Synthesis and Evaluation of Ceramic‐Anchored Cu‐Ce‐MnO _x Catalyst for Low Temperature Reduction of Diesel Engine NO _x Emissions Using Liquefied Petroleum Gas or Adblue as Reductants

Abstract

ABSTRACT Manganese oxide‐based catalyst doped with copper and cerium was synthesized through microwave irradiation and successfully anchored on a ceramic support. Fourier Transform Infrared Radiation study showed Mn‐O bond at 529 cm −1 while X‐ray Fluorescence confirmed the availability of Cu, Ce and Mn in the ceramic matrix. Examination by SEM revealed active sites in addition to the catalyst aggregate particle size diameter as 707 mm. Energy Dispersive X‐ray established the presence of copper, cerium and manganese after catalyst synthesis. Catalytic effect of Cu‐Ce‐MnO x was studied using liquefied petroleum gas as the hydrocarbon reductant and performance comparison was made with NH 3 , a commonly used reductant from AdBlue solution. Sulfur dioxide poisoning resistance, hydrothermal stability and low temperature activity (< 50°C) were the critical parameters investigated by having Cu‐Ce‐MnO x catalyst placed after the water‐cooling unit. The parameters were optimized by testing Cu‐Ce‐MnO x catalyst at 3, 6, and 9 kg engine loads to reflect the expected real driving NO x emission reduction potential of the catalyst. NO x reduction efficiency was 26% at 28°C for LPG‐Cu‐Ce‐MnO x and 60% at 29°C for NH 3 ‐Cu‐Ce‐MnO x . White biuret deposits were observed around the injection point due to low temperature decomposition of AdBlue solution. Biuret would lower the catalytic activity by clogging hence reduced number of catalyst active sites. This work successfully shows that this ceramic anchored Cu‐Ce‐MnO x catalyst has a potential application at almost room temperature NO x reduction. The anchored catalyst has the potential for integration in Diesel automobile exhaust, though it has a lower NO x conversion efficiency with LPG, compared to the conventional AdBlue.