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论文类型：期刊论文

发表时间：2008-09-22

发表刊物：JOURNAL OF ALLOYS AND COMPOUNDS

收录刊物：SCIE、EI、Scopus

卷号：464

期号：1-2

页面范围：488-496

ISSN号：0925-8388

关键字：nitride materials; catalysis; crystal structure; vacancy information; X-ray diffraction

摘要：A series of bulk and alumina-supported nitrides of metals (V, Mo, Fe and Cc) were synthesized by NH3-temperature-programmed reaction and characterized by X-ray diffraction (XRD) and temperature-programmed desorption techniques. The formation of bulk Co4N and Co4N/gamma-Al2O3 was further confirmed using X-ray photoelectron spectroscopic analysis. The catalytic activities of these metal nitrides for NO decomposition were evaluated. Their activities for NO decomposition ranked in the order of Co4N > Fe3N > Mo2N > VN and Co4N/gamma-Al2O3 > Fe3N/gamma-Al2O3 > Mo2N/gamma-Al2O3 > VN/gamma-Al2O3. The relationship between crystal structures and catalytic activities was investigated. The results indicated that metal nitrides with higher vacancy concentration exhibited higher activities for NO decomposition. There was a stronger interaction between the metal nitride phases and gamma-Al2O3 support. It was suggested that Co4N/gamma-Al2O3 exhibited thermal stability significantly higher than that of bulk counterpart, owing to the strong interaction between the Co4N phase and gamma-Al2O3 support. We applied the XRD technique to examine the structural changes of Co4N/gamma-Al2O3 catalysts during the reactions. The results indicated that the rapidly loss in catalytic activity was due to the bulk oxidation of Co4N/gamma-Al2O3. In the NO-H-2 reaction, the oxygen generated during NO dissociation was partly reduced by H-2 and partly incorporated into the nitride lattice. By the addition of H-2 in feed gas at 600 degrees C, one can retain the active Co4N/gamma-Al2O3 phase by minimizing the presence of surface oxygen. (C) 2007 Elsevier B.V. All rights reserved.