Nitrogen Adsorption and Surface Texture of High-Area Manganese Oxides Derived from Potassium-Contaminated NHMnO
| Autor: | A.K.H. Nohman, M.I. Zaki |
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| Jazyk: | angličtina |
| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Adsorption Science & Technology, Vol 11 (1994) |
| Druh dokumentu: | article |
| ISSN: | 0263-6174 2048-4038 02636174 |
| DOI: | 10.1177/026361749401100101 |
| Popis: | Nitrogen sorption isotherms have been determined at 77 K on pre-characterised MnO x bulk samples obtained by calcination at 423–873 K of K + -contaminated NH 4 MnO 4 . The isotherms have been analysed for estimating the surface area and pore structure of the test samples adopting the α s -method and standard adsorption data determined on a local reference material (calcination product of the permanganate at 1273 K for 20 h). The most prominent result of the present investigation is that the presence of K + leads to the formation of a channel-structured KMn 8 O 16 bulk phase at 573 K and the following consequent textural modifications: (i) a considerable increase in the surface area to 205 m 2 /g, (ii) the construction of a uniform pore system consisting of slit-shaped pores with narrow entrances, and (iii) the evolution of energetically uniform internal surfaces of considerable area (= 92 m 2 /g). The results also reveal that the test surfaces generally exhibit a low heat towards N 2 adsorption. |
| Databáze: | Directory of Open Access Journals |
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