Enhancing catalytic converter performance: effects of noble metals and rare earth washcoating on CO and NOx conversion

Abstract

Catalytic converters are used to convert harmful gases such as carbon monoxide (CO), nitrogen oxides (NOₓ), and unburned hydrocarbons (HC) into less harmful or harmless gas emissions like carbon dioxide (CO₂), nitrogen (N₂), and water vapor (H₂O). In this study, supported catalysts for use of these CO and NO were developed by deposition of noble metals on cordierite (Cor) support with impregnation (IMP) in aqueous media. Effects of catalysts and washcoating for cordierite support were evaluated for carbon monoxide and nitrogen oxide activity in a batch reactor. They were characterized using XRD, BET, Raman, FTIR, and SEM–EDS. All catalysts were found to be effective in carbon monoxide conversion. The washcoating of catalyst support with cerium, lanthanum, zirconium, and yttrium changed the activity of the catalyst. The catalytic activity increased 20% with the washcoating. The coating enhanced catalytic activity by using cerium and zirconium oxides which improved thermal stability, while rare earth elements like lanthanum and yttrium helped stabilize the catalyst and optimize carbon monoxide conversion although some combinations had a negative impact on performance. It was observed that the C-Cor-Rh catalyst (99.96%) and C-Cor-Pd converted almost all (99.94%) harmful NO gas. The results showed that these catalysts had high efficiency for converting harmful NO_x gaseous to different components. This study shown that innovative, cost-effective and highly efficient catalytic converters can be obtained by shaping the quality and quantity of the precious metals to be dopped to the support material through effective washcoating modeling.