Surface property and activity of Pt/Nb2O5-ZrO2 for selective catalytic reduction of NO by H2

Abstract

Series of 0.5 wt.%Pt/NbnZrm catalysts (n: m = 0 ˜ 2) were investigated for catalyzing the selective catalytic reduction of NO by H2 (H2-SCR). It was found that matched capability of the catalyst activating H2 and that adsorbing NOx under the reaction conditions is much important for the H2-SCR catalyst. For 0.5 wt.%Pt/ZrO2, its relatively larger NOx adsorption capacity and lower capability of activating H2 made its catalytic activity much lower. Some Lewis acid sites were produced by modifying the ZrO2 with niobium oxide, which in turn properly decreased the NOx adsorption capacity and increased the capability of the resulted Pt/Nb1Zr1 catalyst for activating H2. The Pt/Nb1Zr1 catalyst exhibited much higher H2-SCR activity and N2 selectivity compared to Pt/ZrO2.