Abstract

As a promising technology for the removal of NOx at low-temperature, selective catalytic reduction of NOx by hydrogen (H2-SCR) has received attention. Although the H2-SCR removed of NOx more low temperature than the conventional SCR technologies, however, it provides relatively low N2 selectivity. In this study, La were used as a promoter to facilitate NOx to N2 conversion by providing more available NOx species in the Pt based catalysts. The results revealed that the catalyst having high metallic Pt ratio exhibited outstanding NOx conversion. The superior NOx to N2 conversion of La doped over Pt/TiO2 was ascribed to the offering available NOx species. The mechanism of Pt based catalysts were proposed that (1) the formation of NH3 as a intermediate then (2) subsequent selective catalytic reduction or (3) oxidation of ammonia to N2 or N2O. Overall, the proposed La doped Pt/TiO2 catalyst offers significant catalytic performance for H2-SCR.