Keilholz Simon, Paul Roman, Dorsch Leonhard Yuuta, Kohlmann Holger
Institute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany.
MOLYMET Germany GmbH, Niels-Bohr-Str. 5, 06749, Bitterfeld-Wolfen, Germany.
Chemistry. 2023 Mar 22;29(17):e202203932. doi: 10.1002/chem.202203932. Epub 2023 Feb 17.
The reduction of metal oxides with hydrogen is widely used for the production of fine chemicals and metals both on the laboratory and industry scale. In situ methods can help to elucidate reaction pathways and to gain control over such synthesis reactions. In this study, the reduction of WO and V O with hydrogen was investigated by in situ X-ray powder diffraction with regard to intermediates and the influence of heating rates and hydrogen flow rates. Mixtures of V O , V O and VO in two modifications were identified as intermediates on the way to phase-pure V O . None of the intermediates occurs in a single phase and therefore cannot be prepared this way. In contrast, the intermediates of the WO reduction, H WO and W O , appear consecutively and can be isolated. For both reactions, the heating and flow rates have little influence on the formation of intermediates.
用氢气还原金属氧化物在实验室和工业规模上广泛用于精细化学品和金属的生产。原位方法有助于阐明反应途径并控制此类合成反应。在本研究中，通过原位X射线粉末衍射研究了用氢气还原WO和V₂O₅，涉及中间体以及加热速率和氢气流速的影响。在生成纯相V₂O₃的过程中，V₂O₅、V₂O₄和两种变体的VO混合物被确定为中间体。没有一种中间体以单相形式出现，因此无法通过这种方式制备。相比之下，WO₃还原的中间体H₂WO₄和W₂O₅相继出现并且可以分离出来。对于这两个反应，加热速率和流速对中间体的形成影响很小。
