Publication details
NOVEL CeWTiOx CATALYST FOR LOW TEMPERATURE SELECTIVE CATALYTIC REDUCTION
| Authors | |
|---|---|
| Year of publication | 2022 |
| Type | Appeared in Conference without Proceedings |
| MU Faculty or unit | |
| Citation | |
| Description | NOx is a major part of acidic rains and contributes also to formation of tropospheric ozone. For this reason, NOx emissions from both stationary and mobile sources are currently under great supervision not only in the EU, and the USA but also in countries that have historically adopted older European or American emission standards and limits.1 The most common method for NOx removal is a selective catalytic reduction (SCR), which uses ammonia as a reducing agent (NH3-SCR).2 The most frequently used catalysts for NH3-SCR are mixed-metal oxides based on V2O5 or Fe, Cu exchanged zeolites. 3 Cu, Fe exchanged zeolites are generally used for applications where high-temperature conversion and stability (above 500 °C) is required. However, the conversion at low temperatures of these materials is insufficient and the highest emissions of current both low-duty and heavy-duty vehicles, and machinery are during cold starts, i.e., low catalyst temperatures. Mixed-metal oxides catalysts based on vanadium pentoxide have better conversion at low temperatures, but the conversion at higher temperatures decreases significantly and poses poor thermal stability. A promising alternative are mixed-metal oxides based on CeO2, WO3 and TiO2. 4 Between 220-450 °C, this material shows NOx conversion higher than 90 %, and remained high conversion even under high GHSV. Unlike commercial de-NOx mixed-metal oxide catalysts, this material does not contain vanadium, which is toxic and can be released into the environment. In this work the CeWTiOx mixed-metal oxide catalyst was synthesized by several chemical routes (hydrothermal synthesis, electrospinning and nonhydrolytic sol-gel5 ) with a constant stoichiometric ratio of 2:1:10, forming Ce0.2W0.1TiOx. Different synthetic routes gave rise to different morphologies of the material such as nanofibers, xerogel, and bulk which affect its key properties such as thermal stability, specific surface area, porosity, and strength of the material. These factors were compared among different synthetic routes and morphologies in order to find the best approach for this application |