论文部分内容阅读
采用XRD、Raman、XPS及催化剂性能评价等手段,考察了Bi_3(FeO_4)(MoO_4)_2和Fe_2(MoO_4)_3分别存在及两者共存时对Bi-Mo复氧化物体系催化性能的影响.结果表明,这两种含Fe物种的存在都有助于改善Bi-Mo系复氧化物催化剂对丙烯选择氧化反应的催化性能.但两者在作用机理上有所不同.Fe_2(MoO_4)_3本身无催化活性,但在反应条件下可部分还原为FeMoO_4形成Fe~(3+)/Fe~(2+)氧化还原对;且其地结构上与α-Bi_2(MoO_4)_3相匹配,这些因素都有助于促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生,从而提高催化性能.Bi_3(FeO_4)(MoO_4)_2在反应条件下也可形成Fe~(3+)/Fe~(2+)氧化还原对,但由于其Fe~(3-)所处的化学环境与Fe_2(MoO_4)_3很不相同,且Fe的含量也不及Fe_2(MoO_4)_3,因此它在促进催化体系中电子和氧物种的传递及催化剂表面活性中心的再生等方面的性能较差,但它对提高催化剂表面的活性中心(Bi-Mo对)数目有贡献.
The effects of Bi_3 (FeO_4) _2 and Fe_2 (MoO_4) _3 respectively on the catalytic performance of Bi-Mo complex oxide system were investigated by means of XRD, Raman, XPS and catalyst performance evaluation. It is indicated that the existence of these two Fe-containing species can help to improve the catalytic performance of the Bi-Mo-based multi-oxide catalyst for the selective oxidation of propylene, but the mechanism of action is different for both Fe 2 (MoO 4) 3 itself But can be partially reduced to FeMoO_4 to form Fe ~ (3 +) / Fe ~ (2+) redox couple under the reaction conditions; and its structure is matched with α-Bi_2 (MoO_4) _3 Which can help to promote the transfer of electron and oxygen species in the catalytic system and the regeneration of the catalyst surface active center, thereby improving the catalytic performance.Bi_3 (FeO_4) (MoO_4) _2 can also form Fe3 + / Fe ~ However, due to its very different chemical environment from Fe 2 (MoO 4) 3 and its Fe content less than that of Fe 2 (MoO 4) 3, The poor performance of intermediate electron and oxygen species transport and regeneration of the catalyst surface active sites, however, The number of centers (Bi-Mo on) contribute.