Title : Harmful gases reduction characteristics according to the additive catalysts and Support types of H2-SCR
Internal combustion engines still account for a large proportion of automobiles. The internal combustion engine still accounts for a significant portion of automobiles and is a major contributor to air pollution and global warming. As a result, air quality regulations are becoming stricter. Regulations on automobiles, construction machinery, ships, and household boilers have been tightened, and air quality is being managed by expanding the air management area nationwide in a manner suitable for local conditions. With the advent of the hydrogen economy in the future, technologies that generate and utilize hydrogen, the cleanest energy source, are in the spotlight with meaningful research ongoing. To date, selective catalytic reduction(SCR) catalysts have been commercialized as a powerful NOx reduction after-treatment technology. In addition, H2-engines have been developed and commercialized, and the concern of NOx and H2 emissions has also been raised. In the research trend of the H2-SCR catalyst, research on reducing NOx using H2 as a reducing agent has been conducted. Previous studies have been conducted on the main catalyst (Pt, Pd, Ag), additive catalysts(Na, La, Ce, Ni, W, Cr, Mn, Mo, etc), support (Al2O3, TiO2, Zeolite, etc), reaction mechanism, etc., mainly to improve the performance of the H2-SCR catalyst. Among various studies using noble metal-based catalysts, platinum has been demonstrated as a suitably active metal showing superior activity for H2-SCR at low temperatures. The purpose of this study is to simultaneously reduce NOx and CO harmful gases according to the promoters and support types of the H2-SCR. The 0.5Pt-2CeO2-5Ru/TiO2 catalyst loaded with 7wt% Ru showed a lower NOx conversion rate compared to than the 0.5Pt-2CeO2/TiO2(STD), but the window shifted to the right, and it showed NOx reduction performance of up to 30% at 175°C. When Zr was loaded, de-NOx performance was not improved at the temperature of 200°C starting from a low catalyst temperature of 75°C. With In the influence of the support types, the 0.5Pt-2CeO2/TiO2 H2-SCR catalyst showed the highest NOx conversion rate below 125°C, and the low-temperature activity of NOx was higher than that of the three zeolite-loaded H2-SCR catalysts. Low temperature activity was improved because the TiO2 has excellent reducing and oxidizing ability. Among the three zeolites, the CO reduction performance of the 0.5Pt-2CeO2/Zeolite(1) catalyst with high Al content was the lowest.
Audience Takeaway Notes:
- In this study, the follwing results were obtained through the harmful gaese reduction characteristisc accoding to the additive catalysts(Ru, Zr) and the support types(TiO2, Zeolites) of H2-SCR
- The 0.5Pt-2CeO2-5Ru/TiO2 catalyst loaded with 7wt% Ru showed a lower NOx conversion rate compared to than the 0.5Pt-2CeO2/TiO2(STD) catalyst, but the window shifted the right, and it showed. NOx reduction performance of up to 30% at 175?. The window moved to the right because a lot of cataly activation energy was required.
- When the additive catalyst Zr was added to the H2-SCR catalyst, it did not affect the catalytic activity, but it did affect the durability or good acid point control.
- The 0.5Pt-2CeO2/TiO2 H2-SCR catalyst showed the highest NOx conversion rate below 125?, and the low-temperature activity of H2-SCR catalyts. The support TiO2 has excellent oxidizing power for chemical substance decomposition such as spillover.
- In the zeolite(Si/Al)-based H2-SCR, the perfomance of the catalyt tended to reduce as the content of Al, Which is less active than Si, increased.