摘要
用共沉淀法和浸渍法制备了以Mo为主并含有少量金属Ti,Zr,Co ,Ce或La的双组分氮化物 ,利用XRD ,BET和DTA表征了样品的物相组成、孔结构和氮化过程 .结果表明 ,在共沉淀法制备的样品上 ,Co或Zr可以和Mo生成某种无定形复合氮化物CoMoNx 或ZrMoNx;Ti和Mo生成TiN Mo2 N混合物 ;稀土元素Ce或La的钼酸盐不能被氮化 .对于用共沉淀法制备的样品 ,第二组分的加入有利于Mo的氮化 .浸渍法制备的样品上除Mo2 N外 ,还有MoO2 相存在 .不同的制备方法对氮化物的比表面积也有影响 .
Bimetallic nitrides containing Mo with a definite amount of Co, Ti, Zr, Ce or La as an ingredient have been synthesized by nitriding bimetallic oxide precursors with NH 3 via temperature programmed reaction. The oxide precursors were prepared by two methods: coprecipitation of ammonium heptamolybdate with nitrate or sulfate of the second ingredients, and impregnation of MoO 3 with the salt solution above mentioned. The XRD data show that the crystalline phase of nitrides depends upon the preparation methods. For the nitrides in which the bimetallic oxide precursors prepared by coprecipitation, except γ Mo 2N crystalline phase appeared on all samples, the existence of another crystalline phase relates to the second ingredient. An amorphous complex compound CoMoN x or ZrMoN x was probably formed on the sample containing Co or Zr. TiN crystalline phase appeared on the sample with Ti as the second ingredient. As for the samples containing Ce or La, the Ce(MoO 4) 2 or La 2MoO existed. This means that the Ce or La molybdate can not be nitrided. When the bimetallic oxide precursors were prepared by impregnation, corresponding nitrides consisted of γ Mo 2N and MoO 2 species, and no second ingredient was observed. The surface area of nitrides prepared by coprecipitation is much larger than that prepared by impregnation.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2000年第3期225-228,共4页
关键词
钼催化剂
制备
共沉淀法
浸清法
双金属氮化物
bimetallic nitride, molybdenum catalyst, crystalline structure, catalyst preparation, X ray diffraction, differential thermal analysis
