Insight into the H2S selective catalytic oxidation performance on well-mixed Ce-containing rare earth catalysts derived from MgAlCe layered double hydroxides
| Autor: | Fenglian Zhang, Siqiu Qu, Hongling Yang, Xin Zhang, Zhengping Hao, Guoxia Jiang |
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| Rok vydání: | 2018 |
| Předmět: |
inorganic chemicals
Environmental Engineering Health Toxicology and Mutagenesis Catalyst support Inorganic chemistry chemistry.chemical_element 02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences Catalyst poisoning Catalysis Environmental Chemistry heterocyclic compounds Lewis acids and bases Waste Management and Disposal organic chemicals Layered double hydroxides 021001 nanoscience & nanotechnology Pollution Sulfur 0104 chemical sciences chemistry Chemisorption engineering 0210 nano-technology Selectivity |
| Zdroj: | Journal of Hazardous Materials. 342:749-757 |
| ISSN: | 0304-3894 |
| Popis: | A series of well-mixed Ce-containing MgAlCe rare earth catalysts derived from layered double hydroxides were synthesized and tested for H2S selective catalytic oxidation. Particularly, no chemisorption O-vacancies but intrinsic defect sites were present on catalyst surface. Significantly, the catalysts exhibited excellent catalytic activity, reasonable durability, and outstanding sulfur selectivity (100%) at relatively low temperatures. Furthermore, the catalyst followed a step-wise mechanism, and the catalyst deactivation was due mainly to the slower oxidation rate of Ce3+ to Ce4+ by O2 as compared to the reduction rate of Ce4+ to Ce3+ by H2S. Particularly, the added water, a Lewis base, can compete with inefficient S8 catalyst for the occupation of Lewis acid sites and active sites. Meanwhile, it can change the characteristics of catalyst surface, resulting in sulfur existing form transforming from inefficient S8 catalyst to inactive S3. Thus, lead to a decrease of deposited inefficient S8 catalyst content. Consequently, decrease the catalytic activity. |
| Databáze: | OpenAIRE |
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