摘要
采用三种共沉淀工艺制备了甲烷部分氧化制甲醇用ＭｏＣｒＶＢｉＳｉ多元复合氧化物催化剂，发现不同共沉淀工艺过程对催化剂体相中Ｍｏ，Ｃｒ，Ｖ，Ｂｉ的含量及催化剂的活性有一定影响．ＸＲＤ结果表明，与Ｃｒ相比，Ｂｉ与Ｖ及Ｍｏ之间有更强的结合能力．非催化与催化条件下的动力学评价结果表明，甲烷的深度氧化产物ＣＯ主要是通过甲醛生成的，而ＭｏＣｒＶＢｉＳｉ多元复合氧化物催化剂对控制甲醛的氧化起到非常重要的作用．制备过程中加入适量的草酸，对提高催化剂活性有利．在甲烷转化率为１０％时，醇醛总选择性可达８０％．
Mo Cr V Bi Si multicomponent oxide catalysts were prepared by different coprecipitation methods. These catalysts were characterized by XRF and XRD. It was shown that the Mo content in the catalysts and their performance were strongly influenced by different coprecipitation methods. Bi could combine with V(Ⅴ) and Mo(Ⅵ) to form BiVO 4 and γ Bi 2MoO 6, respectively, whereas Cr seemed rarely to react with MoO 2- 4. Only single Cr 2O 3 crystalline phase could be formed in the presence of Bi. The catalysts were tested in the selective oxidation of CH 4 with O 2. Homogeneous gas phase oxidation of CH 4 was also investigated for comparison. As a result, the deep oxidation of CH 4 was found to follow a main reaction path, where CO was formed from HCHO. Over certain catalysts, the CH 3OH HCHO selectivity in excess of 80% could be obtained at CH 4 conversion of 10%. It was believed that a new pathway to CH 3OH and HCHO might be opened over the catalysts, meanwhile the pathway leading to CH 4 deep oxidation in gas phase was inhibited.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
1998年第5期406-410,共5页
基金
国家自然科学基金
关键词
甲烷
部分氧化
催化剂
甲醇合成
Methane, Methanol, Partial oxidation, Coprecipitation, Metal oxide catalyst
