Dey Archan, Lenders Jos J M, Sommerdijk Nico A J M
Laboratory of Materials and Interface Chemistry and Soft Matter CryoTEM Research Unit, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Faraday Discuss. 2015;179:215-25. doi: 10.1039/c4fd00227j. Epub 2015 Apr 13.
We show that by reacting ferrihydrite (FeH) with Fe((II)) ions and subsequently increasing the pH, magnetite is formed through a multi-step nucleation process mediated by monodisperse FeH-Fe((II)) primary particles. The interaction of these primary particles with a transient green rust phase leads to the formation of smaller secondary particles which form the feedstock for magnetite formation. Surprisingly, the presence of a polypeptide additive prevents the formation of green rust as an Fe((II))-rich intermediate phase, and leads to the formation of amorphous aggregates of FeH-Fe((II)) particles which subsequently transform into the final magnetite nanocrystals. The observation of multiple transitions and the involvement of disordered precursor phases in this bioinspired crystallization route is important for our understanding of the nucleation of magnetite in geological and biological environments, and may lead to new approaches in the sustainable synthesis of this technologically important mineral.
我们表明，通过使水铁矿（FeH）与Fe（II）离子反应，随后提高pH值，磁铁矿通过由单分散FeH-Fe（II）初级颗粒介导的多步成核过程形成。这些初级颗粒与瞬态绿锈相的相互作用导致形成较小的次级颗粒，这些次级颗粒构成了磁铁矿形成的原料。令人惊讶的是，多肽添加剂的存在阻止了作为富Fe（II）中间相的绿锈的形成，并导致形成FeH-Fe（II）颗粒的无定形聚集体，这些聚集体随后转变为最终的磁铁矿纳米晶体。在这条受生物启发的结晶途径中观察到的多个转变以及无序前驱体相的参与，对于我们理解地质和生物环境中磁铁矿的成核非常重要，并且可能会导致在可持续合成这种具有重要技术意义的矿物方面产生新的方法。
