The NOxemitted from diesel engine would cause serious health and environmental issues, and the selective catalytic reduction of NOxby NH3is one of the most efficient technologies to eliminate the NOxemission. Due to the excellent NOxconversion performance, prominent high-temperature hydrothermal stability, and low cost, the Cu-SAPO-34 catalyst is regarded as the promising catalyst, which could be applied in diesel after-treatment system to meet the China VI standard. However, Cu-SAPO-34 catalyst is sensitive to the low-temperature vapor, which limits its practical application.
Recently, a research group led by Prof. TIANPeng and Prof. LIU Zhongmin from theDalian Institute of Chemical Physics(DICP) of the Chinese Academy of Sciences studied the effect Si environments on the moisture stability of Cu-SAPO-34 catalysis. They regulated the catalytic performance and the moisture stability by controlling the Si environments of SAPO-34 zeolites.
This study was publishedinJournal of Catalysison September 11.
SAPO-34s with varying Si contents templated by bulkytetraethylammonium hydroxide(TEAOH) were prepared. Then the Cu-SAPO-34s with similar Cu loadings, isolated Cu2+contents and Brönsted acid sites were obtained. Both the ratio of Si islands and the acid strength of Cu-SAPO-34s increase as the increment of Si content. The results show that theCu-SAPO-34 with low Si content and abundantSi(4Al)species (sample Si-7.7)perform the highest turnover frequency and the lowest activation energy.Upon hydration treatment, the textural properties, strong acid sites and reducibility of isolated Cu2+ions show a decrease, such deterioration intensifies with the incremental Si islands in the catalysts due to the easier occurrence of Si migration and the formation of larger Si islands. Sample Si-7.7exhibits the best moisture stabilityand thus well-preserved denitration performance. These results imply thatpractical Cu-SAPO-34 catalystwith superior activity and moisture stabilitymay be achieved by controlling the Si environments of SAPO-34 templated by bulky amines.
This research was supported by the National Natural Science Foundation of China, China Postdoctoral Science Foundation and Key Research Program of Frontier Sciences, Chinese Academy of Sciences.(text by CAOYi)
The effect of Si environments on NH3 selective catalytic reduction performance and moisture stability of Cu-SAPO-34 catalysts. Yi Cao, Dong Fan, Dali Zhu, Lijing Sun, Lei Cao, Peng Tian*, Zhongmin Liu*, JOURNAL OF CATALYSIS, 391:404-413, 2020.
