Abstract:The CuCe/ZSM-5 catalysts with different cerium loadings (0, 0.5, 1.0, 1.5 and 2.0 wt.%) was investigated to evaluate the correlation between structural characteristics and catalytic performance for the selective catalytic reduction (SCR) of NO by NH3. It was found that the addition of cerium increased copper dispersion and prevented its crystallization. According to the results of X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H2-TPR), copper species were enriched on the ZSM-5 grain surfaces and part of copper ions was incorporated into the cerium lattice. Addition of cerium improved the redox properties of the CuCe/ZSM-5 catalysts, owing to the higher valence of copper and mobility of lattice oxygen than those of Cu/ZSM-5 catalyst. Hence the introduction of * Corresponding author. Tel.: +86-22-60601278; Fax.: +86-22-60600320 E-mail address: haoqinglan@tust.edu.cn ** Corresponding author. Tel.: +822 2220 0441; fax: +822 2220 2299 (K. Hui)E -mail address: kshui@hanyang.ac.kr (K. Hui) 2 cerium in Cu/ZSM-5 improved significantly NO conversion. On the one hand, the cerium introduction into Cu-Z enhances their low-temperature activities. 95% NO conversion is reached around 197 ºC for Cu-Z while the corresponding temperature value decreases to 148 ºC for CuCe4-Z. On the other hand, the temperature range of efficient NO reduction (95%) also extends to higher temperature when the cerium are added to Cu/ZSM-5. Among the Cu-Ce/ZSM-5 catalysts tested, the CuCe4-Z sample exhibits the highest catalytic activity with the temperature range for 90% NO removal of 148-427 ºC.
The small private online course (SPOC) of Principles of Chemical Engineering for the majors of Chemistry, Material, Environment, Pharmaceutical Sciences, etc., has been constructed by the teaching team of chemical engineering in Zhejiang Normal University. We recorded 101 micro‐videos of knowledge points, which explained in detail the fluid flow, fluid transportation machinery, heat transfer as well as distillation and absorption; and briefly interpreted the operations involving particulate solids, mass transfer equipments, evaporation, extraction, and drying of solids. The SPOC course has been online and run for 2 years on Zhejiang Institutions of Higher Learning Online Open Course Sharing Platform. Our teaching practices show that the online/offline blended learning combines the students’ online self‐study through micro‐videos before class with traditional classroom, and greatly improves the learning efficiency. Meanwhile, the blended learning based on the online courses shares the high‐quality courses and will be the future trend in higher education.
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