One-step hydrothermal synthesis of Cu-SAPO-34/cordierite and its catalytic performance on NOx removal from diesel vehicles

Cu-SAPO-34/cordierite catalysts were prepared via one-step hydrothermal synthesis method and their performances to remove NOx from the diesel vehicle exhaust were evaluated. The morphology, structure, Cu content and valence state were characterized by SEM, XRD, ICP and XPS, respectively. The experimental results show the active component Cu of the catalysts via in situ synthesis could significantly improve the selective catalytic reduction (SCR) activities of NOx and the optimal Cu content is in the range of 0.30%-0.40% (mass fraction). No N2O is detected by gas chromatograph (GC) during the evaluation process, which implies that NOx is almost entirely converted to N2 over Cu-SAPO-34/cordierite catalyst. The conversion rate of NOx to N2 by NH3 over catalyst could almost be up to 100% in the temperature range of 300-670 °C with a space velocity of 12000 h−1 and it is still more than 60% at 300-620 °C under 36000 h−1. The catalysts also show the good hydrothermal and chemical stability at the atmosphere with H2O.